CT scan for early diagnosis of anastomotic leak after colorectal surgery: is rectal contrast useful?

Abstract

Computed tomography (CT) scan with rectal contrast enema (RCE-CT) could increase the detection rate of anastomotic leaks (AL) in the early postoperative period following colorectal surgery, compared to CT scan without RCE. The aim of this study was to assess the benefit of RCE-CT for the early diagnosis of AL following colorectal surgery. Patients who had a RCE-CT for suspected AL in the early postoperative period following colorectal surgery with anastomosis between January 2012 and July 2019 at the Dijon University Hospital were retrospectively included. All images were reviewed by two independent observers who were blinded to the original report. The reviewers reported for each patient whether an AL was present or not in each imaging modality (CT scan, then RCE-CT). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were then calculated to determine the diagnostic performance of each modality. One hundred and thirty-nine patients were included. RCE-CT had an increased NPV compared to CT scan (82% vs 77% (p = 0.02) and 84% vs 68% (p < 0.0001) for observers 1 and 2, respectively). RCE-CT had an increased sensitivity compared to CT scan (79% vs 48% (p < 0.0001) for observer 2). RCE-CT had a significant lower false-negative rate for both observers: 18% vs 23% (p = 0.02) and 16% vs 32% (p < 0.0001). RCE-CT improved the detection rates of AL in the early period following colorectal surgery. RCE-CT should be recommended when a CT scan is negative and AL is still suspected.