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Everything you need to know about Computed Tomography (CT) & CT Scanning

April 2019 Imaging Pearls - Educational Tools | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ April 2019

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Adrenal

  • “Primary adrenal lymphoma without lymphadenopathy or other extra-nodal disease is rare .Secondary adrenal involvement is seen in about 4% of diffuse non- Hodgkin’s lymphoma (NHL), and 43% of these cases are bilateral. About two-thirds of patients with bilateral adrenal involvement had adrenal insufficiency.”
    Bilateral adrenal abnormalities: imaging review of different entities
    Meshal Ali Alshahrani et al.
    Abdom Radiol (2019) 44:154–179
  • ”Adrenal lymphoma tend to grow in an infiltrative manner, maintaining the adreniform appearance. However, it may progress and have heterogeneous enhancement with necrotic or cystic components, which would pose a diagnostic challenge. On CT, an adrenal lymphomatous mass can be homogeneous with washout features similar to other malignancies. Prior to treatment, calcification is rare.”
    Bilateral adrenal abnormalities: imaging review of different entities
    Meshal Ali Alshahrani et al.
    Abdom Radiol (2019) 44:154–179
  • ”In unwell patients with hypoperfusion status, the adrenal glands demonstrate symmetric bilateral intense enhancement with attenuation values matching the great vessels such as abdominal aorta or inferior vena cava (IVC). IVC slit-like flattening, increased renal enhancement and diffuse bowel wall thickening are another supportive diagnostic imaging clues of hypoperfusion complex. This phenomenon is related to a sympathetic response to shock to preserve the perfusion of vital organs including the adrenals.”
    Bilateral adrenal abnormalities: imaging review of different entities
    Meshal Ali Alshahrani et al.
    Abdom Radiol (2019) 44:154–179
  • Bilateral Adrenal Masses: Benign
    - Adenoma
    - Myelolipoma
    - Infection (TB)
    - Hematoma
  • Bilateral Adrenal Masses: Non-Mass Like
    - Adrenal hyperplasia
    - Adrenal atrophy
    - Adrenal calcifications (Wolman’s Disease)
    - Intense enhancement (hypoperfusion syndrome)
  • “A laparoscopic approach to adrenal tumor excision is the preferred surgical method, due to associated shorter recovery time and lower risk of operative complications, relative to the open approach. Laparoscopic adrenalectomy involves the transabdominal insertion of a small video chip camera, and other surgical instruments, into the peritoneal space through specially designed ports, allowing the surgeon to resect an adrenal tumor through 5–12 mm incisions. Relative to an open approach, this technique provides lower perioperative morbidity and mortality, shorter hospitalization time, better cosmetic results, reduced postoperative narcotic analgesic requirements, and improvement in the post- operative interval to normal dietary intake.”
    What the radiologist needs to know: the role of preoperative computed tomography in selection of operative approach for adrenalectomy and review of operative techniques
    Steven P. Rowe,Carolina Lugo-Fagundo, Hannah Ahn, Elliot K. Fishman, and Jason D. Prescott
    Abdom Radiol (2019) 44:140–153
  • However, controversy persists as to the appropriateness of the laparoscopic approach under some circumstances, particularly for large adrenal tumors and for suspected ACC. For ACC in particular, open adrenalectomy has been associated with improved oncologic outcomes, secondary to lower rates of intraoperative tumor capsule violation and to lower risk of tumor margin positivity, despite the more significant short-term morbidity inherent to this invasive technique (relative to its laparoscopic counterpart).
    What the radiologist needs to know: the role of preoperative computed tomography in selection of operative approach for adrenalectomy and review of operative techniques
    Steven P. Rowe, Carolina Lugo-Fagundo, Hannah Ahn, Elliot K. Fishman, and Jason D. Prescott
    Abdom Radiol (2019) 44:140–153
  • “Adrenal CT scanning provides information that determines the potential for successful laparoscopic adrenal resection, including lesion size, characteristics of surrounding anatomy, and tumor features suggestive of malignancy (including degree of tissue heterogeneity, lesion vascularity, presence of calcifications, necrosis, and local invasion).”
    What the radiologist needs to know: the role of preoperative computed tomography in selection of operative approach for adrenalectomy and review of operative techniques
    Steven P. Rowe, Carolina Lugo-Fagundo, Hannah Ahn, Elliot K. Fishman, and Jason D. Prescott
    Abdom Radiol (2019) 44:140–153
  • “Scenarios in which image-guided biopsy may provide useful information are limited to cases of suspected metastasis to an adrenal gland, for which biopsy material can facilitate identification of the originating site for an otherwise unknown primary tumor, and to cases of adrenal infection, for which the causative organism is unknown.”
    What the radiologist needs to know: the role of preoperative computed tomography in selection of operative approach for adrenalectomy and review of operative techniques
    Steven P. Rowe, Carolina Lugo-Fagundo, Hannah Ahn, Elliot K. Fishman, and Jason D. Prescott
    Abdom Radiol (2019) 44:140–153
  • “Feo and colleagues reported that experienced surgeons could resect adrenal tumors 5 cm laparoscopically, with surgical outcomes similar to those associated with smaller tumors, although tumors >8 cm were associated with longer operative times.”
    What the radiologist needs to know: the role of preoperative computed tomography in selection of operative approach for adrenalectomy and review of operative techniques
    Steven P. Rowe, Carolina Lugo-Fagundo, Hannah Ahn, Elliot K. Fishman, and Jason D. Prescott
    Abdom Radiol (2019) 44:140–153
  • “Given a generally accepted increase tumor recurrence risk associated with laparoscopic ACC resection, open adrenalectomy, during which direct tumor palpation is used to assess disease extent and preserve the tumor capsule, is the preferred approach for ACC. In light of this preference, preoperative identification of adrenal malignancy becomes critically important to the surgeon.”
    What the radiologist needs to know: the role of preoperative computed tomography in selection of operative approach for adrenalectomy and review of operative techniques
    Steven P. Rowe, Carolina Lugo-Fagundo, Hannah Ahn, Elliot K. Fishman, and Jason D. Prescott
    Abdom Radiol (2019) 44:140–153
  • Under such circumstances, laparoscopic adrenalectomy may be considered, as metastatic disease to the adrenal gland, unlike ACC, has not generally been associated with increased risk of peritoneal carcinomatosis. Nonetheless, tumor imaging features in these cases, including metastasis size and evidence for associated local invasion, drive selection of operative approach, just as in cases of ACC.”
    What the radiologist needs to know: the role of preoperative computed tomography in selection of operative approach for adrenalectomy and review of operative techniques
    Steven P. Rowe, Carolina Lugo-Fagundo, Hannah Ahn, Elliot K. Fishman, and Jason D. Prescott
    Abdom Radiol (2019) 44:140–153
  • Adrenalectomy is the standard of care when treatment is indicated for an adrenal tumor. Though dissertation of the various modalities available for adrenal imaging is beyond the scope of this manuscript, assessment of imaging characteristics that inform selection of adrenalectomy operative approach is effectively achieved by multi-phase CT scanning (including tumor size, probability of malignant character, identification of local tumor invasion and assessment for local/distant metastatic disease).
    What the radiologist needs to know: the role of preoperative computed tomography in selection of operative approach for adrenalectomy and review of operative techniques
    Steven P. Rowe, Carolina Lugo-Fagundo, Hannah Ahn, Elliot K. Fishman, and Jason D. Prescott
    Abdom Radiol (2019) 44:140–153
  • Laparoscopic left adrenalectomy
  • Laparoscopic right adrenalectomy
  • Bilateral Adrenal Masses: Malignant
    - Metastases (renal cell carcinoma, melanoma, hepatoma)
    - Lymphoma
    - Neuroblastoma
    - Pheochromocytoma
  • “Texture analysis has a potential role in distinguishing benign from malignant adrenal nodules on CECT and may decrease the need for additional imaging studies in the workup of incidentally discovered adrenal nodules.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Current imaging methods can diagnose lipid-rich adenomas with the use of either unenhanced CT or chemical-shift MRI and can diagnose lipid-poor adenomas on the basis of calculation of the percentage washout on contrast-enhanced CT (CECT).”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Image-based texture analysis is a quantitative technique that provides a measure of lesion heterogeneity on the basis of local variations in image brightness. First-order statistics- based texture analysis evaluates the number of pixels that have a particular gray-level value within a defined ROI. First-order texture analysis does not account for the location of the pixels within the ROI. Second-order statistics- based texture analysis evaluates the location and spatial interrelationship s between pixels of variable gray-level values.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • For example, first-order texture analysis can determine how many pixels have attenuation of 0 HU within an adrenal nodule. Second-order texture analysis can determine whether those pixels with an attenuation of 0 HU within an adrenal nodule are distributed evenly or are clustered in groups.
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Texture analysis of CECT images showed higher diagnostic performance for the diagnosis of malignancy, compared with CECT attenuation. The performance of select individual CECT texture features (long-run high gray-level emphasis, entropy, and short-run low gray-level emphasis) were comparable to unenhanced attenuation on CT and the SII on MRI, which are the standard diagnostic imaging tests used to distinguish adrenal adenomas from metastases in clinical practice.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • Increased tumor heterogeneity is the most likely reason for the ability of texture analysis to predict adrenal malignancy on CECT. As is seen in Figure 2, lipid-poor adenomas appeared homogeneous on CECT, compared with malignant lesions, which appeared heterogeneous. We speculate that the administration of contrast material may make lipid- poor adenomas appear more homogeneous because both lipid-rich and lipid-poor areas will have uptake of contrast medium.
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Malignant adrenal lesions become more heterogeneous after contrast material administration because of tumor angiogenesis and increased conspicuity of tumor necrosis. In support of our theory, a recent study by Sasaguri et al. showed that adrenal metastases from renal carcinoma showed visibly higher internal heterogeneity, compared with benign adrenal masses on CECT.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • Another limitation of the present study is the retrospective nature of the data acquisition. Because this is an observational study, the type of scanner used for each patient was not controlled. One cannot underestimate the potential impact of variation in CT and MR image quality on the results of texture analysis. This factor alone represents a major challenge when one considers the robustness of applying texture analysis in the clinical setting.
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “In summary, the results of the present study indicate that the use of texture analysis for evaluation of adrenal nodules works best with CECT. This finding suggests that CT texture analysis may have a potential role in distinguishing benign lipid-poor ad- enomas from adrenal malignancy on single- phase CECT. Furthermore, the application of texture analysis may potentially decrease the need for additional imaging studies to workup incidentally discovered adrenal nodules.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
Chest

