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

Colon: Appendix and Appendicitis Imaging Pearls - Educational Tools | CT Scanning | CT Imaging | CT Scan Protocols - CTisus
Imaging Pearls ❯ Colon ❯ Appendix and Appendicitis

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  • “PMP is a clinical syndrome defined as intraperitoneal accumulation of mucus due to mucinous neoplasia and is characterised by redistribution phenomenon. It includes mucinous ascites, peritoneal implants, omental caking and ovarian involvement. PMP can occur in both low- and high-grade lesions and may be due to spontaneous or iatrogenic perforation of the appendix. It most commonly arises from appendiceal neoplasms, but other associated conditions include ovarian, colon, rectum, stomach, pancreas and urachal tumours. Imaging findings are related to foreign body peritonitis with fibrotic response caused by spillage of mucus into the peritoneum.”
    Spectrum of computed tomography manifestations of appendiceal neoplasms: acute appendicitis and beyond. 
    Karande GY et al.
    Singapore Med J. 2019;60(4):173‐182. doi:10.11622/smedj.2019035
  • “The diagnostic sign on CT is low-attenuation ascites with visceral scalloping due to implants. Implants are seen on serosal surfaces and nidi in cavities reached by the usual routes of intraperitoneal flow dynamics, and they may show rim-like calcification. Frequent sites of implants are the pelvis, paracolic gutters, omentum and liver capsule. Adhesions and intestinal obstruction are the most frequent complications. In cases of concomitant mucinous tumours of the appendix and ovaries, there is often controversy about the origin of the tumour cells. However, recent evidence points to a likely appendiceal origin with secondary involvement of the peritoneum and ovaries.”
    Spectrum of computed tomography manifestations of appendiceal neoplasms: acute appendicitis and beyond. 
    Karande GY et al.
    Singapore Med J. 2019;60(4):173‐182. doi:10.11622/smedj.2019035
  • Purpose To determine the diagnostic accuracy of focused appendiceal CT as a feasible alternative to the standard CT of the abdomen and pelvis (CT-AP) in patients with suspected acute appendicitis.
    Methods Retrospective review of 200 adults with suspected acute appendicitis between January and October 2016 were included in this study. Each patient underwent CT-AP with oral and intravenous (IV) contrast. A subset of axial images start- ing at the top of L4 vertebral body to the roof of the acetabula were obtained from each study which served as the focused appendiceal CT. After review of the focused CTs, the non-focused CT-AP scans were reviewed, each patient acting as their own control. Images were assessed for ability to identify the appendix, assess for appendicitis, or identify alternative diag- noses that could account for the presenting symptoms.
  • Results Of 200 cases, the appendix was visualized in the focused CT in 191 patients. In nine studies, the appendix was not visualized in focused or standard CT-AP. Using focused CT, 42 cases were positive for acute appendicitis. This result was identical when reviewing standard CT-AP. Alternative diagnoses were present in 38 patients. Using focused CT, 14 of these were not fully covered but the readers were able to make the diagnoses confidently on the focused CTs. Only one patient had acute non-appendiceal pathology mostly outside of the field of view.
    Conclusions Focused appendiceal CT with IV and oral contrast in the setting of clinically suspected appendicitis is a suit- able alternative to conventional CT-AP.
    Focused CT for the evaluation of suspected appendicitis
    Massimo Tarulli · Joao Rezende‐Neto · Paraskevi A. Vlachou
    Abdominal Radiology (2019) 44:2081–2088
  • "Our study showed that focussed CT starting at the top of L4 vertebral body to the level of the roof of the acetabula has a high diagnostic accuracy for acute appendicitis with sensitivity and specificity of 100%. Comparing the gold standard CT-AP with focused appendiceal CT, there was no difference in the ability to visualize the appendix. Using focused CT technique, there were no cases where the appendix was completely outside the margins of the scans and only three cases where part of the appendix was not included, by a few millimetres.”
    Focused CT for the evaluation of suspected appendicitis
    Massimo Tarulli · Joao Rezende‐Neto · Paraskevi A. Vlachou
    Abdominal Radiology (2019) 44:2081–2088
  • "In conclusion, accurate diagnosis of acute appendicitis is possible with focused appendiceal CT of the abdomen and pelvis with IV and oral contrast, specifically limited to the area between the top of L4 vertebral body and the roof of the acetabulum, which is the most limited scanning field of view in studies of this kind. Moreover, this strategy ensures adequate visualization of other pathologies that mimic acute appendicitis. This presents a possibility to decrease radiation exposure to the patient, decrease in CT reading time, and decrease cost, without compromising accuracy.”
