Everything you need to know about Computed Tomography (CT)

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February 2017 Imaging Pearls - Learning Modules | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ February 2017
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3D and Workflow

    • BACKGROUND: The interpretation of CT scans for the evaluation of calcaneal fractures is difficult. Three-dimensional (3D) reconstruction (volume rendering technique [VRT]) has been valuable in the evaluation of irregularly shaped bones. However, their value for the analysis of calcaneal fractures is still debated. Therefore, the objective of this study was to assess the effect of additional use of 3D CTs in calcaneal fractures.


      CONCLUSION: The evaluation of CT scans of calcaneal fractures was improved by the additional use of 3D images (VRT).


      Value of 3D Reconstructions of CT Scans for Calcaneal Fracture Assessment.
Roll C et al.
 Foot Ankle Int. 2016 Nov;37(11):1211-1217
    • METHODS: In a prospective multicenter study, the CT data set of 5 different fractures was presented to 57 evaluators. First, the participating surgeons were asked to assess the fractures on the basis of axial, coronal, and sagittal reconstructions using a multiple-choice questionnaire. Second, 3D reconstructions (VRT) were presented. The CT scans were validated by the intraoperative findings and the results were compared to the model solution of 3 foot and ankle surgeons. Intra- and interrater reliabilities were calculated.

      
Value of 3D Reconstructions of CT Scans for Calcaneal Fracture Assessment.
Roll C et al.
 Foot Ankle Int. 2016 Nov;37(11):1211-1217
    • “CRT, which is similar to conventional VRT, is not primarily intended for diagnostic radiologic image analysis, and therefore it should be used primarily as a tool to deliver visual information in the form of radiologic image reports. Using CRT for forensic visualization might have advantages over using VRT if conveying a high degree of visual realism is of importance. Most of the shortcomings of CRT have to do with the software being an early prototype.”

      
Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study 
Ebert LC et al.
AJR 2017; 208:233–240
    • “On the basis of most of the renderings presented, CRT appears to be equal or superior to VRT with respect to the realism and understandability of the visualized findings. Overall, in terms of realism, the difference between the techniques was statistically significant (p < 0.05). Most participants perceived the CRT renderings to be more understandable than the VRT renderings, but that difference was not statistically significant (p > 0.05).”


      Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study 
Ebert LC et al.
AJR 2017; 208:233–240
    • “With the advent of increasingly affordable and increasingly faster computers, VRTs have become the established standard for real-time 3D visualization, offering more image detail and, thus, more realism than SSD. This trend has been fueled by the ever-increasing computational power of workstations and desktop computers.”


      Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study 
Ebert LC et al.
AJR 2017; 208:233–240
    • “Depth-of-field effects display the area around a focal point as a sharp image, and the objects that are closer to or more distant from the focal point are displayed as blurred images. To further increase depth perception, shadows are calculated correct- ly. In addition, the reduction of ambient light exposure in partially occluded areas is simulated (i.e., through ambient occlusion mapping).”

      
Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study 
Ebert LC et al.
AJR 2017; 208:233–240
    • “This prototype CRT already provides some insight into what we do or do not consider to be better images. With these insights, it offers a glimpse into a future where medical image reconstruction might use certain features of photorealism that add clarity for the viewer, such as lens blur, surface appearance, 3D model lighting, and better color distinction.”

      
Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study 
Ebert LC et al.
AJR 2017; 208:233–240
    • “CRT, which is similar to conventional VRT, is not primarily intended for diagnostic radiologic image analysis and thus should be used primarily as a tool to deliver visual information in the form of radiologic image reports.”

      
Forensic 3D Visualization of CT Data Using Cinematic Volume Rendering: A Preliminary Study 
Ebert LC et al.
AJR 2017; 208:233–240
    • Since the advent of whole-body CT scanning in 1974, many studies have been made in its application to all parts of the body. One of the most fruitful areas has been CT of the spinal cord. The only limitation appears to be the technique used; there is no substitute for a good technique. We shall first review standard CT techniques, then mention special techniques for spinal cord work, and finally discuss the future.


      CT techniques.
Ledley RS
Eur Neurol. 1982;21(3):204-9.
Adrenal

    • “Imaging characteristics of adrenal tumors on CT scan predict benign pathology 100% of the time. Regardless of size, when interpreted as benign on CT scan, laparoscopic adrenalectomy, if technically feasible, should be the technique used when surgery is offered, or close surveillance may be a safe alternative.”