  • OBJECTIVE. Diagnostic imaging has traditionally relied on a limited set of qualitative imaging characteristics for the diagnosis and management of lung cancer. Radiomics—the extraction and analysis of quantitative features from imaging—can identify additional imaging characteristics that cannot be seen by the eye. These features can potentially be used to diagnose cancer, identify mutations, and predict prognosis in an accurate and noninvasive fash- ion. This article provides insights about trends in radiomics of lung cancer and challenges to widespread adoption.
    CONCLUSION. Radiomic studies are currently limited to a small number of cancer types. Its application across various centers are nonstandardized, leading to difficulties in comparing and generalizing results. The tools available to apply radiomics are specialized and limited in scope, blunting widespread use and clinical integration in the general population. Increasing the number of multicenter studies and consortiums and inclusion of radiomics in resident training will bring more attention and clarity to the growing field of radiomics.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • OBJECTIVE. Diagnostic imaging has traditionally relied on a limited set of qualitative imaging characteristics for the diagnosis and management of lung cancer. Radiomics—the extraction and analysis of quantitative features from imaging—can identify additional imaging characteristics that cannot be seen by the eye. These features can potentially be used to diagnose cancer, identify mutations, and predict prognosis in an accurate and noninvasive fashion. This article provides insights about trends in radiomics of lung cancer and challenges to widespread adoption.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • CONCLUSION. Radiomic studies are currently limited to a small number of cancer types. Its application across various centers are nonstandardized, leading to difficulties in comparing and generalizing results. The tools available to apply radiomics are specialized and limited in scope, blunting widespread use and clinical integration in the general population. Increasing the number of multicenter studies and consortiums and inclusion of radiomics in resident training will bring more attention and clarity to the growing field of radiomics.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Radiomics is defined as the quantification of the phenotypic features of a lesion from medical imaging (i.e., CT, PET, MRI, ultrasound). These features include lesion shape, volume, texture, attenuation, and many more that are not readily apparent or are too numerous for an individual radiologist to assess visually or qualitatively. In other words, radiomics is the process of creating a set of organized data based on the physical properties of an object of interest.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Regardless of lesion histology and location, the workflow in radiomics remains similar. Images of the lesion, typically CT images, are acquired. The images are segmented to define the outer limits of a given lesion. Specific phenotypic features are then selected, extracted from the images, and recorded. Finally, data analysis is performed on the recorded data. Image features can be extracted and analyzed in either 2D or 3D: 2D refers to segmentation and analysis of radiomic metrics on a single-slice image, whereas 3D refers to the same process across the entire volume of a tumor (many slices).
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Image features can be extracted and analyzed in either 2D or 3D: 2D refers to segmentation and analysis of radiomic metrics on a single-slice image, whereas 3D refers to the same process across the entire volume of a tumor (many slices). Therefore, 3D radiomics, by definition, requires analysis of the entire volume of tumor. In general, feature extraction and analysis are easier and faster in 2D than in 3D, but 3D may theoretically carry more information. Two-dimensional radiomics is used more commonly, but 3D radiomics is appealing with regard to analyzing intratumoral heterogeneity in cases in which different parts of a tumor may exhibit differing histologic subtypes.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “Segmentation of a lesion is the act of extracting or isolating a lesion of interest (e.g., lung nodule) from the surrounding normal lung. Features are then extracted and are further analyzed directly from the segmented lesion. This can be thought of in distinction to deep learning, where an algorithm must learn to automatically extract features from an unsegmented image.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Lesion segmentation can be done either manually or in an automated fashion. Manual segmentation—that is, segmentation performed by a trained observer who manually outlines the lesion of interest—is time-consuming and is more prone to interobserver variability and subjectivity than semiautomated and fully automated segmentation. Manual segmentation is important when accuracy of the tumor outline (i.e., lesion shape and size) is needed.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Shape is one of the feature categories understood as both semantic and agnostic. It is a category of features that includes diameter measurements (e.g., minimum, maximum) and their derivatives including volume, ratio of diameters, surface-to-volume ratio, and compactness. Diameter measurements and their derivatives are among the most commonly assessed features. Semantic descriptions such as round, oval, and spiculated are understood agnostically by a varied lexicon that attempts to determine how irregular the object is. In the shape category, tumor volume has shown the most promise in predicting treatment response.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “Texture in radiomics broadly refers to the variation in the gray-scale intensities of adjacent pixels or voxels in an image. Depending on the technique involved, texture features are categorized into first, second, and higher-order statistical measures. The first-order statistical measures are composed of features that account for variations in gray-scale intensities without accounting for their spatial location or orientation on the image. For example, a histogram of pixel or voxel intensities, which is a visual representation of the distribution of gray-scale intensity values on an image, is the most common technique to derive the first-order texture measures.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Second-order texture metrics encompass hundreds of features derived by evaluating the relationship of adjacent pixels in an ROI or across the entire lesion. These metrics account for both the intensity of a gray-scale value and its location or orientation in the image. CT images are formed from a 3D matrix of data that is used to determine the amount of gray-level color to display for a given image pixel. Texture or heterogeneity refers to analysis of adjacent pixels of gray color to determine the relationship between them; if there are wide variances in the amount of gray color in a given area, then a lesion is considered more heterogeneous or to have a coarse texture.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “Texture has shown the most promise in predicting the presence of malignancy and prognosis. Local binary patterns (LBPs) and gray-level co-occurrence matrices (GLCMs) are most often used in this. However, evaluations of nodule heterogeneity or texture are not limited to LBPs or GLCMs. Numerous alternative methods that attempt to extract patterns from an image via a series of mathematic transformations or filters applied to the image, including Laws’ energy descriptors, fractal analysis, and wavelet analysis, are being increasing applied. This latter group of texture metrics includes higher-order statistical measures. Texture analysis has practical applications; for example, Parmar and colleagues showed that texture features in lung cancer were significantly associated with tumor stage and patient survival.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504

  • “Segmentation and feature recognition currently rely on the initial identification of a nodule by a radiologist. Thus, the near-term and medium-term role of radiomics is likely to be as a support tool in which radiomics is integrated with traditional radiologic and invasive histologic information. We should note that many prior studies achieved highest accuracy when radiomic data were viewed in light of genetic and clinical information.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “Most importantly, the study of radiomics must be drastically expanded to account for the numerous clinical and radiologic presentations of lung cancer. Radiomics is predicated on creating tools to more accurately diagnose lung cancer and determine prognosis of patients with lung cancer in a noninvasive fashion. However, the tools available to practice radiomics are specialized and limited in scope, blunting wide-spread use and clinical integration in the general population. Looking forward, we believe that increasing the number of multicenter studies and consortiums and inclusion of radiomics in resident training will bring more attention to the growing field of radiomics.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “ Other challenges for radiomics include advancing interinstitutional standards for image acquisition and reconstruction parameters and the development of a unified lexicon. Radiomic data are affected by different image acquisition and reconstruction parameters (e.g., contrast timing, slice thickness, reconstruction algorithm, tube voltage, tube current, and so on) that can affect the reproducibility of radiomic features . Many radiomic studies have relied on a heterogeneous dataset of imaging using a mixture of these parameters. Standardized imaging parameters, including consistent contrast dose, timing, and radiation dose levels, will likely need to be implemented for radiomic studies.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Furthermore, radiomics can be performed in 2D or 3D. Two-dimensional radiomics is applied to a single image slice, and the resulting radiomic features can vary from slice to slice. Three-dimensional radiomics is applied to the entire volume of a tumor. The potential differences between these two fundamentally different approaches require further evaluation. In addition, radiomics is a multidisciplinary field with experts from different backgrounds who approach radiomics in different ways. These experts often collaborate and have to understand and incorporate the methods and rationale of sometimes unfamiliar disciplines. For example, computer science researchers may have limited knowledge and experience with medical image acquisition and reconstruction. A unified lexicon will be necessary to maintain consistency, especially for researchers who have limited experience with medical imaging.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
Deep Learning