    Focused CT for the evaluation of suspected appendicitis
    Massimo Tarulli · Joao Rezende‐Neto · Paraskevi A. Vlachou
    Abdominal Radiology (2019) 44:2081–2088
  • Purpose: The study sought to compare radiologist’s ability to 1) visualize the appendix; 2) diagnose acute appendicitis; and 3) diagnose alternative pathologies responsible for acute abdominal pain among adult patients undergoing computed tomography (CT) scan with 3 different protocols: 1) intravenous (IV) contrast only; 2) IV and oral contrast with 1-hour transit time; and 3) IV and oral contrast with 3-hour transit time.
    Conclusions: Our findings suggest that reader confidence in visualizing the appendix improved with addition of oral contrast as compared to IV contrast alone. One- and 3-hour oral regimens have a similar diagnostic performance in diagnosing appendicitis.
    Intravenous and Oral Contrast vs Intravenous Contrast Alone Computed Tomography for the Visualization of Appendix and Diagnosis of Appendicitis in Adult Emergency Department Patients
    Wadhwani A et al.
    Canadian Association of Radiologists Journal, 67(3), 234–241.
  • Results: Frequency of visualizing the appendix within IV group alone was 87.3%, IV with oral for 1 hour was 94.1%, and IV with oral for 3 hours was 93.8%. Both oral contrast groups had 100% sensitivity and negative predictive value in diagnosis of acute appendicitis. Specificity for the 1- and 3-hour oral contrast groups was 94.1% and 96.1%, respectively and positive predictive value for both groups was 92%.
    Intravenous and Oral Contrast vs Intravenous Contrast Alone Computed Tomography for the Visualization of Appendix and Diagnosis of Appendicitis in Adult Emergency Department Patients
    Wadhwani A et al.
    Canadian Association of Radiologists Journal, 67(3), 234–241.
  • “Other institutions have suggested that using oral contrast can lead to increased hospital stays. Given the significant economic cost associated with prolonged ED stays, we modified our previous 3-hour protocol to the current 1-hour oral contrast protocol. However, this change did not impact the diagnostic performance as our study shows that sensitivity and NPV in ruling out appendicitis was found to be 100% for IVO1 and IVO3 groups, and the specificity and PPV for both groups was 97.7% and 96.7%, respectively.”
    Intravenous and Oral Contrast vs Intravenous Contrast Alone Computed Tomography for the Visualization of Appendix and Diagnosis of Appendicitis in Adult Emergency Department Patients
    Wadhwani A et al.
    Canadian Association of Radiologists Journal, 67(3), 234–241.
  • “In conclusion, we believe that cross-sectional imaging aids clinicians in determining the underlying cause of acute abdomen and helps guide the appropriate management. While changing our protocol from 3- to 1-hour oral consumption has not impacted the radiological interpretation or the clinical outcomes, a prospective randomized control trial will be required to estimate the effect of IV contrast alone on radiological interpretation and clinical outcomes while evaluating the underlying cause of the patient’s acute abdomen.”
    Intravenous and Oral Contrast vs Intravenous Contrast Alone Computed Tomography for the Visualization of Appendix and Diagnosis of Appendicitis in Adult Emergency Department Patients
    Wadhwani A et al.
    Canadian Association of Radiologists Journal, 67(3), 234–241.
  • “Sixteen-section multi-detector row CT transverse and coronal reformations are equally sensitive and specific for diagnosis of appendicitis. Coronal reformations improve confidence in visualization of appendix (whether diseased or normal) and in diagnosis or exclusion of appendicitis.”
    Acute appendicitis: added diagnostic value of coronal reformations from isotropic voxels at multi-detector row CT.
    Paulson EK et al.
    Radiology. 2005 Jun;235(3):879-85.
  • “Mean sensitivity and specificity for all three readers together were 96% and 95% for transverse reformations alone and 95% and 94% for combined transverse and coronal reformations (not significant), respectively. Visualization rates for portion or all of appendix were higher for combined transverse and coronal reformations than for transverse reformations alone (higher mean confidence scores: 0.23 higher [P < .009] and 0.51 higher [P < .001], respectively). In patients without appendicitis, transverse and coronal reformations together enhanced confidence in exclusion of wall thickening, distention, and fluid (lower confidence scores: 0.21 lower [P < .001], 0.17 lower [P < .01], 1.00 lower [P < .001], respectively). Combined transverse and coronal reformations enhanced confidence in identification of appendix in mean of 57 patients. Combined transverse and coronal scans helped exclude appendicitis in mean of 38 patients and aided diagnosis of it in 15.”
