LAUSR

INTRODUCTION Peritoneal TB (PTB) is the commonest presentation of abdominal TB. One of its close mimics is peritoneal carcinomatosis (PC). We present a new sign of PTB on contrast enhanced multidetector computed tomography (CT) called the Omental Rim (CT-OR) sign which helps to accurately differentiate PTB from PC. MATERIALS AND METHODS A prospective study was performed from 2014 to 2018 on patients referred for CT at a tertiary referral hospital. The study group consisted of consecutive 85 patients, 52 men and 33women, with PTB. The control group consisted of 168 consecutive patients, 96 men and 72 women, with PC. The images were analysed for omental thickening and enhancement, peritoneal thickening and nodules, mesenteric thickening and nodules, presence, quantity, loculation and density of ascites, presence of nodes, bowel and other organ involvement as well as a new sign called the CT-OR sign. RESULTS The CT-OR sign could identify 85% of patients with PTB. It was absent in 96% of patients with PC and was effective in ruling out PC (p < 0.001). The sign had a sensitivity of 85%, specificity of 96%, positive predictive value of 92%, negative predictive value of 93% and accuracy of 92%. CONCLUSION The new CT-OR sign is a sensitive and specific sign for PTB. It helps to rule out majority of PC.