  • OBJECTIVE. Diagnostic imaging has traditionally relied on a limited set of qualitative imaging characteristics for the diagnosis and management of lung cancer. Radiomics—the extraction and analysis of quantitative features from imaging—can identify additional imaging characteristics that cannot be seen by the eye. These features can potentially be used to diagnose cancer, identify mutations, and predict prognosis in an accurate and noninvasive fash- ion. This article provides insights about trends in radiomics of lung cancer and challenges to widespread adoption.
    CONCLUSION. Radiomic studies are currently limited to a small number of cancer types. Its application across various centers are nonstandardized, leading to difficulties in comparing and generalizing results. The tools available to apply radiomics are specialized and limited in scope, blunting widespread use and clinical integration in the general population. Increasing the number of multicenter studies and consortiums and inclusion of radiomics in resident training will bring more attention and clarity to the growing field of radiomics.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • OBJECTIVE. Diagnostic imaging has traditionally relied on a limited set of qualitative imaging characteristics for the diagnosis and management of lung cancer. Radiomics—the extraction and analysis of quantitative features from imaging—can identify additional imaging characteristics that cannot be seen by the eye. These features can potentially be used to diagnose cancer, identify mutations, and predict prognosis in an accurate and noninvasive fashion. This article provides insights about trends in radiomics of lung cancer and challenges to widespread adoption.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • CONCLUSION. Radiomic studies are currently limited to a small number of cancer types. Its application across various centers are nonstandardized, leading to difficulties in comparing and generalizing results. The tools available to apply radiomics are specialized and limited in scope, blunting widespread use and clinical integration in the general population. Increasing the number of multicenter studies and consortiums and inclusion of radiomics in resident training will bring more attention and clarity to the growing field of radiomics.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Radiomics is defined as the quantification of the phenotypic features of a lesion from medical imaging (i.e., CT, PET, MRI, ultrasound). These features include lesion shape, volume, texture, attenuation, and many more that are not readily apparent or are too numerous for an individual radiologist to assess visually or qualitatively. In other words, radiomics is the process of creating a set of organized data based on the physical properties of an object of interest.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Regardless of lesion histology and location, the workflow in radiomics remains similar. Images of the lesion, typically CT images, are acquired. The images are segmented to define the outer limits of a given lesion. Specific phenotypic features are then selected, extracted from the images, and recorded. Finally, data analysis is performed on the recorded data. Image features can be extracted and analyzed in either 2D or 3D: 2D refers to segmentation and analysis of radiomic metrics on a single-slice image, whereas 3D refers to the same process across the entire volume of a tumor (many slices).
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Image features can be extracted and analyzed in either 2D or 3D: 2D refers to segmentation and analysis of radiomic metrics on a single-slice image, whereas 3D refers to the same process across the entire volume of a tumor (many slices). Therefore, 3D radiomics, by definition, requires analysis of the entire volume of tumor. In general, feature extraction and analysis are easier and faster in 2D than in 3D, but 3D may theoretically carry more information. Two-dimensional radiomics is used more commonly, but 3D radiomics is appealing with regard to analyzing intratumoral heterogeneity in cases in which different parts of a tumor may exhibit differing histologic subtypes.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “Segmentation of a lesion is the act of extracting or isolating a lesion of interest (e.g., lung nodule) from the surrounding normal lung. Features are then extracted and are further analyzed directly from the segmented lesion. This can be thought of in distinction to deep learning, where an algorithm must learn to automatically extract features from an unsegmented image.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Lesion segmentation can be done either manually or in an automated fashion. Manual segmentation—that is, segmentation performed by a trained observer who manually outlines the lesion of interest—is time-consuming and is more prone to interobserver variability and subjectivity than semiautomated and fully automated segmentation. Manual segmentation is important when accuracy of the tumor outline (i.e., lesion shape and size) is needed.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Shape is one of the feature categories understood as both semantic and agnostic. It is a category of features that includes diameter measurements (e.g., minimum, maximum) and their derivatives including volume, ratio of diameters, surface-to-volume ratio, and compactness. Diameter measurements and their derivatives are among the most commonly assessed features. Semantic descriptions such as round, oval, and spiculated are understood agnostically by a varied lexicon that attempts to determine how irregular the object is. In the shape category, tumor volume has shown the most promise in predicting treatment response.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “Texture in radiomics broadly refers to the variation in the gray-scale intensities of adjacent pixels or voxels in an image. Depending on the technique involved, texture features are categorized into first, second, and higher-order statistical measures. The first-order statistical measures are composed of features that account for variations in gray-scale intensities without accounting for their spatial location or orientation on the image. For example, a histogram of pixel or voxel intensities, which is a visual representation of the distribution of gray-scale intensity values on an image, is the most common technique to derive the first-order texture measures.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Second-order texture metrics encompass hundreds of features derived by evaluating the relationship of adjacent pixels in an ROI or across the entire lesion. These metrics account for both the intensity of a gray-scale value and its location or orientation in the image. CT images are formed from a 3D matrix of data that is used to determine the amount of gray-level color to display for a given image pixel. Texture or heterogeneity refers to analysis of adjacent pixels of gray color to determine the relationship between them; if there are wide variances in the amount of gray color in a given area, then a lesion is considered more heterogeneous or to have a coarse texture.
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “Texture has shown the most promise in predicting the presence of malignancy and prognosis. Local binary patterns (LBPs) and gray-level co-occurrence matrices (GLCMs) are most often used in this. However, evaluations of nodule heterogeneity or texture are not limited to LBPs or GLCMs. Numerous alternative methods that attempt to extract patterns from an image via a series of mathematic transformations or filters applied to the image, including Laws’ energy descriptors, fractal analysis, and wavelet analysis, are being increasing applied. This latter group of texture metrics includes higher-order statistical measures. Texture analysis has practical applications; for example, Parmar and colleagues showed that texture features in lung cancer were significantly associated with tumor stage and patient survival.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504

  • “Segmentation and feature recognition currently rely on the initial identification of a nodule by a radiologist. Thus, the near-term and medium-term role of radiomics is likely to be as a support tool in which radiomics is integrated with traditional radiologic and invasive histologic information. We should note that many prior studies achieved highest accuracy when radiomic data were viewed in light of genetic and clinical information.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “Most importantly, the study of radiomics must be drastically expanded to account for the numerous clinical and radiologic presentations of lung cancer. Radiomics is predicated on creating tools to more accurately diagnose lung cancer and determine prognosis of patients with lung cancer in a noninvasive fashion. However, the tools available to practice radiomics are specialized and limited in scope, blunting wide-spread use and clinical integration in the general population. Looking forward, we believe that increasing the number of multicenter studies and consortiums and inclusion of radiomics in resident training will bring more attention to the growing field of radiomics.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • “ Other challenges for radiomics include advancing interinstitutional standards for image acquisition and reconstruction parameters and the development of a unified lexicon. Radiomic data are affected by different image acquisition and reconstruction parameters (e.g., contrast timing, slice thickness, reconstruction algorithm, tube voltage, tube current, and so on) that can affect the reproducibility of radiomic features . Many radiomic studies have relied on a heterogeneous dataset of imaging using a mixture of these parameters. Standardized imaging parameters, including consistent contrast dose, timing, and radiation dose levels, will likely need to be implemented for radiomic studies.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • Furthermore, radiomics can be performed in 2D or 3D. Two-dimensional radiomics is applied to a single image slice, and the resulting radiomic features can vary from slice to slice. Three-dimensional radiomics is applied to the entire volume of a tumor. The potential differences between these two fundamentally different approaches require further evaluation. In addition, radiomics is a multidisciplinary field with experts from different backgrounds who approach radiomics in different ways. These experts often collaborate and have to understand and incorporate the methods and rationale of sometimes unfamiliar disciplines. For example, computer science researchers may have limited knowledge and experience with medical image acquisition and reconstruction. A unified lexicon will be necessary to maintain consistency, especially for researchers who have limited experience with medical imaging.”
    Radiomics in Pulmonary Lesion Imaging
    Hassani C et al.
    AJR 2019; 212:497–504
  • OBJECTIVE. The purpose of this study is to evaluate the potential value of machine learning (ML)–based high-dimensional quantitative CT texture analysis in predicting the mutation status of the gene encoding the protein polybromo-1 (PBRM1) in patients with clear cell renal cell carcinoma (RCC). CONCLUSION. ML-based high-dimensional quantitative CT texture analysis might be a feasible and potential method for predicting PBRM1 mutation status in patients with clear cell RCC.
    Radiogenomics in Clear Cell Renal Cell Carcinoma: Machine Learning–Based High-Dimensional Quantitative CT Texture Analysis in Predicting PBRM1 Mutation Status
    Burak Kocak et al.
    AJR 2019; 212:W55–W63
  • “Quantitative CT (QCT) texture analysis (TA) is an image processing method for measuring repetitive pixel or voxel gray-level patterns that may not be perceptible with the human eye. Several texture parameters can be produced by this method, which makes QCT TA high-dimensional. Although the field of high-dimensional QCT TA is still under development, the literature suggests that QCT TA can be used for characterizing lesions or tumors, predicting staging, nuclear grading, assessing the response to treatment, and predicting survival.”
    Radiogenomics in Clear Cell Renal Cell Carcinoma: Machine Learning–Based High-Dimensional Quantitative CT Texture Analysis in Predicting PBRM1 Mutation Status
    Burak Kocak et al.
    AJR 2019; 212:W55–W63
  • “Radiogenomics is a field of radiology in- vestigating the potential associations be- tween the imaging features of a disease and the underlying genetic patterns or molecular phenotype of that disease. The field has aimed to noninvasively obtain predictive data for diagnostic, prognostic, and, ultimately, optimal therapeutic assessment.”
    Radiogenomics in Clear Cell Renal Cell Carcinoma: Machine Learning–Based High-Dimensional Quantitative CT Texture Analysis in Predicting PBRM1 Mutation Status
    Burak Kocak et al.
    AJR 2019; 212:W55–W63
  • In conclusion, ML-based high-dimensional QCT TA is a feasible and potential method for predicting PBRM1 mutation status in patients with clear cell RCC. Nonetheless, more studies with more labeled data are absolutely required for further validation and improve- ment of the method for clinical use. We hope that the present study will provide the basis for new research.
    Radiogenomics in Clear Cell Renal Cell Carcinoma: Machine Learning–Based High-Dimensional Quantitative CT Texture Analysis in Predicting PBRM1 Mutation Status
    Burak Kocak et al.
    AJR 2019; 212:W55–W63
  • “Texture analysis has a potential role in distinguishing benign from malignant adrenal nodules on CECT and may decrease the need for additional imaging studies in the workup of incidentally discovered adrenal nodules.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Current imaging methods can diagnose lipid-rich adenomas with the use of either unenhanced CT or chemical-shift MRI and can diagnose lipid-poor adenomas on the basis of calculation of the percentage washout on contrast-enhanced CT (CECT).”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Image-based texture analysis is a quantitative technique that provides a measure of lesion heterogeneity on the basis of local variations in image brightness. First-order statistics- based texture analysis evaluates the number of pixels that have a particular gray-level value within a defined ROI. First-order texture analysis does not account for the location of the pixels within the ROI. Second-order statistics- based texture analysis evaluates the location and spatial interrelationship s between pixels of variable gray-level values.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • For example, first-order texture analysis can determine how many pixels have attenuation of 0 HU within an adrenal nodule. Second-order texture analysis can determine whether those pixels with an attenuation of 0 HU within an adrenal nodule are distributed evenly or are clustered in groups.
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Texture analysis of CECT images showed higher diagnostic performance for the diagnosis of malignancy, compared with CECT attenuation. The performance of select individual CECT texture features (long-run high gray-level emphasis, entropy, and short-run low gray-level emphasis) were comparable to unenhanced attenuation on CT and the SII on MRI, which are the standard diagnostic imaging tests used to distinguish adrenal adenomas from metastases in clinical practice.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • Increased tumor heterogeneity is the most likely reason for the ability of texture analysis to predict adrenal malignancy on CECT. As is seen in Figure 2, lipid-poor adenomas appeared homogeneous on CECT, compared with malignant lesions, which appeared heterogeneous. We speculate that the administration of contrast material may make lipid- poor adenomas appear more homogeneous because both lipid-rich and lipid-poor areas will have uptake of contrast medium.
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Malignant adrenal lesions become more heterogeneous after contrast material administration because of tumor angiogenesis and increased conspicuity of tumor necrosis. In support of our theory, a recent study by Sasaguri et al. showed that adrenal metastases from renal carcinoma showed visibly higher internal heterogeneity, compared with benign adrenal masses on CECT.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • Another limitation of the present study is the retrospective nature of the data acquisition. Because this is an observational study, the type of scanner used for each patient was not controlled. One cannot underestimate the potential impact of variation in CT and MR image quality on the results of texture analysis. This factor alone represents a major challenge when one considers the robustness of applying texture analysis in the clinical setting.
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “The introduction of radiomics has brought with it the vast expansion of the promise of quantitative and objective assessment of images. Interpretations are no longer limited to features like area, volume, and histogram-derived metrics; they can include hundreds of different features including shape, gray-level run-length matrices, Haralick texture, het- erogeneity, coarseness, or busyness.”
    How Can Radiomics Be Consistently Applied across Imagers and Institutions?
    Steiger P, Sood R
    Radiology (in press)
  • It allows for correction of radiomic measurements on the basis of their distribution and knowledge of covariates. The authors tested their method with one publicly available phantom data set and two patient data sets from patients with lung cancer. They convincingly showed that their method reduced im- ager-induced variability without sacrificing diagnostic sensitivity. Their article explains the method clearly and pro- vides all the references needed to replicate the work. This should encourage others to apply this method and test it in other radiomics studies and applications.
    How Can Radiomics Be Consistently Applied across Imagers and Institutions?
    Steiger P, Sood R
    Radiology (in press)
  • “In summary, the results of the present study indicate that the use of texture analysis for evaluation of adrenal nodules works best with CECT. This finding suggests that CT texture analysis may have a potential role in distinguishing benign lipid-poor ad- enomas from adrenal malignancy on single- phase CECT. Furthermore, the application of texture analysis may potentially decrease the need for additional imaging studies to workup incidentally discovered adrenal nodules.”
    Can Texture Analysis Be Used to Distinguish Benign From Malignant Adrenal Nodules on Unenhanced CT, Contrast-Enhanced CT, or In- Phase and Opposed-Phase MRI?
    Ho LM et al.
    AJR 2019; 212:554–561
  • “Radiomics holds the promise to become a tool at the disposal of the radiologist to expand the qualitative interpretation of the image, with additional quantitative information that can provide functional and prospective information not evident from the image alone. More studies are needed to fulfill this promise. The proposed algorithm has been shown to be effective in both thin- and thick-section CT images.”
    How Can Radiomics Be Consistently Applied across Imagers and Institutions?
    Steiger P, Sood R
    Radiology (in press)
  • “Therefore, the general success of radiomics in lung cancer and oncology will in part depend on the development and adoption of tailored image acquisition techniques for quantitative feature analysis. Radiomics will benefit from an extension of efforts already underway to standardize quantitative imaging, spearheaded by the Quantitative Imaging Biomarkers Alliance.”
    How Can Radiomics Be Consistently Applied across Imagers and Institutions?
    Steiger P, Sood R
    Radiology (in press)
  • ”Substantial hurdles remain until radiomics can become a routine tool in the radiology reading room of the future, as eloquently explained by Gillies et al. Among them is the need to validate any radiomics biomarkers in prospective multicenter studies. The variability introduced by the wide variety of avail- able equipment and imaging protocols must be controlled to allow these radiomic biomarkers to be used in a broader manner. The method presented by Orlhac et al. may have an important role in this research.”
    How Can Radiomics Be Consistently Applied across Imagers and Institutions?
    Steiger P, Sood R
    Radiology (in press)
Kidney