    Acute appendicitis: added diagnostic value of coronal reformations from isotropic voxels at multi-detector row CT.
    Paulson EK et al.
    Radiology. 2005 Jun;235(3):879-85.
  • “ In patients without appendicitis, transverse and coronal reformations together enhanced confidence in exclusion of wall thickening, distention, and fluid (lower confidence scores: 0.21 lower [P < .001], 0.17 lower [P < .01], 1.00 lower [P < .001], respectively). Combined transverse and coronal reformations enhanced confidence in identification of appendix in mean of 57 patients. Combined transverse and coronal scans helped exclude appendicitis in mean of 38 patients and aided diagnosis of it in 15.”
    Acute appendicitis: added diagnostic value of coronal reformations from isotropic voxels at multi-detector row CT.
    Paulson EK et al.
    Radiology. 2005 Jun;235(3):879-85.
  • “ Acute appendicitis is the most common cause of abdominal pain requiring urgent surgery in the United States. The clinical diagnosis can be difficult in patients with atypical presentations and, over the past several decades, computed tomography (CT) has been increasingly utilized to improve diagnostic accuracy. Helical CT has proven to be an excellent tool in the work-up of acute abdominal pain with a diagnostic accuracy for acute appendicitis of 93-99%. However, occasionally there are equivocal or false positive or negative cases, often due to non-visualization of the appendix. The development of multi-detector row CT and recent advancements in reconstruction software has allowed rapid, high-resolution imaging of the entire abdomen and pelvis resulting in multiplanar reformations (MPR) with a spatial resolution similar to that of the axial plane. This article reviews the utility of CT in suspected acute appendicitis and the potential added diagnostic value of coronal reformations in confirming or excluding the diagnosis.”
    “Helical CT has proven to be an excellent tool in the work-up of acute abdominal pain with a diagnostic accuracy for acute appendicitis of 93-99%. However, occasionally there are equivocal or false positive or negative cases, often due to non-visualization of the appendix. The development of multi-detector row CT and recent advancements in reconstruction software has allowed rapid, high-resolution imaging of the entire abdomen and pelvis resulting in multiplanar reformations (MPR) with a spatial resolution similar to that of the axial plane. This article reviews the utility of CT in suspected acute appendicitis and the potential added diagnostic value of coronal reformations in confirming or excluding the diagnosis.”
    MDCT of acute appendicitis: value of coronal reformations.
    Neville AM, Paulson EK
    Abdom Imaging. 2009 Jan-Feb;34(1):42-8.
  • CT of Suspected Appendicitis: The KEY
    - Water as oral contrast
    - IV contrast (3-5 cc/sec) and 40 second delay till scanning
    - Reconstruct thin (<1 mm) section for better spatial resolution on reconstructed datasets
    - Review in coronal display (saggital and 3D VRT may also be useful)
  • “In conclusion, the diagnostic evaluation of CCT showed significantly superiority than that of NCT. Intravenous contrast administration could also increase ease in identifying appendixes. Performing CT with intravenous contrast material for diagnosing APP would be necessary for adult ER patients, which might improve the care of ED patients by decreasing the time to diagnosis and disposition by promoting initially appropriate management to reduce the use of hospital resources.”
    Whether Intravenous Contrast is Necessary for CT Diagnosis of Acute Appendicitis in Adult ED Patients-
    Chui YH et al.
    Acad Radiol 2013; 20:73-78
  • “The diagnostic sensitivity of CCT was significantly better than that of NCT. Intravenous contrast administration could also make doctors easier in identifying appendices.”
    Whether Intravenous Contrast is Necessary for CT Diagnosis of Acute Appendicitis in Adult ED Patients-
    Chui YH et al.
    Acad Radiol 2013; 20:73-78
  • CT of Suspected Appendicitis: Contrast Protocols
    - Oral contrast only (positive or negative)
    - IV contrast only
    - Rectal contrast only
    - Oral (positive or negative) and IV contrast
    - Oral and IV and rectal contrast
  • CT of Suspected Appendicitis: Study Prep Time
    - None
    - 15-30 minutes
    - 60-90 minutes
    - 2 hours
    - 3 hours
  • “ In adult patients clinically suspected of having acute appendicitis, abdominopelvic CT frequently identifies an alternative cause for symptoms, which often requires hospitalization and surgery for treatment.”
    Alternative Diagnoses to Suspected Appendicitis at CT
    Pooler BD et al.
    Radiology 2012; 265:733-742
