Toward an evidence-based step-up approach in diagnosing diverticulitis

Background. The lack of pathognomonic findings and the chance of complicated disease have resulted in the widespread use of additional imaging to diagnose acute colonic diverticulitis (ACD). The added value of additional imaging in the diagnostic workup of patients suspected of ACD is not well defined. Aims. The aim of this study was to systematically review the literature of the accuracy of the clinical evaluation and diagnostic modalities for patients with suspected ACD, to come to an evidence-based approach to diagnose ACD. Methods. A systematic review and meta-analysis of studies that reported diagnostic accuracy of the clinical diagnosis and diagnostic modalities in patients with suspected diverticulitis were performed. Study quality was assessed with the STARD checklist. True-positive, true-negative, false-positive, and false-negative findings were extracted and pooled estimates of sensitivity and specificity per diagnostic test were calculated, if applicable. Results. The overall quality of the studies reporting the diagnostic accuracy of the clinical diagnosis, contrast enema and magnetic resonance imaging (MRI) were moderate to poor and not suitable for meta-analysis. Sensitivity of the clinical diagnosis varied between 64% and 68%. Ultrasound (US) and computed tomography (CT) studies were eligible for meta-analysis. Summary sensitivity estimates for US were 90% (95% CI: 76-98%) versus 95% (95% CI: 91-97%) for CT (p = 0.86). Summary specificity estimates for US were 90% (95% CI: 86-94%) versus 96% (95% CI: 90-100%) for CT (p = 0.04). Sensitivity for MRI was 98% and specificity varied between 70% and 78%. Sensitivity of contrast enema studies varied between 80% and 83%. Conclusion. In two-thirds of the patients, the diagnosis of ACD can be made based on clinical evaluation alone. In one-third of the patients, additional imaging is a necessity to establish the diagnosis. US and CT are comparable in diagnosing diverticulitis and superior to other modalities. CT has the advantage of higher specificity and the ability to identify alternative diagnoses. The role of MRI is not yet clear in diagnosing ACD. Contrast enema is considered an obsolete imaging technique to diagnose ACD based on lower sensitivity and specificity than US and CT. A step-up approach with CT performed after an inconclusive or negative US, seems a logical and safe approach for patients suspected of ACD.