      Computed Tomography in the Management of Adrenal Tumors: Does Size Still Matter?
Azoury SC, Nagarajan N, Young A, Mathur A, Prescott JD, Fishman EK, Zeiger MA
J Comput Assist Tomogr. 2017 Jan 20 [Epub ahead of print]
    • METHODS: A retrospective review was conducted of patients who underwent unilateral adrenalectomy for an adrenal mass between January 2005 and July 2015. Tumors were classified as benign, indeterminate, or malignant based on preoperative CT findings.


      RESULTS: Of 697 patients who underwent unilateral adrenalectomy, 216 met the inclusion criteria. Pathology was benign in 88.4%, indeterminate in 2.3%, and malignant in 9.3%, with a median tumor diameter of 2.7 cm (interquartile range, 1.7-4.1 cm) and 9.5 cm (interquartile range, 7.1-12 cm) in the benign and malignant groups, respectively (P < 0.001). Of the tumors with benign features on CT, 100% (143/143) had benign final pathology.”


      Computed Tomography in the Management of Adrenal Tumors: Does Size Still Matter?
Azoury SC, Nagarajan N, Young A, Mathur A, Prescott JD, Fishman EK, Zeiger MA
J Comput Assist Tomogr. 2017 Jan 20 [Epub ahead of print]
    • OBJECTIVES: To compare robot-assisted laparoscopic adrenalectomy (RALA) and open adrenalectomy (OA) with regard to intra-operative complications, peri-operative outcome and cost effectiveness.
      
CONCLUSIONS: The study showed that RALA was safe and cost-effective compared with OA. Increasing experience leads to similar operating times, putting high-volume centres at an advantage.
Robot-assisted vs open adrenalectomy: evaluation of cost-effectiveness and peri-operative outcome.


      Probst KA et al.
BJU Int. 2016 Dec;118(6):952-957
    • RESULTS: As a result of the matching process, patient groups did not differ in their main characteristics. Length of hospital stay was shorter for RALA than for OA (11.1 ± 4.8 vs 6.8 ± 1.2 days; P < 0.01) as was IMC treatment (2.3 ± 1.7 vs 1.2 ± 0.4 days; P < 0.01). The mean operating time was longer for RALA (128.5 ± 46.5 vs 102.2 ± 44.5 min; P = 0.03), but the last 10 RALA procedures (mean: 97.1 ± 35.2 min) were similar to OA. The rate of complications was similar in the two groups. Estimated costs were €8 627.5 for OA and €7 334 for RALA.
Robot-assisted vs open adrenalectomy: evaluation of cost-effectiveness and peri-operative outcome.


      Probst KA et al.
BJU Int. 2016 Dec;118(6):952-957
    • PURPOSE: To evaluate the surgical feasibility of retroperitoneal laparoscopic adrenalectomy for tumors exceeding 5 cm.
      RESULTS: The estimated blood loss (271.75 ± 232.98 mL vs. 367.24 ± 275.11 mL; p = 0.037), time to ambulation (1.60 ± 0.49 days vs. 1.89 ± 0.31 days; p = 0.001), and postoperative hospitalization (7.88 ± 3.08 days vs. 9.264 ± 3.10 days; p = 0.012) were significantly higher in group II. The operation time and hemoglobin level change were not statistically different between groups. Blood transfusions were performed in 3 patients from group I and 6 patients from group II (5.3 vs. 7.9 %; p = 0.449). No patients experienced conversion to open surgery.

      CONCLUSIONS: Retroperitoneal laparoscopic adrenalectomy can be used in patients with tumors larger than 5 cm.
Is larger tumor size a contraindication to retroperitoneal laparoscopic adrenalectomy?

