04:03 PM Abstract No. 342 Utility of second look imaging in patients with persistent clinical concern for lower gastrointestinal bleed after initial negative CTA

Abstract

Patients with lower gastrointestinal bleed (LGIB) primarily receive computed tomography angiography (CTA) as their initial diagnostic test. A negative initial CTA can be challenging for the clinical team as these patients can become acutely unstable without a source of bleeding. This study aims to evaluate the utility of second look imaging in patients with persistent clinical concern for LGIB after initial negative CTA. This is a retrospective study of 278 patients who presented with LGIB and received an initial CTA. All patients presented to the ER or as inpatients with the following clinical signs or symptoms for LGIB: 90 of 278 (32%) nonspecific symptoms, 57 of 278 (21%) postoperative, 52 of 278 (19%) bright red blood per rectum, 34 of 278 (12%) pain, 16 of 278 (6%) melena, 8 of 278 (3%) mass, 7 of 278 (3%) hematochezia, 5 of 278 (2%) diverticulitis, 2 of 278 (1%) IBD, 1 of 278 (<1%) AVM. For patients with multiple scan during a single admission, the first CTA performed with concern for LGIB was used in the dataset. Our imaging protocol includes non-contrast, arterial, and portal venous phases. After an negative initial CTA, 28 of 278 (10%) patients received second look imaging with CTA, NM bleeding scan, or catheter-directed angiography during a single hospital admission for persistent concern for LGIB. The results of the second look imaging is as follows: 22 of 28 (79%) patients with negative CTA, 3 of 28 (11%) patients with negative NM bleeding scan, 2 of 28 (7%) patients had negative catheter-directed angiography, and 1 of 28 (4%) patients with positive NM bleeding scan. Overall, 27 of 28 (96%) of patients with negative initial CTA demonstrated a negative second look imaging. 7 of 33 patients with positive or negative initial CTA proceeded to catheter-directed angiography. Three of these patients received second look CTA, with 100% negative for active hemorrhage. The utility of second look imaging is limited in patients with persistent clinical concern for LGIB after initial negative CTA.