  • “ Of 1571 adults referred to CT for clinically suspected acute appendicitis, a CT diagnosis of appendicitis was made in 23.6%, compared with 31.6% who had an alternative cause for symptoms identified at CT.”
    Alternative Diagnoses to Suspected Appendicitis at CT
    Pooler BD et al.
    Radiology 2012; 265:733-742
  • “ In 406 patients in whom a specific alternative diagnosis was recorded by the treating clinician after CT was performed, the final clinical diagnosis was in agreement with the initial CT diagnosis 94.3% of the time.”Alternative Diagnoses to Suspected Appendicitis at CT
    Pooler BD et al.
    Radiology 2012; 265:733-742
  • “ In 704 patients for whom CT results did not suggest a specific diagnosis, the treating clinician did not arrive at a specific diagnosis 82.7% of the time.”
    Alternative Diagnoses to Suspected Appendicitis at CT
    Pooler BD et al.
    Radiology 2012; 265:733-742
  • “ Our findings show that, in cases of clinically suspected acute appendicitis, nonfocused abdominopelvic CT can efficiently and reliably identify a wide range of alternative causes for symptoms, in addition to confirming or ruling out appendicitis.”
    Alternative Diagnoses to Suspected Appendicitis at CT
    Pooler BD et al.
    Radiology 2012; 265:733-742
  • Alternative Diagnosis (men)
    - Gastroenteritis, colitis or adenitis (11.2%)
    - Urolithiasis (9.7%)
    - Diverticulitis (6.0%)
    - SBO (2.9%)
    - IBD (2.6%)
    - Cholecystitis (2.0%)
    - Pancreatitis (1.7%)
  • Alternative Diagnosis (Woman)
    - Benign adnexal mass w/ or w/o torsion (18.3%)
    - Gastroenteritis, colitis or adenitis (9.1%)
    - Urolithiasis (5.2%)
    - Constipation (4.2%)
    - Diverticulitis (3.3%)
    - Cholecystitis (2.9%)
    - IBD (2.5%)
    - SBO (2.3%)
  • “ In conclusion, CT frequently identifies an alternative cause for symptoms in adults clinically suspected of having acute appendicitis. These conditions often require hospitalization and invasive treatment, and diagnostic CT plays an instrumental role in the triage and treatment of these patients.”
    Alternative Diagnoses to Suspected Appendicitis at CT
    Pooler BD et al.
    Radiology 2012; 265:733-742
  • “ After the intervention, mean ED LOS among oral contrast eligible patients decreased by 97 min. Mean time from order to CT decreased by 66 minutes. No patient with CT Negative for acute findings had additional subsequent AP imaging within 72 h at our institution that led to a change in diagnosis.”
    Eliminating routine oral contrast use for CT in the emergency department: impact on patient throughput and diagnosis
    Levenson RB et al.
    Emerg Radiol (2012) 19:513-517
  • “ Preoperative MDCT generally allows for efficient and confident inclusion or exclusion of appendicitis, resulting in reduced rates of perforation and negative findings at appendectomy, as well as providing an alternative explanation in many cases without appendicitis.”
    Diagnostic Performance of Multidetector Computed Tomography for Suspected Acute Appendicitis
    Pickhardt PJ et al.
    Ann Intern Med 2011;154:789-796
  • “ 675 of 2871 (23.5%) had confirmed acute appendicitis. The sensitivity, specificity, and negative and positive predictive values of MDCT were 98.5%, 98.0%, 99.5% and 93.9% respectively.”
    Diagnostic Performance of Multidetector Computed Tomography for Suspected Acute Appendicitis
    Pickhardt PJ et al.
    Ann Intern Med 2011;154:789-796
  • “ 675 of 2871 (23.5%) had confirmed acute appendicitis. The sensitivity, specificity, and negative and positive predictive values of MDCT were 98.5%, 98.0%, 99.5% and 93.9% respectively. The overall negative findings at appedectomy was 7.5% but would have been decreased to 4.1% had surgery been avoided in 26 cases with true negative findings on MDCT.”
    Diagnostic Performance of Multidetector Computed Tomography for Suspected Acute Appendicitis
    Pickhardt PJ et al.
    Ann Intern Med 2011;154:789-796
  • “The overall negative findings at appedectomy was 7.5% but would have been decreased to 4.1% had surgery been avoided in 26 cases with true negative findings on MDCT.”
    Diagnostic Performance of Multidetector Computed Tomography for Suspected Acute Appendicitis
    Pickhardt PJ et al.
    Ann Intern Med 2011;154:789-796
  • “Multidetector computed tomography provided or suggested an alternative diagnosis in 893 of 2122 patients (42.1%) without appendicitis or appendectomy.”
    Diagnostic Performance of Multidetector Computed Tomography for Suspected Acute Appendicitis
    Pickhardt PJ et al.
    Ann Intern Med 2011;154:789-796
  • "Five of 13 patients with CT findings of appendicitis and reassuring clinical evaluation results in whom immediate treatment was deferred ultimately returned with appendicitis. In patients with CT results positive for appendicitis and benign or atypical clinical findings, a diagnosis of chronic or recurrent appendicitis may be considered."