      
Hwang I et al.
World J Urol. 2014 Jun;32(3):723-8
Kidney

    • Renal Vein Thrombosis: Etiologies
      - Renal cell carcinoma
      - Transitional cell carcinoma
      - Extra-renal tumors including adrenal cancer
      - Leiomyosarcoma of the renal vein (primary)
      - trauma
    • “In contradistinction to atherosclerotic stenosis, which are seen in the proximal renal artery, FMD-related stenosis tend to occur in the middle to distal portion of the renal artery.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “RAAs 1.0–1.5 cm in diameter should be evaluated with surveillance imaging every 1–2 years. Patients with RAAs larger than 1.5 cm should be referred for definitive treatment. Additional indications for treatment of RAAs include uncontrolled hypertension and symptomatic cases due to peripheral vascular bed embolism.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The main renal artery normally arises from the abdominal aorta, below the level of the superior mesenteric artery at the L2 vertebral body level. The main renal artery is typically 4–6 cm in length and 5–6 mm in diameter. The right main renal artery is longer and often originates slightly superior to the left renal artery. The right renal artery is the only major vessel to course posterior to the inferior vena cava (IVC).”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “In contrast to accessory renal arteries, which enter the kidney through the hilum, aberrant renal arteries, also known as polar arteries, enter the kidney through the capsule outside the hilum.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “ Prehilar branches of the main renal artery that arise less than 1.5–2.0 cm from the origin should be noted in patients who are being evaluated as possible renal donors, because these early branches may complicate the surgical arterial anastomosis.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The main renal vein usually lies anterior
to the renal artery at the renal hilum. The left renal vein has an average length of 6–10 cm and normally courses anteriorly between the superior mesenteric artery and aorta before emptying into the medial aspect of the IVC. The right renal vein has an average length of 2–4 cm and joins the lateral aspect of the IVC.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “RAS is the most common cause of secondary hy- pertension and is found in 1%–5% of all patients 
who have hypertension. In greater than two- thirds of cases of RAS, focal narrowing of the renal artery lumen is caused by atherosclerosis. The majority of affected individuals are male and older than 50 years. Atherosclerotic renovascular disease correlates with overall atherosclerotic burden, and the prevalence of this condition is higher among patients with known coronary artery disease.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “RAS leads to reduced perfusion to the kidney, which then results in systemic hypertension due 
to activation of the renin-angiotensin system . RAS is also an important factor of end-stage renal disease, particularly in persons older than 50 years . RAS caused by atherosclerosis typically occurs at the origin of the renal artery or within the proximal 2 cm of the renal artery. When stenosis 
is detected, careful inspection of the contralateral renal artery is important, as bilateral lesions occur in 30% of cases.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Fibromuscular dysplasia (FMD) is a nonath- erosclerotic noninflammatory vascular disease of medium-sized and large arteries that results in focal areas of irregular wall thickening . FMD is the second most common cause of RAS and is found in younger patients, with 
a female-to-male ratio of 9:1. The most commonly affected vessel is the renal artery (in 75% of cases) followed by the internal carotid artery.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “FMD results in stenosis, aneurysm, dissection, and occlusion of the involved vessels. FMD is subclassi ed into three categories based on the involved arterial layer: medial fibroplasia, which accounts for 80%–90% of cases; intimal fibroplasia, which accounts for 10% of cases; and adventitial fibroplasia, which has an unknown frequency.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “In contradistinction to atherosclerotic stenosis, which are seen in the proximal renal artery, 
FMD-related stenosis tend to occur in the middle to distal portion of the renal artery. When FMD is discovered in a renal artery, close inspection of the contralateral renal artery is prudent, because FMD occurs bilaterally in two- thirds of patients. Up to 10% of all cases of FMD have associated renal artery aneurysms (RAAs) .”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The most common subtype, medial fibrobroplasia, is characterized by alternating segments of stenosis and dilatation, which create the “string of pearls” appearance . The intimal medial fibroplasia subtype is characterized by focal long- segment tubular areas of luminal stenosis. CT angiography has been shown to be 100% sensitive for the diagnosis of FMD, and MR angiography is reported to have a sensitivity of 97% and a specificity of 93% for this diagnosis.” 