  • OBJECTIVE. The purpose of this study is to evaluate the potential value of machine learning (ML)–based high-dimensional quantitative CT texture analysis in predicting the mutation status of the gene encoding the protein polybromo-1 (PBRM1) in patients with clear cell renal cell carcinoma (RCC).
    CONCLUSION. ML-based high-dimensional quantitative CT texture analysis might be a feasible and potential method for predicting PBRM1 mutation status in patients with clear cell RCC.
    Radiogenomics in Clear Cell Renal Cell Carcinoma: Machine Learning–Based High-Dimensional Quantitative CT Texture Analysis in Predicting PBRM1 Mutation Status
    Burak Kocak et al.
    AJR 2019; 212:W55–W63
  • “Quantitative CT (QCT) texture analysis (TA) is an image processing method for measuring repetitive pixel or voxel gray-level patterns that may not be perceptible with the human eye. Several texture parameters can be produced by this method, which makes QCT TA high-dimensional. Although the field of high-dimensional QCT TA is still under development, the literature suggests that QCT TA can be used for characterizing lesions or tumors, predicting staging, nuclear grading, assessing the response to treatment, and predicting survival.”
    Radiogenomics in Clear Cell Renal Cell Carcinoma: Machine Learning–Based High-Dimensional Quantitative CT Texture Analysis in Predicting PBRM1 Mutation Status
    Burak Kocak et al.
    AJR 2019; 212:W55–W63
  • “Radiogenomics is a field of radiology in- vestigating the potential associations be- tween the imaging features of a disease and the underlying genetic patterns or molecular phenotype of that disease. The field has aimed to noninvasively obtain predictive data for diagnostic, prognostic, and, ultimately, optimal therapeutic assessment.”
    Radiogenomics in Clear Cell Renal Cell Carcinoma: Machine Learning–Based High-Dimensional Quantitative CT Texture Analysis in Predicting PBRM1 Mutation Status
    Burak Kocak et al.
    AJR 2019; 212:W55–W63
  • In conclusion, ML-based high-dimensional QCT TA is a feasible and potential method for predicting PBRM1 mutation status in patients with clear cell RCC. Nonetheless, more studies with more labeled data are absolutely required for further validation and improve- ment of the method for clinical use. We hope that the present study will provide the basis for new research.
    Radiogenomics in Clear Cell Renal Cell Carcinoma: Machine Learning–Based High-Dimensional Quantitative CT Texture Analysis in Predicting PBRM1 Mutation Status
    Burak Kocak et al.
    AJR 2019; 212:W55–W63
  • OBJECTIVE. The purpose of this article is to describe useful imaging features for differentiating angiomyolipoma (AML) subtypes from renal cell carcinoma subtypes.
    CONCLUSION. A newer radiologic classification of renal AML consists of fat-rich AML (≤ –10 HU), fat-poor AML (> –10 HU; tumor-to-spleen ratio < 0.71; signal intensity index, > 16.5%), and fat-invisible AML (> –10 HU; tumor-to-spleen ratio, > 0.71; signal intensity index, < 16.5%). Each subtype must be differentiated from the renal cell carcinoma subtype because of overlapping imaging features.
    Renal Angiomyolipoma Based on New Classification: How to Differentiate It From Renal Cell Carcinoma
    Byung Kwan Park
    AJR 2019; 212:582–588
  • “Song et al. [1] reported on a new radiologic classification of renal angiomyolipoma (AML) in which they classified the tumor into three subtypes: fat-rich AML, fat-poor AML, and fat-invisible AML. Each AML subtype is defined according to the amount of fat, which is quantified with CT or MRI. Fat-rich AML measures –10 HU or less at CT. Both fat-poor AML and fat-invisible AML measure more than –10 HU.”
    Renal Angiomyolipoma Based on New Classification: How to Differentiate It From Renal Cell Carcinoma
    Byung Kwan Park
    AJR 2019; 212:582–588
  • Fat-rich AML is defined as a lesion mea- suring –10 HU or less on unenhanced CT images .This subtype constitutes approximately 95% of renal AMLs. Almost all fat-rich AMLs are easily diagnosed with unenhanced CT alone because fat, a hallmark of AML, is clearly visualized.”
    Renal Angiomyolipoma Based on New Classification: How to Differentiate It From Renal Cell Carcinoma
    Byung Kwan Park
    AJR 2019; 212:582–588
  • “Approximately 5% of renal AMLs histo- logically have a small amount of fat and correspond to fat-poor AML or fat-invisible AML in the Song classification. Among small (< 4 cm) renal tumors, 4–13% are histologically confirmed as AML because imaging shows too little fat. Many authors have shown that AML with a small amount of fat is likely to have female predominance, small size, and a more homogeneous texture than RCC”
    Renal Angiomyolipoma Based on New Classification: How to Differentiate It From Renal Cell Carcinoma
    Byung Kwan Park
    AJR 2019; 212:582–588
  • Fat-rich AML should be differentiated from fat-containing RCC if this situation is rarely encountered. A small amount of fat relative to a large tumor, calcification, or necrosis is more suggestive of RCC than of AML. In exceptional cases, biopsy is recommended if these findings are detected.”
    Renal Angiomyolipoma Based on New Classification: How to Differentiate It From Renal Cell Carcinoma
    Byung Kwan Park
    AJR 2019; 212:582–588
  • “Fat-invisible AML should be differentiated from non–clear cell RCC. Both tumors tend to be hyperattenuating on unenhanced CT images, negative on chemical shift MR images, hypointense on T2- or fat- suppressed T2-weighted MR images, hyper- intense on DW images, and hypointense on ADC maps. Therefore, biopsy is necessary to differentiate these tumors.”
    Renal Angiomyolipoma Based on New Classification: How to Differentiate It From Renal Cell Carcinoma
    Byung Kwan Park
    AJR 2019; 212:582–588
  • CT or MRI features can provide clues for differentiating fat-rich AML from fat-con- taining RCC and fat-poor AML from clear cell RCC. Fat-invisible AML, however, is difficult to differentiate from non–clear cell RCC on the basis of CT or MRI features. Radiologists should not be reluctant to perform biopsy when lesion differentiation is not clear at CT or MRI.
    Renal Angiomyolipoma Based on New Classification: How to Differentiate It From Renal Cell Carcinoma
    Byung Kwan Park
    AJR 2019; 212:582–588
Musculoskeletal

