Systematic review and meta‐analysis of the accuracy of MRI to diagnose appendicitis in the general population

Abstract

Purpose To perform a systematic review and meta-analysis of all published studies since 2005 that evaluate the accuracy of MRI for the diagnosis of acute appendicitis in the general population presenting to emergency departments. Materials and Methods All retrospective and prospective studies evaluating the accuracy of MRI to diagnose appendicitis published in English and listed in PubMed, Web of Science, Cinahl Plus, and the Cochrane Library since 2005 were included. Excluded studies were those without an explicitly stated reference standard, with insufficient data to calculate the study outcomes, or if the population enrolled was limited to pregnant women or children. Data were abstracted by one investigator and confirmed by another. Data included the number of true positives, true negatives, false positives, false negatives, number of equivocal cases, type of MRI scanner, type of MRI sequence, and demographic data including study setting and gender distribution. Summary test characteristics were calculated. Forest plots and a summary receiver operator characteristic plot were generated. Results Ten studies met eligibility criteria, representing patients from seven countries. Nine were prospective and two were multi-center studies. A total of 838 subjects were enrolled; 406 (48%) were women. All studies routinely used unenhanced MR images, though two used intravenous contrast-enhancement and three used diffusion-weighted imaging. Using a bivariate random-effects model the summary sensitivity was 96.6% (95% CI: 92.3%–98.5%) and summary specificity was 95.9% (95% CI: 89.4%–98.4%). Conclusion MRI has a high sensitivity and specificity for the diagnosis of appendicitis, similar to that reported previously for CT.

Contrast-Enhanced Abdominal MRI for Suspected Appendicitis: How We Do It

“…MRI combines the advantages of ultrasound (i.e., it is noninvasive and lacks ionizing radiation) with the high-resolution 3D cross-sectional information of CT [24]. A recent systematic review and meta-analysis of all published studies since 2005 that evaluateed the accuracy of MRI for the diagnosis of acute appendicitis in the general population presenting to emergency departments concluded that MRI has a high sensitivity and specificity for the diagnosis of appendicitis, similar to that reported previously for CT [25]. …”

Trends in the Use of Medical Imaging to Diagnose Appendicitis at an Academic Medical Center

“…In fact, there were only seven occurrences of its use in our study period. This utilization could possibly shift, however, given the number of recent articles highlighting the test accuracy of MRI in this situation (14–16). Additionally, our medical center does not have a labor and delivery service; pregnant patients are directed to another local hospital affiliated with our center.…”

“…Since the accuracy of ultrasound has been shown to be inferior to CT (10–12), its effect on negative laparotomy rates may be less when compared with CT. For example, a state-level registry study showed that NLR was 9.8% for patients with no imaging, 8.1% for those who had an ultrasound, and 4.5% for those who had a CT (13). Few studies have demonstrated the effect of MRI on NLR, though its accuracy for diagnosing appendicitis has been shown to be similar to CT (14–16). One center found that the NLR for pregnant women dropped from 55% to 29% when MRI was introduced into the diagnostic pathway (17).…”

Prospective evaluation of MRI compared with CT for the etiology of abdominal pain in emergency department patients with concern for appendicitis

“…Ultrasound has been proposed as one such alternative, but its use is hindered by a relatively high degree of operator dependence, a limitation reflected in the American College of Radiology's Appropriateness Criteria for Right Lower Quadrant Pain, which reserves recommendation for ultrasound to pediatric or pregnant patients . Emerging research has demonstrated encouraging results for the use of magnetic resonance imaging (MRI) to evaluate for appendicitis; two recent systematic reviews and meta‐analyses found pooled sensitivity and specificity of MRI in the evaluation of appendicitis to be ~96% …”