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “However, spontaneous renal artery dissection is a rare entity that occurs without
a known inciting event. Predisposing factors include FMD, malignancy-related hypertension, severe atherosclerosis, Marfan syndrome, Ehlers- Danlos syndrome, subadventitial angioma, cystic medial necrosis, cocaine abuse, and extreme physical exertion.”
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Aneurysms of the renal artery are true aneurysms caused by degeneration and weakening of the elastic fibers of the arterial wall, with subsequent expansion caused by high intraluminal pressure. The estimated prevalence of RAAs is approximately 0.1%; most of them are detected incidentally in asymptomatic patients. However, patients may present with findings of rupture, thrombosis, or embolism.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The management of RAAs is based in part on the size of the aneurysm and the clinical setting; however, size does not have a direct correlation with rupture. RAAs 1.0–1.5 cm in diameter should be evaluated with surveillance imaging every 1–2 years. Patients with RAAs larger than 1.5 cm should be referred for definitive treatment . Additional indications for treatment of RAAs include uncontrolled hypertension and symptomatic cases due to peripheral vascular bed embolism. Pregnant women also are at high risk for RAA rupture.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Pseudoaneurysms of the renal artery occur as a result of direct injury to the arterial wall with subsequent disruption and extravasation of the blood contained in the arterial adventitia or surrounding tissues . Pseudoaneurysms occur most often in response to iatrogenic or penetrating trauma . Multiple intraparenchymal pseudoaneurysms can develop with vasculitis and as a result of amphetamine use. A pseudoaneurysm rupture may manifest as hematuria, and pain, and/or hypotensive shock.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Vascular abnormalities are found in 0.4%–6.4% of patients with NF-1, and the renal artery is the most commonly involved artery, being affected in 41% of patients with associated vascular abnormalities. Unlike atherosclerotic stenosis, NF-1–associated stenosis often occur in patients younger than 50 years, spare the renal artery origin, are long and tapered, and extend into segmental and intrarenal branches. The stenosis involved with NF-1 are bilateral in 32% of patients. Less commonly, NF-1 manifests with RAAs.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Renal arteriovenous malformations (AVMs) are developmental anomalies in which an abnormal connection is present between a renal artery and renal vein owing to a nidus consisting of a network of abnormal vessels. Renal AVMs are usually symp- tomatic; gross hematuria results from the rupture of small venules into calyces that is caused by abnormally increased intravascular pressure. Other symptoms include renovascular hypertension, high-output cardiac failure, and flank pain.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “An arteriovenous fistula (AVF) is an abnormal direct connection of an artery to a vein without an intervening capillary bed. Most renal AVFs are acquired, and they usually have an iatrogenic cause such as percutaneous nephrostomy or result from penetrating trauma. In up to 18% of cases, AVFs occur after renal biopsy. Idiopathic cases are postulated to occur when an RAA ruptures into an adjacent vein. Most patients are asymptomatic, although they may present with hematuria and flank pain.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The nutcracker phenomenon occurs when the left renal vein is compressed between the aorta and superior mesenteric artery and consequently results in left renal vein hypertension. The term nutcracker syndrome refers to the clinical signs and symptoms that can result from this anatomic finding.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Nutcracker syndrome is commonly found in thin young females. A history of recent substantial weight loss also is implicated in cases of nutcracker syndrome. Hematuria and and pain are common clinical symptoms. Additional symptoms related to pelvic congestion syndrome also may be present. Compression of the left renal vein can cause left renal vein–to–gonadal vein reflux that results in lower limb varices and varicoceles in males.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Thrombosis that leads to narrowing or occlu- sion of the renal vein can be caused by a bland or tumor thrombus. Patients present with gross hematuria, flank pain, and signs of renal failure. Risk factors of bland renal vein thrombosis include glomerulonephritis, collagen vascular disease, diabetes, and trauma.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • OBJECTIVE. The objective of our study was to determine the sensitivity of thin axial and coronal maximum-intensity-projection (MIP) images for the detection of renal stones on contrast-enhanced CT performed in the portal venous phase. 

      CONCLUSION. Thin axial images are highly sensitive for the detection of renal stones ≥ 2 mm on portal venous phase CT. Coronal MIP images do not improve renal stone detection over thin axial images. 


      Detection of Renal Stones on Portal Venous Phase CT: Comparison of Thin Axial and Coronal Maximum- Intensity-Projection Images 
Corwin MT et al.
AJR 2016; 207:1200–1204
    • “The results of our study show that thin images on portal venous phase CECT have a high sensitivity for the detection of renal stones ≥ 2 mm. Unenhanced CT is the recommended imaging test for patients pre- senting with acute flank pain and suspicion of renal stone disease . CECT has traditionally been thought to be limited in detecting renal stones and has not been recommended in this setting. In fact, the American College of Radiology appropriateness criteria give CT of the abdomen and pelvis with contrast material the lowest rating level (2, usually not appropriate) in this situation.”

      
Detection of Renal Stones on Portal Venous Phase CT: Comparison of Thin Axial and Coronal Maximum- Intensity-Projection Images 
Corwin MT et al.
AJR 2016; 207:1200–1204
    • “In our practice, we routinely evaluate thin axial reconstructed images or coronal MIP images to optimize renal stone detection on unenhanced CT. The results of our study show that thin axial images improve the sensitivity of stone detection during portal venous phase CECT to 83.1–89.9% for all stones.”


      Detection of Renal Stones on Portal Venous Phase CT: Comparison of Thin Axial and Coronal Maximum- Intensity-Projection Images 
Corwin MT et al.
AJR 2016; 207:1200–1204
    • “Therefore, we conclude that thin axial images during portal venous phase CECT depict renal stones ≥ 2 mm with high sensitivity. If CECT is performed when there is some concern for renal stones, review of thin images should be performed to optimize stone detection.”


      Detection of Renal Stones on Portal Venous Phase CT: Comparison of Thin Axial and Coronal Maximum- Intensity-Projection Images 
Corwin MT et al.
AJR 2016; 207:1200–1204
Musculoskeletal

    • “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 interprets the examination may have a direct impact on radiological diagnosis, subsequent choice of treatment, and clinical outcome.”