  • PURPOSE: This study is designed to test the authors’ hypothesis that radiologists’ reports from multiple imaging centers performing a lumbar MRI examination on the same patient over a short period of time will have (1) marked variability in interpretive findings and (2) a broad range of interpretive errors.
    STUDY DESIGN: This is a prospective observational study comparing the interpretive findings reported for one patient scanned at 10 different MRI centers over a period of 3 weeks to each other and to reference MRI examinations performed immediately preceding and following the 10 MRI examinations.
    PATIENT SAMPLE: The sample is a 63-year-old woman with a history of low back pain and right L5 radicular symptoms.
  • RESULTS: Across all 10 study examinations, there were 49 distinct findings reported related to the presence of a distinct pathology at a specific motion segment. Zero interpretive findings were reported in all 10 study examinations and only one finding was reported in nine out of 10 study examinations. Of the interpretive findings, 32.7% appeared only once across all 10 of the study examinations’ reports.
  • CONCLUSIONS: This study found marked variability in the reported interpretive findings and a high prevalence of interpretive errors in radiologists’ reports of an MRI examination of the lumbar spine performed on the same patient at 10 different MRI centers over a short time period. As a result, the authors conclude that where a patient obtains his or her MRI examination and which radiologist in- terprets the examination may have a direct impact on radiological diagnosis, subsequent choice of treatment, and clinical outcome.
Pancreas

  • ”The octreoscan is 70%-95% sensitive for detecting PNETs with somatostatin receptors. However, not all PNETs have somatostatin receptors; therefore, a negative octreotide scan does not rule out PNETs. In addition, lymphocytes can also display somatostatin receptors on their surface and cause uptake of the radiolabeled analog creating a false positive. One of the two IPAS patients in our series had a false positive octreotide scan; this displays the challenges that persist in diagnosing incidental pancreatic lesions.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “Diagnosis of incidental distal pancreatic solid lesions like IPAS creates significant difficulty for pancreas surgeons. Our algorithm provides needed structure to the work up. Although this is designed to rule out IPAS, this algorithm can be used as a starting point for the work up of any incidentally found pancreatic mass. In the past, the work up of incidentally found lesions led to the development of useful guidelines in the adrenal gland. Therefore, establishment of protocols like the one proposed for pancreatic lesions may aid in the development of future guidelines for the pancreas.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “Work up of an incidental pancreatic solid lesion remains a challenge, especially for the diagnosis of IPAS. Successful diagnosis will require a strong index of suspicion, a multi- disciplinary approach, and the use of the proposed algorithm. In time, this may aid clinicians in the distinction between benign IPAS, which requires no further action and a lesion requiring resection.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • Background: Identification of incidental pancreatic lesions is increasing because of advancements in imaging. Diagnosis remains a challenge for clinicians, with intrapancreatic accessory spleens (IPAS) posing a unique dilemma. IPAS are frequently resected because of inability to exclude alternate diagnoses, subjecting patients to unnecessary risk. The purpose of this study was to examine our institutional experience with IPAS and develop a multidisciplinary algorithm to improve preoperative diagnosis.
    Conclusions: Incidental pancreatic lesions like IPAS remain a diagnostic challenge for clinicians. Employing a diagnostic algorithm as proposed may aid in the distinction of malignant and premalignant pathology and prevent unwarranted pancreatic resections.
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “Ten patients of 303 patients who underwent a distal pancreatectomy were identified with a final pathology of IPAS. The average age was 54 y, 80% were white, and 60% were male. Lesions ranged in size from 7 mm to 5.1 cm in largest diameter (mean 2.2 cm). Lesions were described as round, well-marginated, and enhancing masses within the pancreatic tail. Preoperative workup was variable in terms of imaging and laboratory testing. Diagnostic workups were examined and combined with multidisciplinary input to create a diagnostic algorithm.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “IPAS are the result of splenic tissue buds failing to fuse during embryologic development and are quite common, found in 10%-20% of individuals. Accessory splenic tissue is usually asymptomatic and found incidentally with the most common location in the splenic hilum. However, 10%-15% are found in the pancreatic tail where they pose a diagnostic predicament.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • On CT, IPAS appears as solid heteroge- neously enhancing masses, size averages 1-3 cm, and most commonly within 3 cm of the tail of the pancreas. Similarly, 90% of our patients had an enhancing distal mass with a mean maximum diameter less than 3 cm. The attenuation of accessory splenic tissue is similar to the spleen on arterial and venous phases, which was commented on in only two of the initial CT reports.
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “The heterogeneous enhancement on arterial phase is secondary to the differences in rate of blood flow between the red pulp and the white pulp of the spleen. Nonfunctioning PNETs are also hyperenhancing lesions on CT but with uniform or ring-like enhancement and greater enhancement on the venous phase.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “Metastatic disease represents 2%-5% of all malignant pancreatic tumors and usually arises from renal cell carcinoma, non-small cell lung cancer, and gastrointestinal carcinoma. Renal cell carcinoma usually presents as an enhancing lesion, whereas the other two are usually hypoattenuating but all typically correlate with the discovery of a primary tumor on CT.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
Practice Management

  • PURPOSE: This study is designed to test the authors’ hypothesis that radiologists’ reports from multiple imaging centers performing a lumbar MRI examination on the same patient over a short period of time will have (1) marked variability in interpretive findings and (2) a broad range of interpretive errors.
    STUDY DESIGN: This is a prospective observational study comparing the interpretive findings reported for one patient scanned at 10 different MRI centers over a period of 3 weeks to each other and to reference MRI examinations performed immediately preceding and following the 10 MRI examinations.
    PATIENT SAMPLE: The sample is a 63-year-old woman with a history of low back pain and right L5 radicular symptoms.
  • RESULTS: Across all 10 study examinations, there were 49 distinct findings reported related to the presence of a distinct pathology at a specific motion segment. Zero interpretive findings were reported in all 10 study examinations and only one finding was reported in nine out of 10 study examinations. Of the interpretive findings, 32.7% appeared only once across all 10 of the study examinations’ reports.
  • CONCLUSIONS: This study found marked variability in the reported interpretive findings and a high prevalence of interpretive errors in radiologists’ reports of an MRI examination of the lumbar spine performed on the same patient at 10 different MRI centers over a short time period. As a result, the authors conclude that where a patient obtains his or her MRI examination and which radiologist in- terprets the examination may have a direct impact on radiological diagnosis, subsequent choice of treatment, and clinical outcome.
Small Bowel