    Acute Appendicitis: Clinical Outcomes in Patients with an Initial False Positive CT Diagnosis
    Stengel JW et al.
    Radiology 2010; 256:119-126

  • Implications for Patient Care 

    "The decision to forego surgery in patients with CT findings compatible with appendicitis but reassuring surgical evaluation findings often results in missed appendicitis and increased risk of perforation."

    Acute Appendicitis: Clinical Outcomes in Patients with an Initial False Positive CT Diagnosis
    Stengel JW et al.
    Radiology 2010; 256:119-126

  • "As radiologists, radiation protection is one of our primary concerns, as we also ensure that each patient recieves the most accurate examination for the clinical problem. Radiation exposure is reduced by judicious and appropriate use if imaging modalities; in our quest to reduce stochastic risks, unnecessary surgery and a ruptured appendix are not the most appropriate alternatives."

    CT and US in the Diagnosis of Appendicitis: An Argument for CT
    Hernanz-Schulman,M
    Radiology 2010; 255:3-7

  • "In conclusion, in patients presenting with acute nontraumatic abdominal pain, there is no statistically significant difference in specificity for diagnosing appendicitis identified in our study between CT scans obtained after the administration of oral and IV contrast media versus those obtained with the use of only IV contrast material."

    Abdominal 64-MDCT for Suspected Appendicitis: The Use of Oral and IV Contrast Material Versus IV Contrast Material Only
    Anderson SW et al.
    AJR 2009; 193:1282-1288

  • "Patients presenting with nontraumatic abdominal pain imaged using 64-MDCT with isotropic reformations had similar characteristics for the diagnosis of appendicitis when IV contrast material alone was used and when oral and IV contrast media was used."

    Abdominal 64-MDCT for Suspected Appendicitis: The Use of Oral and IV Contrast Material Versus IV Contrast Material Only
    Anderson SW et al.
    AJR 2009; 193:1282-1288

  • "Visualization of the appendix depended predominately on the reader rather than on the use of IV, oral, or oral and IV contrast agents or on radiation dose."

    MDCT for Suspected Acute Appendicitis in Adults: Impact of Oral and IV Contrast Media at Syandard Dose and Simulated Low Dose Techniques
    Heyzer C et al.
    AJR 2009; 193:1272-1281

  • "Diagnostic correctness is much more influenced by the reader than by the use of contrast medium (oral,IV, or both) or of simulated low dose radiation technique."

    MDCT for Suspected Acute Appendicitis in Adults: Impact of Oral and IV Contrast Media at Syandard Dose and Simulated Low Dose Techniques
    Heyzer C et al.
    AJR 2009; 193:1272-1281

  • "The decision to forego surgery in patients with CT findings compatible with appendicitis but reassuring surgical evaluation findings often results in missed appendicitis and increased risk of perforation."

    Acute Appendicitis: Clinical Outcome in Patients with an Initial False-Positive Diagnosis
    Stengel JW et al
    Radiology 2010: 000:1-8

  • "Five of 13 patients with CT findings of appendicitis and reassuring clinical evaluation results in whom immediate treatment was deferred ultimately returned with appendicitis.In patients with CT results positive for appendicitis and benign or atypical clinical findings a diagnosis of chronic or recurrent appendicitis may be considered."

    Acute Appendicitis: Clinical Outcome in Patients with an Initial False-Positive Diagnosis
    Stengel JW et al
    Radiology 2010: 000:1-8

  • What if the CT scan suggests appendicitis but the surgeon says the patient does not? Who is going to be correct?
    - The surgeon
    - The radiologist
    - No one consistantly
  • "While appendicitis could undoubtedly occur in an isodense appendix between 6 and 10 mm in diameter, such an appearance can occur in up to 6.6% of the normal population."

    The equivocal appendix at CT: prevalence n a control population
    Webb EM et al.
    Emerg Radiol (2010) 17;57-61

  • "In summary, our study found that while the outer wall-to-outer wall diameter of the normal appendix is frequently greater than 6 mm, none had a diameter greater than 10 mm in combination with equivocal mophology."