      
Variability in diagnostic error rates of 10 MRI centers performing lumbar spine MRI examinations on the same patient within a 3-week period
Herzog R et al.
The Spine Journal (in press)
    • Methods: Interpretive findings from 10 study MRI examinations were tabulated and compared for variability and errors. Two of the authors, both subspecialist spine radiologists from different institutions, independently reviewed the reference examinations and then came to a final diagnosis by consensus. Errors of interpretation in the study examinations were considered present if a finding present or not present in the study examination's report was not present in the reference examinations.


      Variability in diagnostic error rates of 10 MRI centers performing lumbar spine MRI examinations on the same patient within a 3-week period
Herzog R et al.
The Spine Journal (in press)
    • “BACKGROUND CONTEXT: In today’s health-care climate, magnetic resonance imaging (MRI) is often perceived as a commodity—a service where there are no meaningful differences in quality and thus an area in which patients can be advised to select a provider based on price and convenience alone. If this prevailing view is correct, then a patient should expect to receive the same radiological diagnosis regardless of which imaging center he or she visits, or which radiologist reviews the examination. Based on their extensive clinical experience, the authors believe that this assumption is not correct and that it can negatively impact patient care, outcomes, and costs.”

      
Variability in diagnostic error rates of 10 MRI centers performing lumbar spine MRI examinations on the same patient within a 3-week period
Herzog R et al.
The Spine Journal (in press)
    • “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. A global Fleiss kappa statistic, computed across all reported findings, was 0.20±0.06, indicating poor overall agreement on interpretive findings. The average interpretive error count in the study examinations was 12.5±3.2 (both false-positives and false-negatives). The average false-negative count per examination was 10.9±2.9 out of 25 and the average false-positive count was 1.6±0.9, which correspond to an average true-positive rate (sensitivity) of 56.4%±11.7 and miss rate of 43.6%±11.7.”


      Variability in diagnostic error rates of 10 MRI centers performing lumbar spine MRI examinations on the same patient within a 3-week period
Herzog R et al.
The Spine Journal (in press)
    • “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. A global Fleiss kappa statistic, computed across all reported findings, was 0.20±0.06, indicating poor overall agreement on interpretive findings.”


      Variability in diagnostic error rates of 10 MRI centers performing lumbar spine MRI examinations on the same patient within a 3-week period
Herzog R et al.
The Spine Journal (in press)
    • “Ultimately, it is the authors' opinions that accurate and complete diagnostic information at the onset of an injury or illness is critical to improve the chances for a patient's full recovery. However, reducing diagnostic errors and variability in reported findings will require the development and adoption of systematic mechanisms for measuring diagnostic MRI quality, including error rates. The authors acknowledge that accurately measuring interpretive errors at scale is a significant challenge and that some health-care providers may be reluctant to adopt such a system due to concerns around exposure of their errors, negative impact on reimbursement, and potential liability.”


      Variability in diagnostic error rates of 10 MRI centers performing lumbar spine MRI examinations on the same patient within a 3-week period
Herzog R et al.
The Spine Journal (in press)
    • BACKGROUND: The interpretation of CT scans for the evaluation of calcaneal fractures is difficult. Three-dimensional (3D) reconstruction (volume rendering technique [VRT]) has been valuable in the evaluation of irregularly shaped bones. However, their value for the analysis of calcaneal fractures is still debated. Therefore, the objective of this study was to assess the effect of additional use of 3D CTs in calcaneal fractures.

      CONCLUSION: The evaluation of CT scans of calcaneal fractures was improved by the additional use of 3D images (VRT).


      Value of 3D Reconstructions of CT Scans for Calcaneal Fracture Assessment. Roll C et al.
 Foot Ankle Int. 2016 Nov;37(11):1211-1217
    • METHODS: In a prospective multicenter study, the CT data set of 5 different fractures was presented to 57 evaluators. First, the participating surgeons were asked to assess the fractures on the basis of axial, coronal, and sagittal reconstructions using a multiple-choice questionnaire. Second, 3D reconstructions (VRT) were presented. The CT scans were validated by the intraoperative findings and the results were compared to the model solution of 3 foot and ankle surgeons. Intra- and interrater reliabilities were calculated.


      Value of 3D Reconstructions of CT Scans for Calcaneal Fracture Assessment.
Roll C et al.
 Foot Ankle Int. 2016 Nov;37(11):1211-1217
Pancreas

    • “Stage III borderline resectable tumor is characterized by a localized tumor abutting a major artery, including the celiac artery, common hepatic artery, or SMA. With regard to the portovenous axis, any degree of involvement falls into the category of borderline resectable disease as long as the vein can be technically resected and reconstructed.”