  • “Systemic lupus erythematosus is an autoimmune disease caused by immune complex deposition that classically affects young women. The disease process often involves the joints, kidneys, gastrointestinal tract, and skin. Lupus may affect vasculature of the entire gastrointestinal tract, but the SMA distribution is involved most commonly. Polyarteritis nodosa is a medium-vessel fibrinoid necrotizing vasculitis that occurs in middle-aged to older adults. Classically, it causes microaneurysms and erosion of the arterial wall, most commonly affecting the kidneys, gastrointestinal tract, and liver.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • Segmental arterial mediolysis is a nonatherosclerotic and noninflammatory arteriopathy characterized by lysis of the smooth muscle of the outer media that results in dissecting aneurysms and intramural hematomas. Unlike those of most vasculitis's, inflammatory or immune markers are most often normal. Middle-aged and elderly patients are affected most commonly and can present with abdominal pain, distention, decreased hemoglobin level, bowel ischemia, or shock. Imaging findings of segmental arterial mediolysis are similar to those of other vasculitis's, although it classically results in alternating aneurysm and stenosis of the abdominal splanchnic arteries, without involvement of other vessels.
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “CT angiographic findings of vasculitis include circumferential arterial wall thickening, luminal narrowing, and microaneurysms. Long-segment smooth tapering without evidence of atherosclerotic disease usually is seen in vasculitis. A beaded appearance of the SMA may be seen with multiple aneurysms. The extent of the disease must be detailed, because focal disease can be managed with surgical or endovascular treatment, and diffuse disease is managed medically.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • Colonic diverticulosis and angiodysplasia can be differentiated readily at multidetector CT, which is of prognostic importance, because bleeding recurs in up to 85% of untreated patients with angiodysplasia, while only 25% of untreated diverticular patients experience recurrent bleeding.
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Neurofibromatosis type 1 (NF1) is one of the most fascinating and common human mendelian disorders, affecting approximately one in 3000 persons. From the initial artist renderings of patients with NF1 in the 15th century and the earliest medical reports in 18th century, to the complex molecular genetic studies of the late 20th century, physicians and lay persons alike have been fascinated with this disease because of its diverse manifestations and the unusual and bizarre physical appearances associated with the disease.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “NF1 belongs to a group of disorders referred to as phakomatoses. These disorders (NF1, neurofibromatosis type 2, tuberous sclerosis, Sturge-Weber syndrome, and neurocutaneous melano- sis) have selective involvement of tissues of ectodermal origin (central nervous system, eye, and skin). All of these disorders, with the exception of Sturge-Weber syndrome, have an autosomal dominant inheritance pattern.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “The superior mesenteric artery (SMA) provides vital blood supply to the midgut, and an acute abnormality can rapidly precipitate bowel ischemia and infarction and lead to morbidity and mortality. Vascular diseases that acutely compromise the SMA threaten its tributaries and include occlusion, dissection, aneurysm rupture, pseudoaneurysm, vasculitis, and SMA branch hemorrhage into the bowel.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vascular diseases that acutely compromise the SMA and threaten its tributaries include occlusion, dissection, aneurysm rupture, pseudoaneurysm, vasculitis, and SMA branch hemorrhage into the bowel. Clinical evaluation and imaging are both essential to determine whether a patient should be treated conservatively or requires a surgical or interventional procedure."
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • Within the mesenteric root, the SMA branches into approximately four to six jejunal and nine to 13 ileal arteries arising on the left side. The right-sided branches include the middle colic, right colic, and ileocolic arteries . The branching pattern of the colonic arteries often varies, although the middle colic artery commonly arises from the proximal SMA, and the ileocolic artery represents the terminal branch. The SMA provides blood supply from the ampullary region of the second portion of the duodenum to the distal transverse colon near the splenic flexure."
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “An acute arterial embolus is the main cause (40%–50%) followed by arterial thrombosis (15%–30%) , mesenteric venous thrombosis (20%), and nonocclusive mesenteric ischemia (10%–20%). Embolic material originating from the heart is usually lodged in the SMA a few centimeters distal to the origin, near the location of the middle colic artery origin. Smaller emboli can travel farther and occlude more distal branches. In comparison, thrombosis secondary to rupture of an unstable atherosclerotic plaque often occurs in the proximal 2 cm of the SMA. Nonocclusive ischemia occurs in patients with hypotension, such as those with cardiogenic shock and hypoperfusion, which result in severe mesenteric vasoconstriction. “
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Visualization of a proximal segment with arterial wall thickening and calcification is diagnostic of a preexisting atherosclerotic plaque that likely ruptured to cause complete occlusion. A distal occlusion near the origin of the middle colic artery likely represents a dislodged clot from the heart, commonly in a patient with atrial fibrillation. Diffuse narrowing of the SMA and branches without focal occlusion is suggestive of nonocclusive mesenteric ischemia.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT. "
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “In the emergency setting, it is critical to identify the radiologic findings that represent severe ischemia, which is associated with higher morbidity, and for which surgical treatment with exploratory laparotomy and resection of the bowel is likely necessary. The presence of pneumatosis, or gas in the bowel wall, is a concerning finding that raises the possibility of transmural infarction. Locules of gas may track into mesenteric veins and the portal vein (1). A frank pneumoperitoneum indicates a bowel perforation secondary to transmural wall necrosis. Severe ischemia with transmural infarction also can be seen as mesenteric fat stranding and ascites.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ”In a hemodynamically stable patient who presents early with favorable vascular and bowel CT findings, endovascular treatment may be the best option. In a meta-analysis, Salsano et al evaluated and compared the outcomes of seven studies and showed that endovascular therapy had better outcomes, with significantly lower mortality and bowel resection.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ” Certain multidetector CT findings must be considered in planning an intervention and should be detailed in the CT interpretation. Placing a stent for proximal SMA stenosis most commonly due to calcified atherosclerotic disease is best achieved with a noncovered balloon-expandable stent as opposed to a self- expandable nitinol stent. In this scenario, the rigidity and hoop-strength of the balloon-expandable stent make it better at preventing elastic recoil from the atherosclerotic plaque. However, self-expandable stents are often placed in distal stenosis of SMA branches, because they are generally more flexible and more likely to accommodate greater vessel tortuosity.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ” Diagnosis.—SMA dissection can be divided into two groups: spontaneous isolated and combined. Spontaneous isolated SMA dissection (SISMAD) is SMA dissection that occurs without aortic dissection . Combined SMA dissection is more common and is due to an aortic dissection flap extending into the proximal vessel. SISMAD is a rare disease, although it is being identified more often with the use of CT angiography. An increased incidence of SISMAD has been described in men and patients aged 50–70 years old. Dissection is the result of blood entering the media of an artery through an intimal defect and creating a true lumen in continuity with the unaffected aorta and a false lumen.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “SMA aneurysms account for 5.5% of all visceral artery aneurysms and are the third most common type. They occur predominantly in men and in the 5th decade of life. SMA aneurysms are associated with substantial morbidity, because they put the patient at risk for rupture and hemorrhage. Approximately 38%–50% of patients present with rupture, and mortality rates range from 40% to 60%. The majority of aneurysms occur in the proximal 5 cm of the SMA.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “There are several causes of aneurysms including atherosclerosis, trauma, surgery, inflammation and/or vasculitis, infection, and collagen vascular disorders. Most commonly, SMA aneurysms are asymptomatic and are found incidentally at imaging. Patients may present with colicky abdominal pain or rarely a pulsatile mass. Patients who present with a rupture have signs of hemodynamic compromise. SMA aneurysms must be identified and characterized by the radiologist to give the emergency medicine physician and vascular interventional radiologist the opportunity to treat appropriately.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vasculitis refers to inflammation of the blood vessel walls and includes a diverse group of conditions. Some of the vasculitis's may involve the SMA. Up to 50% of cases of vasculitis involve the mesenteric arteries, but only 16% manifest as isolated mesenteric disease. The pathogenesis of vasculitis varies with each type and can include cell-mediated, immune complex–mediated, and antineutrophil cytoplasmic antibody–mediated inflammation.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Segmental arterial mediolysis is a nonatherosclerotic and noninflammatory arteriopathy characterized by lysis of the smooth muscle of the outer media that results in dissecting aneurysms and intramural hematomas. Unlike those of most vasculitis's, inflammatory or immune markers are most often normal. Middle-aged and elderly patients are affected most commonly and can present with abdominal pain, distention, decreased hemoglobin level, bowel ischemia, or shock. Imaging findings of segmental arterial mediolysis are similar to those of other vasculitis's, although it classically results in alternating aneurysm and stenosis of the abdominal splanchnic arteries, without involvement of other vessel.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vasculitis refers to inflammation of the blood vessel walls and includes a diverse group of conditions. Some of the vasculitis's may involve the SMA. Up to 50% of cases of vasculitis involve the mesenteric arteries, but only 16% manifest as isolated mesenteric disease. The pathogenesis of vasculitis varies with each type and can include cell-mediated, immune complex–mediated, and antineutrophil cytoplasmic antibody–mediated inflammation.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Although the small intestine accounts for over 90% of the surface area of the alimentary tract, tumors of the small intestine represent less than 5% of all gastrointestinal tract neoplasms. Common small bowel tumors typically are well evaluated with cross-sectional imaging modalities such as CT and MR, but accurate identification and differentiation can be challenging. Differentiating normal bowel from abnormal tumor depends on imaging modality and the particular technique.”
    Multimodality imaging of small bowel neoplasms.
    Williams EA1, Bowman AW2
    Abdom Radiol (NY). 2019 (in press)
  • “Differentiating normal bowel from abnormal tumor depends on imaging modality and the particular technique. While endoscopic evaluation is typically more sensitive for the detection of intraluminal tumors that can be reached, CT and MR, as well as select nuclear medicine studies, remain superior for evaluating extraluminal neoplasms. Understanding the imaging characteristics of typical benign and malignant small bowel tumors is critical, because of overlapping features and associated secondary complications.”
    Multimodality imaging of small bowel neoplasms.
    Williams EA, Bowman AW
    Abdom Radiol (NY). 2019 (in press)
  • Small Bowel GIST Tumors
    - Most common primary mesenchymal tumor of GI tract
    - Usually seen in patients > 40 years of age
    - Variable in size and appearance, often well-circumscribed
    - May calcify, often exophytic
    - Enhancement may be homogeneous or heterogeneous
  • “GIST is the most common mesenchymal neoplasm of the gastrointestinal tract, including both benign and malignant varieties, and they are most commonly seen in patients over 40 years of age. They occur throughout the small bowel, classically as a well-marginated mass of variable size. Though they begin as mural masses, they can protrude into the lumen or grow exophytically. When presenting as an extraserosal mass, identifying the origin can be challenging.”
    Multimodality imaging of small bowel neoplasms.
    Williams EA, Bowman AW
    Abdom Radiol (NY). 2019 (in press)
  • Small Bowel GIST: Pearls
    - Tumors can be very large and markedly exophytic, with a heterogeneous appearance on CT and MR because of hemorrhage and necrosis. 
    - Calcification sometimes occurs, similar to leiomyoma 
    - These tumors are often hypervascular following IV contrast administration and can be hypermetabolic on PET imaging
  • ”Malignant GISTs can present with metastases to the liver, omentum, and peritoneum. Lymphatic spread and retraction of the mesentery are unusual features compared to other malignancies affecting the small bowel. Recurrent disease following surgical resection is not uncommon in the setting of malignant GIST”.
    Multimodality imaging of small bowel neoplasms.
    Williams EA, Bowman AW
    Abdom Radiol (NY). 2019 (in press)
  • ” Malignant GISTs can present with metastases to the liver, omentum, and peritoneum. Lymphatic spread and retraction of the mesentery are unusual features compared to other malignancies affecting the small bowel. Recurrent disease following surgical resection is not uncommon in the setting of malignant GIST ”.
    Multimodality imaging of small bowel neoplasms.
    Williams EA, Bowman AW
    Abdom Radiol (NY). 2019 (in press)
  • “This case series reveals an important significant association between heterogeneous enhancement and non-low risk (ie, moderate/high) SB-GISTs. Beyond just describing the tumor, using enhancing pattern, the interpreting radiologist can preoperatively suggest additional prognostic information, potentially helpful for surgical planning.”
    Small Bowel Gastrointestinal Stromal Tumors: Multidetector Computed Tomography Enhancement Pattern and Risk of Progression
    Verde F, Hruban RH, Fishman EK  
    Comput Assist Tomogr. 2017 May/Jun;41(3):407-411. 
  • “Small bowel cancers are very rare despite the length and large mucosal surface of the small bowel and account for 3% to 6% of all gastroin- testinal (GI) tract malignancies. Adenocarcinoma, neuroendocrine neoplasms, lymphoma, and GI stromal tumors (GISTs) are the most prevalent primary small bowel cancers, with adenocarcinoma and neuroendocrine neoplasms accounting for nearly two-thirds of small bowel cancers.”
    Imaging and Screening of Cancer of the Small Bowel
    Jin Sil Kim et al.
    Radiol Clin N Am (2017) (in press)
  • “A variety of conditions increase the risk of small bowel GISTs. Familial GIST is autosomal dominant and often leads to the development of a single or multiple GISTs in middle age. Additionally, about 5% of patients with neurofibromatosis type 1 (NF-1) will present with a small bowel GIST; GISTs can be seen in young females as part of the Carney triad (gastric or small bowel GIST, pulmonary chondroma, and extra-adrenal pheochromocytoma) or in males or females as part of the Carney-Stratakis syndrome (GIST and paraganglioma).”
    Imaging and Screening of Cancer of the Small Bowel
    Jin Sil Kim et al.
    Radiol Clin N Am (2017) (in press)
  • Small Bowel GIST Tumors: Facts
    - Most common mesenchymal tumor of the gastrointestinal tract. 
    - Increased incidence in NF-1 patients
    - Most common in the stomach followed by small bowel
    - May present as GI bleed when the lesions are smaller and the tumor very vascular
    - Larger tumors are usually of higher grade than smaller tumors
  • GIST Tumors of the Small Bowel: Clinical Presentation
    - bowel obstruction
    - intraluminal GI bleeding (occult or frank) from mucosal ulceration
    - intraperitoneal bleeding secondary to rupture
  • Small Bowel Tumors: CT Attenuation
  • “They are typically well-circumscribed tumors and usually arise from the muscularis propria of the gastrointestinal tract. The classic tendency is for exophytic growth, especially since they arise from the outer muscular layer. There is usually some growth towards the lumen however, as up to 50% of GISTs will exhibit mucosal ulceration on the luminal surface.”
    Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
    Scola D, Bahoura L, Copelan A. et al.
    Abdom Radiol (2017) 42: 1350-1364
  • “The size of tumors is highly variable, ranging from several millimeters to greater than 30 cm; the median tumor size for those considered high-risk (e.g., locally advanced primary tumor or metastatic/recurrent tumor) is reported as 8.9 cm .”
    Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
    Scola D, Bahoura L, Copelan A. et al.
    Abdom Radiol (2017) 42: 1350-1364
  • “Up to 30% of GISTs have poor prognostic factors including size >5 cm, lobulated contour, heterogeneous enhancement, presence of mesenteric fat infiltration, ulceration, regional lymphadenopathy or an exophytic growth pattern on CT .”
    Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
    Scola D, Bahoura L, Copelan A. et al.
    Abdom Radiol (2017) 42: 1350-1364
  • “They most commonly arise in the stomach (approximately 60%), followed by the jejunum/ileum (30%), duodenum (5%), colon (4%), and esophagus or appendix (1%). Even more rare are primary extra-intestinal locations. Clinical presentations are highly variable and usually dependent on tumor size and location .”
    Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
    Scola D, Bahoura L, Copelan A. et al.
    Abdom Radiol (2017) 42: 1350-1364
  • “GISTs occurring in the duodenum and remainder of the small bowel can also demonstrate any growth pattern but are commonly exophytic, possibly explained by slow growth and often delayed presentations. Calcifications are uncommon but can occasionally be present within larger GISTs. When large, enhancement is often heterogeneous, and there can be large hypo-attenuating necrotic components. They can also be arterially hyper-enhancing.”
    Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
    Scola D, Bahoura L, Copelan A. et al.
    Abdom Radiol (2017) 42: 1350-1364
  • “If a tumor is larger than 5 cm, and if removal would result in excessive damage to surrounding structures, it is typically considered unresectable. In these instances, treatment with targeted therapy (such as imatinib mesylate) is performed. Because mutational activation of TK receptors (KIT or PDGFRA) stimulates growth, targeted therapy agents are tyrosine kinase inhibitors, selectively blocking the GIST’s growth signal. Targeted therapy after surgical resection has become the standard of care to help prevent recurrence or treat recurrence or metastatic disease.”
    Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
    Scola D, Bahoura L, Copelan A. et al.
    Abdom Radiol (2017) 42: 1350-1364
  • “Imaging evaluation of GISTs tumors using rapid reduction in size to indicate treatment response to target therapies can be used as in the Response Evaluation Criteria in Solid Tumors (RECIST) criteria . In these instances rapid decrease in tumor size and number of lesions has been described. However size criteria alone underestimates/misinterprets good response, as stable or initially increasing size has been described . FDG PET can increase accuracy of RECIST criteria by showing decreasing FDG-avidity over time.”
    Getting the GIST: a pictorial review of the various patterns of presentation of gastrointestinal stromal tumors on imaging
    Scola D, Bahoura L, Copelan A. et al.
    Abdom Radiol (2017) 42: 1350-1364
  • “The most frequent clinical indication for imaging, which led to detection of the small bowel GISTs in our series, was suspected small bowel bleeding (45/111; 40.5%), with 34/45 of these patients having (75.5%) overt and 11/45 (24.5%) having occult small bowel bleeding. Abdominal pain was the indication for imaging in slightly over one-third of patients (41/111; 37%), with cancer surveillance in asymptomatic patients accounting for 9% (10/111) and clinical suspicion for potential small bowel tumor in 13% (15/111).”
    Impact of CT enterography on the diagnosis of small bowel gastrointestinal stromal tumors
    Vasconcelos, R.N., Dolan, S.G., Barlow, J.M. et al.
    Abdom Radiol May 2017, Volume 42, Issue 5, pp 1365–1373
  • “The association of gastrointestinal stromal tumors with NF1 has been recently recognized in the medical literature. In all reports to date, the gastrointestinal stromal tumors occurring in patients with NF1 are located in the small intes- tine and are multiple or occur in association with other intestinal neoplasms. Abdominal pain and bleeding are the most common presenting symptoms.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “Gastrointestinal stromal tumors associated with NF1 are histologically and immunophenotypically identical to those that occur in patients without NF1. The distinguishing features of gastrointestinal stromal tumors in NF1 are their predominant location in the small intestine and their tendency for multiplicity. Gastrointestinal stromal tumors arise in or near the muscularis propria of the gastrointestinal tract wall and may have intramural, intraluminal, or extraluminal growth.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • The biologic behavior of gastrointestinal stromal tumors in patients with NF1 does not appear to be different than that of such tumors in patients without NF1. The tumors may be benign, be malignant, or have uncertain malignant potential based on the current understanding of gastrointestinal stromal tumors.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “On CT and MR images, the tumors are heterogeneously enhancing masses with focal areas of cystic change or evidence of hemorrhage. The tumors have an intramural location and may extend intraluminally, simulating a polypoid mass, or exophytically into the adjacent mes- entery.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “Although the small intestine accounts for over 90% of the surface area of the alimentary tract, tumors of the small intestine represent less than 5% of all gastrointestinal tract neoplasms. Common small bowel tumors typically are well evaluated with cross-sectional imaging modalities such as CT and MR, but accurate identification and differentiation can be challenging. Differentiating normal bowel from abnormal tumor depends on imaging modality and the particular technique. While endoscopic evaluation is typically more sensitive for the detection of intraluminal tumors that can be reached, CT and MR, as well as select nuclear medicine studies, remain superior for evaluating extraluminal neoplasms. Understanding the imaging characteristics of typical benign and malignant small bowel tumors is critical, because of overlapping features and associated secondary complications.”
    Multimodality imaging of small bowel neoplasms.
    Williams EA1, Bowman AW2
    Abdom Radiol (NY). 2019 (in press)
Spleen

