Urgent Computed Tomography for Determining the Optimal Timing of Colonoscopy in Patients with Acute Lower Gastrointestinal Bleeding

Abstract

Objective We evaluated the diagnostic performance of computed tomography (CT) as an initial radiologic test for assessing the optimal timing of colonoscopy in patients with acute lower gastrointestinal bleeding (LGIB) and investigated the effectiveness of contrast-enhanced (CE) CT for detecting colonic diverticular bleeding. Methods This was a retrospective study of 1,604 consecutive patients who visited or were referred to St. Marianna University Hospital due to acute LGIB and underwent colonoscopy within three months after presentation between September 2004 and December 2012. The clinicopathological data of the subjects were obtained from their medical records. Results Among the 1,604 patients presenting with LGIB, 879 (55%) underwent a CT scan. Elective colonoscopy was considered in cases in which typical colonic wall thickening was observed on CT, suggesting colonic inflammation or malignancy (239 patients; 27%). The diagnoses in the elective cases included ischemic colitis (38%), infectious colitis (8%), inflammatory bowel disease (8%) and malignancy (5%). Urgent colonoscopy was performed after the CT examination in 640 cases (73%). The most common presumptive CT diagnosis was diverticulum (402/640; 63%). Of the 638 patients who underwent CE-CT, diverticula were observed in 346 cases, including 104 cases of extravasation indicating ongoing diverticular bleeding. Among these 104 patients, the site of bleeding was identified in 71 subjects (68%) during colonoscopy. The rate of detection of the bleeding source on colonoscopy was significantly higher in the patients with extravasation on CE-CT than in those without extravasation on CE-CT (68% vs. 20%, respectively; p<0.001). Conclusion Urgent CT is useful for determining the optimal timing of colonoscopy in cases of acute LGIB. CE-CT may be used to depict the presence and location of active hemorrhage and provides useful information for subsequent colonoscopy, especially in patients with diverticular bleeding.

Guidelines for Colonic Diverticular Bleeding and Colonic Diverticulitis: Japan Gastroenterological Association

“…Conversely, bleeding diverticula were identified on colonoscopy in 60-68% of patients with extravasation on CE-CT (positive predictive value) and 20-31% of those without extravasation, demonstrating a higher identification rate in the former [67,69]. In one of the retrospective observational studies, CE-CT significantly improved the rate of identifying vascular lesions (35.7 vs. 20.6%; p = 0.01) and the rate of providing endoscopic therapy (34.9 vs. 13.4%; p < 0.01), with a high rate of agreement regarding the source of bleeding between CE-CT and colonoscopy (κ value: 0.83; p < 0.01) [68].…”

“…Quality of evidence: C Strength of recommendation: Probably do it Agreement rate: 75% Explanation Three retrospective observational studies [67][68][69] and one prospective observational study [70] have investigated whether pre-colonoscopy CE-CT improves the rate of identifying the source of bleeding and the diverticula with SRH in patients presenting with acute LGIB or colonic diverticular bleeding, showing a low rate of positive extravasation (15-36%) and a low sensitivity (20-52%) on CE-CT [67][68][69][70]. Conversely, bleeding diverticula were identified on colonoscopy in 60-68% of patients with extravasation on CE-CT (positive predictive value) and 20-31% of those without extravasation, demonstrating a higher identification rate in the former [67,69].…”

Management of Diverticular Hemorrhage: Catching That Culprit Diverticulum Red-Handed!

“…Extravasation of contrast medium was observed in 30% of all patients with LGIB and in 68% of the patients with CDH. In patients with CDH, CTA is mandatory before colonoscopy, because identifying the source of bleeding prior to surgery may result in less invasive urgent colonoscopy and more effective hemostasis [40]. For CTA, a total of 90 mL of iopamidol was power-injected intravenously at a rate of 1.5 mL/s.…”

“…The presence of diverticular bleeding on CTA was defined as follows: the visualization of colonic diverticula and extravasation of contrast material into the bowel lumen on arterial-phase images and/or abdominal colonic wall enhancement (Fig. 2) [40]. This CTbased test has largely replaced red blood cell-labeled scintigraphy at many centers as the first radiologic investigation and is sensitive for bleeding rates as low as 0.2 mL/ min [41].…”

“…Since CTA is rapid, noninvasive, and highly reproducible, it is commonly used in LGIB emergencies, although the optimal timing and patient characteristics for the diagnosis of colonic diverticular bleeding have not been established. Nakatsu et al [40] stressed that CTA is a useful initial radiological test for determining the optimal timing for colonoscopy in patients with acute LGIB. Emergency colonoscopy should be considered in cases of acute LGIB associated with extravasation of contrast material into the bowel lumen from colonic diverticula, as the rate of detection of the source of bleeding on urgent colonoscopy was very high in such cases in their study.…”