      Tumor-Vessel Relationships in Pancreatic Ductal Adenocarcinoma at Multidetector CT: Different Classification Systems and Their Influence on Treatment Planning 
Zaky AM, Wolfgang CL, Weiss MJ, Javed AA, Fishman EK, 
Zaheer A 
RadioGraphics 2017; 37:93–112
    • “The wall of the artery is thicker than that of the vein, and the flow rate in the artery is higher than that in the vein, so any change in the caliber of the artery or the presence of throm- bus in the artery carries a higher risk of invasion than those findings in the vein.”


      Tumor-Vessel Relationships in Pancreatic Ductal Adenocarcinoma at Multidetector CT: Different Classification Systems and Their Influence on Treatment Planning 
Zaky AM, Wolfgang CL, Weiss MJ, Javed AA, Fishman EK, 
Zaheer A 
RadioGraphics 2017; 37:93–112
    • “The change of the normal shape of the portal vein or SMV to a teardrop shape on axial multidetector CT images that is caused by tumor encasement or by tethering by adjacent fibrosis is referred to as the “teardrop sign” and is highly associated with vascular invasion.”

      
Tumor-Vessel Relationships in Pancreatic Ductal Adenocarcinoma at Multidetector CT: Different Classification Systems and Their Influence on Treatment Planning 
Zaky AM, Wolfgang CL, Weiss MJ, Javed AA, Fishman EK, 
Zaheer A 
RadioGraphics 2017; 37:93–112
    • “The change of the normal shape of the portal vein or SMV to a teardrop shape on axial multidetector CT images that is caused by tumor encasement or by tethering by adjacent fibrosis is referred to as the “teardrop sign” and is highly associated with vascular invasion. At preoperative multidetector CT, the probability of vascular invasion is up to 40% for tumor abutment ( ≤180° contact), compared with 80% in the presence of tumor encasement (>180° contact), and 100% if the tumor is completely surrounding the portal vein or SMV.”


      Tumor-Vessel Relationships in Pancreatic Ductal Adenocarcinoma at Multidetector CT: Different Classification Systems and Their Influence on Treatment Planning 
Zaky AM, Wolfgang CL, Weiss MJ, Javed AA, Fishman EK, 
Zaheer A 
RadioGraphics 2017; 37:93–112
    • “A replaced
right hepatic artery is the most common hepatic arterial anatomic variant. The rate of occurrence of this variant, in which the proper hepatic artery gives off only the left hepatic artery while the right hepatic artery originates from the SMA to pass posterolateral to the portal vein, has been reported in the literature to range from 11% to 21%.”


      Tumor-Vessel Relationships in Pancreatic Ductal Adenocarcinoma at Multidetector CT: Different Classification Systems and Their Influence on Treatment Planning 
Zaky AM, Wolfgang CL, Weiss MJ, Javed AA, Fishman EK, 
Zaheer A 
RadioGraphics 2017; 37:93–112
Practice Management

    • “At Saxbys, we recognized that the best team members for our business have the same three personal traits: they’re outgoing, detail oriented, and disciplined. Or, as we say, they’re “O.D.D.” Regard- less of their prior work experience, they must possess these three traits.”


      The Culture of Hospitality 
Nick Bayer, Elliot K. Fishman, Karen M. Horton, Pamela T. Johnson
JACR (in press) DOI: http://dx.doi.org/10.1016/j.jacr.2016.10.007
    • “We hire engaging people who embrace the importance of a positive human experience and accordingly believe in the business model with passion. As a result, our team members love the company and want to contribute to its overall quality.”


      The Culture of Hospitality 
Nick Bayer, Elliot K. Fishman, Karen M. Horton, Pamela T. Johnson
JACR (in press) DOI: http://dx.doi.org/10.1016/j.jacr.2016.10.007
    • Golden Rule: “Treat others the way you want to be treated.” 

      Platinum Rule: “Treat others the way they want to be treated.” 

      Double Platinum Rule: “Treat others the way they don’t even know they want to be treated.” 


      The Culture of Hospitality 
Nick Bayer, Elliot K. Fishman, Karen M. Horton, Pamela T. Johnson
JACR (in press) DOI: http://dx.doi.org/10.1016/j.jacr.2016.10.007
    • “Radiology departments need to be 
proactive to facilitate a positive experience for the patient. Patients who are referred to radiology begin their experience when they call to schedule the examination and complete the experi- ence when their physician explains the results of the test.” 