  • Background: Identification of incidental pancreatic lesions is increasing because of advancements in imaging. Diagnosis remains a challenge for clinicians, with intrapancreatic accessory spleens (IPAS) posing a unique dilemma. IPAS are frequently resected because of inability to exclude alternate diagnoses, subjecting patients to unnecessary risk. The purpose of this study was to examine our institutional experience with IPAS and develop a multidisciplinary algorithm to improve preoperative diagnosis.
    Conclusions: Incidental pancreatic lesions like IPAS remain a diagnostic challenge for clinicians. Employing a diagnostic algorithm as proposed may aid in the distinction of malignant and premalignant pathology and prevent unwarranted pancreatic resections.
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “Ten patients of 303 patients who underwent a distal pancreatectomy were identified with a final pathology of IPAS. The average age was 54 y, 80% were white, and 60% were male. Lesions ranged in size from 7 mm to 5.1 cm in largest diameter (mean 2.2 cm). Lesions were described as round, well-marginated, and enhancing masses within the pancreatic tail. Preoperative workup was variable in terms of imaging and laboratory testing. Diagnostic workups were examined and combined with multidisciplinary input to create a diagnostic algorithm.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “IPAS are the result of splenic tissue buds failing to fuse during embryologic development and are quite common, found in 10%-20% of individuals. Accessory splenic tissue is usually asymptomatic and found incidentally with the most common location in the splenic hilum. However, 10%-15% are found in the pancreatic tail where they pose a diagnostic predicament.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens Baugh KA et al. J Surg Res. 2019 Apr;236:144-152
  • On CT, IPAS appears as solid heteroge- neously enhancing masses, size averages 1-3 cm, and most commonly within 3 cm of the tail of the pancreas. Similarly, 90% of our patients had an enhancing distal mass with a mean maximum diameter less than 3 cm. The attenuation of accessory splenic tissue is similar to the spleen on arterial and venous phases, which was commented on in only two of the initial CT reports.
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “The heterogeneous enhancement on arterial phase is secondary to the differences in rate of blood flow between the red pulp and the white pulp of the spleen. Nonfunctioning PNETs are also hyperenhancing lesions on CT but with uniform or ring-like enhancement and greater enhancement on the venous phase.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “Metastatic disease represents 2%-5% of all malignant pancreatic tumors and usually arises from renal cell carcinoma, non-small cell lung cancer, and gastrointestinal carcinoma. Renal cell carcinoma usually presents as an enhancing lesion, whereas the other two are usually hypoattenuating but all typically correlate with the discovery of a primary tumor on CT.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • ”The octreoscan is 70%-95% sensitive for detecting PNETs with somatostatin receptors. However, not all PNETs have somatostatin receptors; therefore, a negative octreotide scan does not rule out PNETs. In addition, lymphocytes can also display somatostatin receptors on their surface and cause uptake of the radiolabeled analog creating a false positive. One of the two IPAS patients in our series had a false positive octreotide scan; this displays the challenges that persist in diagnosing incidental pancreatic lesions.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “Diagnosis of incidental distal pancreatic solid lesions like IPAS creates significant difficulty for pancreas surgeons. Our algorithm provides needed structure to the work up. Although this is designed to rule out IPAS, this algorithm can be used as a starting point for the work up of any incidentally found pancreatic mass. In the past, the work up of incidentally found lesions led to the development of useful guidelines in the adrenal gland. Therefore, establishment of protocols like the one proposed for pancreatic lesions may aid in the development of future guidelines for the pancreas.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
  • “Work up of an incidental pancreatic solid lesion remains a challenge, especially for the diagnosis of IPAS. Successful diagnosis will require a strong index of suspicion, a multi- disciplinary approach, and the use of the proposed algorithm. In time, this may aid clinicians in the distinction between benign IPAS, which requires no further action and a lesion requiring resection.”
    Pancreatic Incidentalomas: A Management Algorithm for Identifying Ectopic Spleens
    Baugh KA et al.
    J Surg Res. 2019 Apr;236:144-152
Syndromes in CT