    The equivocal appendix at CT: prevalence n a control population
    Webb EM et al. Emerg Radiol (2010) 17;57-61

     

  • "Rising utilization of preoperative CT and advances in technology coincided with a decrease in the negative appendectomy rate for woman 45 years and younger but not in men of any age or woman older than 45 years."

    Making the Diagnosis of Acute Appendicitis: Do More Preoperative CT Scans Mean Fewer Negative Appendectomies? A 10-year Study
    Coursey CA et al.
    Radiology 2010; 254:460-468

     

  • "We believe our study, along with the results of prior studies, supports the use of preoperative CT particularly in the evaluation of woman of reproductive age suspected of having acute appendicitis."

    Making the Diagnosis of Acute Appendicitis: Do More Preoperative CT Scans Mean Fewer Negative Appendectomies? A 10-year Study
    Coursey CA et al.
    Radiology 2010; 254:460-468

  • "The percentage of patients undergoing CT prior to appendectomy increased from 18.5% (10 of 54) in 1998 to 94.2% (97 of 103) in 2007."

    Making the Diagnosis of Acute Appendicitis: Do More Preoperative CT Scans Mean Fewer Negative Appendectomies? A 10-year Study
    Coursey CA et al.
    Radiology 2010; 254:460-468

  • "As preoperative CT use increased, the negative appendectomy rate in woman 45 years of age and younger decreased from 42.9% to 7.1%."

    Making the Diagnosis of Acute Appendicitis: Do More Preoperative CT Scans Mean Fewer Negative Appendectomies? A 10-year Study
    Coursey CA et al.
    Radiology 2010; 254:460-468

     

  • "The improved confidence in visualizing appendiceal and periappendiceal findings eventually resulted in increased confidence in diagnosing appendicitis."

    MDCT with Coronal Reconstruction: Clinical Benefit in Evaluation of Suspected Acute Appendicitis in Pediatric Patients
    Kim YJ et al
    AJR 2009; 192:150-152

  • "In pediatric patients with suspected appendicitis, the addition of coronal reformatted scans to axial images in MDCT increases confidence in the diagnosis or exclusion of acute appendicitis."

    MDCT with Coronal Reconstruction: Clinical Benefit in Evaluation of Suspected Acute Appendicitis in Pediatric Patients
    Kim YJ et al
    AJR 2009; 192:150-152

  • "If workstation and network constraints limit a departments capacity to manage 2x1 mm sections, the study results indicate that the thinnest feasible sections (e.g.3x3 mm rather than 5x5 mm) should be used for the best possible interpretive confidence."

    MDCT for Suspected Appendicitis: Effect of reconstruction Section Thickness on Diagnostic Accuracy, Rate of Appendiceal Visualization, and Reader Confidence using Axial Images
    Johnson PT, Horton KM, Kawamoto S et al.
    AJR 2009; 192:893-901

     

  • "Correctness of diagnosis was not significantly associated with reconstruction method. However, for correctly diagnosed cases as normal, impression confidence increased with progressively thinner section thickness (p<0.001 for 5x5 vs 3x3 and 3x3 vs 2x10)."

    MDCT for Suspected Appendicitis: Effect of reconstruction Section Thickness on Diagnostic Accuracy, Rate of Appendiceal Visualization, and Reader Confidence using Axial Images
    Johnson PT, Horton KM, Kawamoto S et al.
    AJR 2009; 192:893-901

  • "Medical literature (from 1986-2004) were searched for articles on studies that used US,CT or both as diagnostic tests for appendicitis in children (26 studies, 9356 participants) or adults (31 studies, 4341 participants)."

    US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta Analysis Doria AS et al Radiology 2006; 241:83-94
  • "From the diagnostic performance perspective, CT had a significantly higher sensitivity than did US in studies of children and adults; from the safety perspective, however, one should consider the radiation associated with CT, especially in children."

    US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta Analysis
    Doria AS et al
    Radiology 2006; 241:83-94
  • "CT has a significantly higher sensitivity than does US for the diagnosis of appendicitis in adults and children; we should note that the sensitivity of US is reasonably high in children and that radiation issues are of special concern in this age group."

    US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta Analysis
    Doria AS et al
    Radiology 2006; 241:83-94
  • "Pooled sensitivity and specificity for diagnosis of appendicitis in children were 88% and 94%, respectively, for US studies and 94% and 95% respectively for CT studies."

    US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta Analysis
    Doria AS et al
    Radiology 2006; 241:83-94
  • "Pooled sensitivity and specificity for diagnosis of appendicitis in adults were 83% and 93%, respectively, for US studies and 94% and 94% respectively for CT studies."