      The Culture of Hospitality 
Nick Bayer, Elliot K. Fishman, Karen M. Horton, Pamela T. Johnson
JACR (in press) DOI: http://dx.doi.org/10.1016/j.jacr.2016.10.007
    • “Careful selection of receptionists, radiology nurses, and technologists with these three skills is essential to running a department that provides a positive experience for a patient. Because of the intrinsic unpleasantries of any medical procedure, our staff needs to go above and beyond and embrace the Double Platinum Rule: “Treat others the way they don’t even know they want to be treated.” Anticipate patients’ needs and exceed their expectations.”

      
The Culture of Hospitality 
Nick Bayer, Elliot K. Fishman, Karen M. Horton, Pamela T. Johnson
JACR (in press) DOI: http://dx.doi.org/10.1016/j.jacr.2016.10.007
    • “Radiology residencies need to select medical students who are outgoing, detail-oriented, and disciplined and instill in trainees the importance of excellent customer service for their patients and ordering providers. Radiologists who welcome interaction, who are receptive to consultations, and who generate interpretations that effectively and efficiently guide patient management provide a positive experience for the referring providers. This is the business model that will ensure practice longevity as we transition to a value-based health care system.” 


      The Culture of Hospitality 
Nick Bayer, Elliot K. Fishman, Karen M. Horton, Pamela T. Johnson
JACR (in press) DOI: http://dx.doi.org/10.1016/j.jacr.2016.10.007
Vascular