  • “Neurofibromatosis type 1 (NF1) is one of the most fascinating and common human mendelian disorders, affecting approximately one in 3000 persons. From the initial artist renderings of patients with NF1 in the 15th century and the earliest medical reports in 18th century, to the complex molecular genetic studies of the late 20th century, physicians and lay persons alike have been fascinated with this disease because of its diverse manifestations and the unusual and bizarre physical appearances associated with the disease.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “NF1 belongs to a group of disorders referred to as phakomatoses. These disorders (NF1, neurofibromatosis type 2, tuberous sclerosis, Sturge-Weber syndrome, and neurocutaneous melano- sis) have selective involvement of tissues of ectodermal origin (central nervous system, eye, and skin). All of these disorders, with the exception of Sturge-Weber syndrome, have an autosomal dominant inheritance pattern.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “The association of gastrointestinal stromal tumors with NF1 has been recently recognized in the medical literature. In all reports to date, the gastrointestinal stromal tumors occurring in patients with NF1 are located in the small intes- tine and are multiple or occur in association with other intestinal neoplasms. Abdominal pain and bleeding are the most common presenting symptoms.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “Gastrointestinal stromal tumors associated with NF1 are histologically and immunophenotypically identical to those that occur in patients without NF1. The distinguishing features of gastrointestinal stromal tumors in NF1 are their predominant location in the small intestine and their tendency for multiplicity. Gastrointestinal stromal tumors arise in or near the muscularis propria of the gastrointestinal tract wall and may have intramural, intraluminal, or extraluminal growth.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • The biologic behavior of gastrointestinal stromal tumors in patients with NF1 does not appear to be different than that of such tumors in patients without NF1. The tumors may be benign, be malignant, or have uncertain malignant potential based on the current understanding of gastrointestinal stromal tumors.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
  • “On CT and MR images, the tumors are heterogeneously enhancing masses with focal areas of cystic change or evidence of hemorrhage. The tumors have an intramural location and may extend intraluminally, simulating a polypoid mass, or exophytically into the adjacent mes- entery.”
    Abdominal Neoplasms in Patients with Neurofibromatosis Type 1: Radiologic-Pathologic Correlation
    Angela D. Levy et al.
    RadioGraphics 2005; 25:455– 480
Vascular

  • “The superior mesenteric artery (SMA) provides vital blood supply to the midgut, and an acute abnormality can rapidly precipitate bowel ischemia and infarction and lead to morbidity and mortality. Vascular diseases that acutely compromise the SMA threaten its tributaries and include occlusion, dissection, aneurysm rupture, pseudoaneurysm, vasculitis, and SMA branch hemorrhage into the bowel.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vascular diseases that acutely compromise the SMA and threaten its tributaries include occlusion, dissection, aneurysm rupture, pseudoaneurysm, vasculitis, and SMA branch hemorrhage into the bowel. Clinical evaluation and imaging are both essential to determine whether a patient should be treated conservatively or requires a surgical or interventional procedure."
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • Within the mesenteric root, the SMA branches into approximately four to six jejunal and nine to 13 ileal arteries arising on the left side. The right-sided branches include the middle colic, right colic, and ileocolic arteries . The branching pattern of the colonic arteries often varies, although the middle colic artery commonly arises from the proximal SMA, and the ileocolic artery represents the terminal branch. The SMA provides blood supply from the ampullary region of the second portion of the duodenum to the distal transverse colon near the splenic flexure."
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “An acute arterial embolus is the main cause (40%–50%) followed by arterial thrombosis (15%–30%) , mesenteric venous thrombosis (20%), and nonocclusive mesenteric ischemia (10%–20%). Embolic material originating from the heart is usually lodged in the SMA a few centimeters distal to the origin, near the location of the middle colic artery origin. Smaller emboli can travel farther and occlude more distal branches. In comparison, thrombosis secondary to rupture of an unstable atherosclerotic plaque often occurs in the proximal 2 cm of the SMA. Nonocclusive ischemia occurs in patients with hypotension, such as those with cardiogenic shock and hypoperfusion, which result in severe mesenteric vasoconstriction. “
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Visualization of a proximal segment with arterial wall thickening and calcification is diagnostic of a preexisting atherosclerotic plaque that likely ruptured to cause complete occlusion. A distal occlusion near the origin of the middle colic artery likely represents a dislodged clot from the heart, commonly in a patient with atrial fibrillation. Diffuse narrowing of the SMA and branches without focal occlusion is suggestive of nonocclusive mesenteric ischemia.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “In the emergency setting, it is critical to identify the radiologic findings that represent severe ischemia, which is associated with higher morbidity, and for which surgical treatment with exploratory laparotomy and resection of the bowel is likely necessary. The presence of pneumatosis, or gas in the bowel wall, is a concerning finding that raises the possibility of transmural infarction. Locules of gas may track into mesenteric veins and the portal vein (1). A frank pneumoperitoneum indicates a bowel perforation secondary to transmural wall necrosis. Severe ischemia with transmural infarction also can be seen as mesenteric fat stranding and ascites.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ”In a hemodynamically stable patient who presents early with favorable vascular and bowel CT findings, endovascular treatment may be the best option. In a meta-analysis, Salsano et al evaluated and compared the outcomes of seven studies and showed that endovascular therapy had better outcomes, with significantly lower mortality and bowel resection.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ” Certain multidetector CT findings must be considered in planning an intervention and should be detailed in the CT interpretation. Placing a stent for proximal SMA stenosis most commonly due to calcified atherosclerotic disease is best achieved with a noncovered balloon-expandable stent as opposed to a self- expandable nitinol stent. In this scenario, the rigidity and hoop-strength of the balloon-expandable stent make it better at preventing elastic recoil from the atherosclerotic plaque. However, self-expandable stents are often placed in distal stenosis of SMA branches, because they are generally more flexible and more likely to accommodate greater vessel tortuosity.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • ” Diagnosis.—SMA dissection can be divided into two groups: spontaneous isolated and combined. Spontaneous isolated SMA dissection (SISMAD) is SMA dissection that occurs without aortic dissection . Combined SMA dissection is more common and is due to an aortic dissection flap extending into the proximal vessel. SISMAD is a rare disease, although it is being identified more often with the use of CT angiography. An increased incidence of SISMAD has been described in men and patients aged 50–70 years old. Dissection is the result of blood entering the media of an artery through an intimal defect and creating a true lumen in continuity with the unaffected aorta and a false lumen.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “SMA aneurysms account for 5.5% of all visceral artery aneurysms and are the third most common type. They occur predominantly in men and in the 5th decade of life. SMA aneurysms are associated with substantial morbidity, because they put the patient at risk for rupture and hemorrhage. Approximately 38%–50% of patients present with rupture, and mortality rates range from 40% to 60%. The majority of aneurysms occur in the proximal 5 cm of the SMA.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “There are several causes of aneurysms including atherosclerosis, trauma, surgery, inflammation and/or vasculitis, infection, and collagen vascular disorders. Most commonly, SMA aneurysms are asymptomatic and are found incidentally at imaging. Patients may present with colicky abdominal pain or rarely a pulsatile mass. Patients who present with a rupture have signs of hemodynamic compromise. SMA aneurysms must be identified and characterized by the radiologist to give the emergency medicine physician and vascular interventional radiologist the opportunity to treat appropriately.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vasculitis refers to inflammation of the blood vessel walls and includes a diverse group of conditions. Some of the vasculitides may involve the SMA. Up to 50% of cases of vasculitis involve the mesenteric arteries, but only 16% manifest as isolated mesenteric disease. The pathogenesis of vasculitis varies with each type and can include cell-mediated, immune complex–mediated, and antineutrophil cytoplasmic antibody–mediated inflammation.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Segmental arterial mediolysis is a nonatherosclerotic and noninflammatory arteriopathy characterized by lysis of the smooth muscle of the outer media that results in dissecting aneurysms and intramural hematomas. Unlike those of most vasculitides, inflammatory or immune markers are most often normal. Middle-aged and elderly patients are affected most commonly and can present with abdominal pain, distention, decreased hemoglobin level, bowel ischemia, or shock. Imaging findings of segmental arterial mediolysis are similar to those of other vasculitides, although it classically results in alternating aneurysm and stenosis of the abdominal splanchnic arteries, without involvement of other vessel.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Vasculitis refers to inflammation of the blood vessel walls and includes a diverse group of conditions. Some of the vasculitides may involve the SMA. Up to 50% of cases of vasculitis involve the mesenteric arteries, but only 16% manifest as isolated mesenteric disease. The pathogenesis of vasculitis varies with each type and can include cell-mediated, immune complex–mediated, and antineutrophil cytoplasmic antibody–mediated inflammation.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “Systemic lupus erythematosus is an autoimmune disease caused by immune complex deposition that classically affects young women. The disease process often involves the joints, kidneys, gastrointestinal tract, and skin. Lupus may affect vasculature of the entire gastrointestinal tract, but the SMA distribution is involved most commonly. Polyarteritis nodosa is a medium-vessel fibrinoid necrotizing vasculitis that occurs in middle-aged to older adults. Classically, it causes microaneurysms and erosion of the arterial wall, most commonly affecting the kidneys, gastrointestinal tract, and liver.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • Segmental arterial mediolysis is a nonatherosclerotic and noninflammatory arteriopathy characterized by lysis of the smooth muscle of the outer media that results in dissecting aneurysms and intramural hematomas. Unlike those of most vasculitides, inflammatory or immune markers are most often normal. Middle-aged and elderly patients are affected most commonly and can present with abdominal pain, distention, decreased hemoglobin level, bowel ischemia, or shock. Imaging findings of segmental arterial mediolysis are similar to those of other vasculitides, although it classically results in alternating aneurysm and stenosis of the abdominal splanchnic arteries, without involvement of other vessels.
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • “CT angiographic findings of vasculitis include circumferential arterial wall thickening, luminal narrowing, and microaneurysms. Long-segment smooth tapering without evidence of atherosclerotic disease usually is seen in vasculitis. A beaded appearance of the SMA may be seen with multiple aneurysms. The extent of the disease must be detailed, because focal disease can be managed with surgical or endovascular treatment, and diffuse disease is managed medically.”
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
  • Colonic diverticulosis and angiodysplasia can be differentiated readily at multidetector CT, which is of prognostic importance, because bleeding recurs in up to 85% of untreated patients with angiodysplasia, while only 25% of untreated diverticular patients experience recurrent bleeding.
    High-Value Multidetector CT Angiography of the Superior Mesenteric Artery: What Emergency Medicine Physicians and Interventional Radiologists Need to Know.
    Ghodasara N, Liddell R, Fishman EK, Johnson PT.
    Radiographics. 2019 Mar-Apr;39(2):559-577.
© 1999-2019 Elliot K. Fishman, MD, FACR. All rights reserved.