Discriminating complicated from uncomplicated appendicitis by ultrasound imaging, computed tomography or magnetic resonance imaging: systematic review and meta-analysis of diagnostic accuracy

Abstract

Background Discriminating complicated from uncomplicated appendicitis is crucial. Patients with suspected complicated appendicitis are best treated by emergency surgery, whereas those with uncomplicated appendicitis may be treated with antibiotics alone. This study aimed to obtain summary estimates of the accuracy of ultrasound imaging, CT and MRI in discriminating complicated from uncomplicated appendicitis Methods A systematic literature review was conducted by an electronic search in PubMed, Embase and the Cochrane Library for studies describing the diagnostic accuracy of complicated versus uncomplicated appendicitis. Studies were included if the population comprised adults, and surgery or pathology was used as a reference standard. Risk of bias and applicability were assessed with QUADAS-2. Bivariable logitnormal random-effect models were used to estimate mean sensitivity and specificity. Results Two studies reporting on ultrasound imaging, 11 studies on CT, one on MRI, and one on ultrasonography with conditional CT were included. Summary estimates for sensitivity and specificity in detecting complicated appendicitis could be calculated only for CT, because of lack of data for the other imaging modalities. For CT, mean sensitivity was 78 (95 per cent c.i. 64 to 88) per cent, and mean specificity was 91 (85 to 99) per cent. At a median prevalence of 25 per cent, the positive predictive value of CT for complicated appendicitis would be 74 per cent and its negative predictive value 93 per cent. Conclusion Ultrasound imaging, CT and MRI have limitations in discriminating between complicated and uncomplicated appendicitis. Although CT has far from perfect sensitivity, its negative predictive value for complicated appendicitis is high.

Can The ‘Speed Bump Sign’ Be a Diagnostic Tool for Acute Appendicitis? Evidence-Based Appraisal by Meta-Analysis and GRADE

“…The pooled sensitivity of the speed bump sign is similar to RIPASA score (94%, 95% CI = 92-95%) [22], indicating the value of the speed bump sign in clinical applications. In addition, unnecessary CT scans can be avoided because of the similar pooled sensitivity between speed bump sign and CT (95%, 95% CI = 93-96%) [29]; consequently, medical cost and radiation exposure can be reduced. Although a low CoE was evaluated by GRADE methodology in pooled sensitivity because of some RoB and heterogeneity, taking the history of the speed bump sign in cases of suspected AA is strongly recommended.…”

Preoperative predictors of extended resection in patients with complicated acute appendicitis undergoing surgery

“…Although the useful diagnostic modalities for acute appendicitis include ultrasonography, CT, and magnetic resonance imaging, CT is generally accepted as the most reliable tool for the diagnosis of appendicitis (20). A previous meta-analysis has reported that CT has relatively low sensitivity and high negative predictive value for complicated appendicitis (mean sensitivity : 78%, mean specificity : 91%, mean positive predictive value : 74%, mean negative predictive value : 93%) (21). In our study, the diagnostic accuracy of CT for complicated appendicitis was comparable to that reported in the abovementioned study, supporting the reliability of our findings.…”

Diagnosis of Uncomplicated and Complicated Appendicitis in Adults

“…A recent systematic review and meta-analysis from our group compared all available studies on imaging modalities differentiating between uncomplicated and complicated appendicitis ( 47 ). Eleven studies using CT were found.…”

“…Eleven studies using CT were found. Summary estimates were 78% for sensitivity and 91% for specificity, resulting in a PPV of 74% and an NPV of 93% for diagnosis of complicated appendicitis ( 47 ). Results were highly heterogeneous, with sensitivities ranging from 28% to 95% ( 47 ).…”

“…Summary estimates were 78% for sensitivity and 91% for specificity, resulting in a PPV of 74% and an NPV of 93% for diagnosis of complicated appendicitis ( 47 ). Results were highly heterogeneous, with sensitivities ranging from 28% to 95% ( 47 ). One study has described the discriminatory capability when an initial US is performed followed by a conditional CT or MRI in case of an inconclusive or negative US.…”