    • “In contradistinction to atherosclerotic stenosis, which are seen in the proximal renal artery, FMD-related stenosis tend to occur in the middle to distal portion of the renal artery.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “RAAs 1.0–1.5 cm in diameter should be evaluated with surveillance imaging every 1–2 years. Patients with RAAs larger than 1.5 cm should be referred for definitive treatment. Additional indications for treatment of RAAs include uncontrolled hypertension and symptomatic cases due to peripheral vascular bed embolism.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The main renal artery normally arises from the abdominal aorta, below the level of the superior mesenteric artery at the L2 vertebral body level.The main renal artery is typically 4–6 cm in length and 5–6 mm in diameter.The right main renal artery is longer and often originates slightly superior to the left renal artery. The right renal artery is the only major vessel to course posterior to the inferior vena cava (IVC).”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “In contrast to accessory renal arteries, which enter the kidney through the hilum, aberrant renal arteries, also known as polar arteries, enter the kidney through the capsule outside the hilum.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “ Prehilar branches of the main renal artery that arise less than 1.5–2.0 cm from the origin should be noted in patients who are being evaluated as possible renal donors, because these early branches may complicate the surgical arterial anastomosis.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The main renal vein usually lies anterior
to the renal artery at the renal hilum.The left renal vein has an average length of 6–10 cm and normally courses anteriorly between the superior mesenteric artery and aorta before emptying into the medial aspect of the IVC. The right renal vein has an average length of 2–4 cm and joins the lateral aspect of the IVC.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “RAS is the most common cause of secondary hy- pertension and is found in 1%–5% of all patients 
who have hypertension. In greater than two- thirds of cases of RAS, focal narrowing of the renal artery lumen is caused by atherosclerosis. The majority of affected individuals are male and older than 50 years. Atherosclerotic renovascular disease correlates with overall atherosclerotic burden, and the prevalence of this condition is higher among patients with known coronary artery disease.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “RAS leads to reduced perfusion to the kidney, which then results in systemic hypertension due 
to activation of the renin-angiotensin system . RAS is also an important factor of end-stage renal disease, particularly in persons older than 50 years . RAS caused by atherosclerosis typically occurs at the origin of the renal artery or within the proximal 2 cm of the renal artery. When stenosis 
is detected, careful inspection of the contralateral renal artery is important, as bilateral lesions occur in 30% of cases.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Fibromuscular dysplasia (FMD) is a nonath- erosclerotic noninflammatory vascular disease of medium-sized and large arteries that results in focal areas of irregular wall thickening . FMD is the second most common cause of RAS and is found in younger patients, with 
a female-to-male ratio of 9:1. The most commonly affected vessel is the renal artery (in 75% of cases) followed by the internal carotid artery.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “FMD results in stenosis, aneurysm, dissection, and occlusion of the involved vessels. FMD is subclassi ed into three categories based on the involved arterial layer: medial fibroplasia, which accounts for 80%–90% of cases; intimal fibroplasia, which accounts for 10% of cases; and adventitial fibroplasia, which has an unknown frequency.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “In contradistinction to atherosclerotic stenosis, which are seen in the proximal renal artery, 
FMD-related stenosis tend to occur in the middle to distal portion of the renal artery. When FMD is discovered in a renal artery, close inspection of the contralateral renal artery is prudent, because FMD occurs bilaterally in two- thirds of patients. Up to 10% of all cases of FMD have associated renal artery aneurysms (RAAs) .”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The most common subtype, medial fibrobroplasia, is characterized by alternating segments of stenosis and dilatation, which create the “string of pearls” appearance . The intimal medial fibroplasia subtype is characterized by focal long- segment tubular areas of luminal stenosis. CT angiography has been shown to be 100% sensitive for the diagnosis of FMD, and MR angiography is reported to have a sensitivity of 97% and a specificity of 93% for this diagnosis.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “However, spontaneous renal artery dissection is a rare entity that occurs without
a known inciting event. Predisposing factors include FMD, malignancy-related hypertension, severe atherosclerosis, Marfan syndrome, Ehlers- Danlos syndrome, subadventitial angioma, cystic medial necrosis, cocaine abuse, and extreme physical exertion.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Aneurysms of the renal artery are true aneurysms caused by degeneration and weakening of the elastic fibers of the arterial wall, with subsequent expansion caused by high intraluminal pressure. The estimated prevalence of RAAs is approximately 0.1%; most of them are detected incidentally in asymptomatic patients. However, patients may present with findings of rupture, thrombosis, or embolism.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The management of RAAs is based in part on the size of the aneurysm and the clinical setting; however, size does not have a direct correlation with rupture. RAAs 1.0–1.5 cm in diameter should be evaluated with surveillance imaging every 1–2 years. Patients with RAAs larger than 1.5 cm should be referred for definitive treatment . Additional indications for treatment of RAAs include uncontrolled hypertension and symptomatic cases due to peripheral vascular bed embolism. Pregnant women also are at high risk for RAA rupture.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Pseudoaneurysms of the renal artery occur as a result of direct injury to the arterial wall with subsequent disruption and extravasation of the blood contained in the arterial adventitia or surrounding tissues . Pseudoaneurysms occur most often in response to iatrogenic or penetrating trauma . Multiple intraparenchymal pseudoaneurysms can develop with vasculitis and as a result of amphetamine use. A pseudoaneurysm rupture may manifest as hematuria, and pain, and/or hypotensive shock.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Vascular abnormalities are found in 0.4%–6.4% of patients with NF-1, and the renal artery is the most commonly involved artery, being affected in 41% of patients with associated vascular abnormalities. Unlike atherosclerotic stenosis, NF-1–associated stenosis often occur in patients younger than 50 years, spare the renal artery origin, are long and tapered, and extend into segmental and intrarenal branches. The stenosis involved with NF-1 are bilateral in 32% of patients. Less commonly, NF-1 manifests with RAAs.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Renal arteriovenous malformations (AVMs) are developmental anomalies in which an abnormal connection is present between a renal artery and renal vein owing to a nidus consisting of a network of abnormal vessels. Renal AVMs are usually symp- tomatic; gross hematuria results from the rupture of small venules into calyces that is caused by abnormally increased intravascular pressure. Other symptoms include renovascular hypertension, high-output cardiac failure, and flank pain.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “An arteriovenous fistula (AVF) is an abnormal direct connection of an artery to a vein without an intervening capillary bed. Most renal AVFs are acquired, and they usually have an iatrogenic cause such as percutaneous nephrostomy or result from penetrating trauma. In up to 18% of cases, AVFs occur after renal biopsy. Idiopathic cases are postulated to occur when an RAA ruptures into an adjacent vein. Most patients are asymptomatic, although they may present with hematuria and flank pain.”
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “The nutcracker phenomenon occurs when the left renal vein is compressed between the aorta and superior mesenteric artery and consequently results in left renal vein hypertension. The term nutcracker syndrome refers to the clinical signs and symptoms that can result from this anatomic finding.”

      
Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Nutcracker syndrome is commonly found in thin young females. A history of recent substantial weight loss also is implicated in cases of nutcracker syndrome. Hematuria and and pain are common clinical symptoms. Additional symptoms related to pelvic congestion syndrome also may be present. Compression of the left renal vein can cause left renal vein–to–gonadal vein reflux that results in lower limb varices and varicoceles in males.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
    • “Thrombosis that leads to narrowing or occlu- sion of the renal vein can be caused by a bland or tumor thrombus. Patients present with gross hematuria, flank pain, and signs of renal failure. Risk factors of bland renal vein thrombosis include glomerulonephritis, collagen vascular disease, diabetes, and trauma.”


      Radiologic Assessment of Native Renal Vasculature: A Multimodality Review 
Sayf Al-Katib et al.
RadioGraphics 2017; 37:136–156
All images on this site are © 2017 Elliot K. Fishman, MD.