    US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta Analysis
    Doria AS et al
    Radiology 2006; 241:83-94
  • "Unenhanced focused single detector CT and graded compression sonography performed in a general community teaching hospital by both body imaging radiologists and general radiology staff members have a similar accuracy for the diagnosis of acute appendicitis."

    Comparison of CT and Sonography in the Diagnosis of Acute Appendicitis: A Blinded Perspective Study
    Poortman P et al.
    AJR 2003:181:1355-1359
  • "147 patients had acute appendicitis at surgery and 67 patients did not. The sensitivity of CT and sonography were 76% and 79% respectively; the specificity was 83% and 78%, the accuracy was 78% and 78%."

    Comparison of CT and Sonography in the Diagnosis of Acute Appendicitis: A Blinded Perspective Study
    Poortman P et al.
    AJR 2003:181:1355-1359
  • Comparison of CT and Sonography in the Diagnosis of Acute Appendicitis: A Blinded Perspective Study

    Poortman P et al.
    AJR 2003:181:1355-1359
    noted limitations of this study: this study used a single detector scanner with 5 mm x 5 mm protocol and no oral, IV or rectal contrast
  • "In conclusion, this review illustrates the sonographic and CT features of a broad spectrum of nonsurgical diseases that may clinically present as appendicitis in patients without appendicitis. A correct imaging diagnosis of these alternative disorders may have a major impact on patient management because it prevents an unnecessary operation or hospitalization."

    Mimics of Appendicitis: Alternative Nonsurgical Diagnoses with Sonography and CT
    van Breda Vriesman et al
    AJR 2006;186:1103-1112
  • "In conclusion, this review illustrates the sonographic and CT features of a broad spectrum of nonsurgical diseases that may clinically present as appendicitis in patients without appendicitis."

    Mimics of Appendicitis: Alternative Nonsurgical Diagnoses with Sonography and CT
    van Breda Vriesman et al
    AJR 2006;186:1103-1112
  • GI Mimics of Appendicitis

    - Mesenteric adenitis
    - Infectious enterocolitis
    - Epiploic appendages
    - Omental infarction
    - Right sided diverticulitis
    - Crohns disease
    - Meckels divericulum
    - Ileocecal intussuception
  • Non-GI Mimics of Appendicitis

    - Pelvic inflammatory disease
    - Renal or ureteral stone disease
    - Rectus hematoma
    - Psoas abscess or hematoma
  • "Mortality and morbidity rates for removal of a normal appendix are 0.14% and 4.6%, respectively,but increase to 0.24% and 6.1% for acute appendicitis and up to 1.7% and 19% for perforated appendicitis."

    CT and Sonography for Suspected Acute Appendicitis: A Commentary
    Jacobs JE
    AJR 2006;1861094-1096
  • "The current accepted negative laparotomy rate is 10-15% but negative laparotomy rates can be much higher in woman of child bearing age."

    CT and Sonography for Suspected Acute Appendicitis: A Commentary
    Jacobs JE
    AJR 2006;1861094-1096
  • "There was no significant difference between the performance of intravenous contrast enhanced CT and that of rectal and intravenous enhanced CT in children suspected of having appendicitis."

    Suspected Appendicitis in Children: Rectal and Intravenous Contrast-enhanced versus Intravenous Contrast-enhanced CT
    Kharbanda AB et al.
  • "Intravenous and rectal contrast enhanced CT had a sensitivity of 92%, a specificity of 87%, a negative predictive value of 94% and an accuracy of 89%.Intravenous contrast enhanced CT had a sensitivity of 93%, a specificity of 92%, a negative predictive value of 95%, and an accuracy of 92%."

    Suspected Appendicitis in Children: Rectal and Intravenous Contrast-enhanced versus Intravenous Contrast-enhanced CT
    Kharbanda AB et al.
  • "Intravenous contrast enhanced CT had a sensitivity of 93%, a specificity of 92%, a negative predictive value of 95%, and an accuracy of 92%."

    Suspected Appendicitis in Children: Rectal and Intravenous Contrast-enhanced versus Intravenous Contrast-enhanced CT
    Kharbanda AB et al.
  • "Acute appendicitis is one of the most common causes of acute abdominal pain, the most common condition that requires abdominal surgery in childhood, and the most common condition associated with lawsuits among emergency physicians."

    CT Evaluation of Appendicitis and Its Complications:Imaging Techniques and Key Diagnostic Findings
    Leite NP et al.
    AR 2005;185:406-417
  • Ultrasound and Appendicitis

    - Success dependent on skill of operator
    - Difficult in large patients
    - Difficult if patient is in pain or uncooperative
    - May not define normal appendix or perforated appendix (both at extreme of appearances)
  • CT Protocols for Appendicitis

    - Unenhanced CT (no oral, no IV contrast)
    - Oral contrast only
    - IV contrast only
    - Oral and IV contrast
    - Rectal contrast only
    - Rectal contrast w/ oral and/or IV contrast
  • How are CT scans for suspected appendicitis reviewed?

    - Axial images
    - Multiplanar images (especially coronal display)
    - 3D images (mainly VRT)
  • "The sensitivity for diagnosing appendicitis based on the coronal images alone was 96%, the specificity was 100% and the accuracy was 98%. Coronal reformations decreased the number of images by 19%. CT diagnosis of appendicitis based on the coronal images is accurate."

    MDCT diagnosis of appendicitis using only coronal reformations
    Yaghmai V et al.
    Emerg Radiol (2007) 14:167-172 (4MDCT Scanner)
  • "The sensitivity for diagnosing appendicitis based on the coronal images alone was 96%, the specificity was 100% and the accuracy was 98%. CT diagnosis of appendicitis based on the coronal images is accurate."

    MDCT diagnosis of appendicitis using only coronal reformations
    Yaghmai V et al.
    Emerg Radiol (2007) 14:167-172 (4MDCT Scanner)
  • Appendicitis:Complications

    - Perforation- more common in patients with appendoliths as appendoliths seem to increase probability of perforation
    - Periappendiceal abscess- most frequent complication of perforation
    - Peritonitis- more common in younger patients
  • Appendicitis:Complications

    - Bowel obstruction
    - Septic seeding of mesenteric vessels
    - Gangrenous appendicitis
    - CT Evaluation of Appendicitis and Its Complications:Imaging Techniques and Key Diagnostic FindingsLeite NP et al.AR 2005;185:406-417
  • "Although certain multidetector CT findings are very specific for the diagnosis of perforated appendicitis, overall multidetector CT sensitivity is poor. Unless abscess or extraluminal gas is present, multidetector CT cannot enable the diagnosis of perforation."

    Perforated versus Nonperforated Acute Appendicitis: Accuracy of Multidetector CT Detection
    Bixby SD et al.
    Radiology 2006;241:780-786
  • CT Findings of Perforated Appendix

    - Extraluminal gas
    - Abscess
    - Small bowel ileus
    - Peritonitis
    - Appendicolith
    - Free fluid
    - Mesenteric lymph nodes
    - Cecal wall thickening
  • CT Findings of Perforated Appendix with Specificity of greater than 90%

    - Extraluminal gas
    - Abscess
    - Small bowel ileus
    - Peritonitis
    - Appendicolith
    - Free fluid
    - Mesenteric lymph nodes
    - Cecal wall thickening
  • Mucocele of the Appendix: facts

    - Well capsulated cystic mass in the pericecal region which is the distended appendiceal lumen caused by abnormal mucous accumulation
    - The mass may contain calcifications and enhance with IV contrast material
  • "Sensitivity of helical CT for suspected appendicitis in children improved significantly with abdominal contrast enhanced CT compared with limited area non-enhanced CT."

    Suspected Appendicitis in Children: Diagnosis with Contrast-enhanced versus Nonenhanced Helical CT
    Kaiser S et al.
    Radiology 2004;231:427-433
  • "Sensitivity of helical CT for suspected appendicitis in children improved significantly with abdominal contrast enhanced CT compared with limited area non-enhanced CT. No further improvement in sensitivity was achieved with the combination of both sequences in comparison to that with contrast enhanced CT only."

    Suspected Appendicitis in Children: Diagnosis with Contrast-enhanced versus Nonenhanced Helical CT
    Kaiser S et al.
    Radiology 2004;231:427-433
  • "Readers diagnosed appendicitis with 66% spooled sensitivity and 96% pooled specificity with limited area nonenhanced CT. With contrast enhanced CT of the entire abdomen appendicitis was diagnosed with 90% pooled sensitivity and 94% pooled specificity."

    Suspected Appendicitis in Children: Diagnosis with Contrast-enhanced versus Nonenhanced Helical CT
    Kaiser S et al.
    Radiology 2004;231:427-433
  • Mesenteric Adenitis: Key Facts

    - Benign self limiting inflammation of right sided mesenteric lymph nodes without an identifiable underlying inflammatory process
    - More common in children
    - Key is to visualize a normal appendix
© 1999-2020 Elliot K. Fishman, MD, FACR. All rights reserved.