Diagnosis of Acute Gastrointestinal Bleeding: Comparison of the Arterial, the Portal, and the Combined Set Using 64-Section Computed Tomography Jin Woong Kim, MD,* Sang Soo Shin, MD,Þ Woong Yoon, MD,Þ Nam Kyu Chang, MD,* Suk Hee Heo, MD,Þ Yong Yeon Jeong, MD,Þ and Heoung Keun Kang, MDÞ Objectives: To compare the respective capabilities of the arterial, the portal, and the combined set in the detection and localization of acute gastrointestinal (GI) bleeding with 64-section computed tomography (CT). Methods: A total of 46 patients with acute GI bleeding and who had undergone both 64-section CT and digital subtraction angiography were included in this study. The results of angiography were used as a refer- ence standard. Two radiologists independently reviewed the 3 sets of CT images (arterial set, the unenhanced and arterial-phase images; portal set, the unenhanced and portal venous-phase images; combined set, the unenhanced and arterial-phase and portal venous-phase images). The diagnostic accuracy was assessed by a receiver operating characteristic analysis. Results: For each observer, the Az values were 0.915 and 0.931 for the arterial set, 0.903 and 0.933 for the portal set, and 0.919 and 0.911 for the combined set, respectively. The differences were not statistically signif- icant among the 3 data sets for each observer (P 9 0.05). Both observers correctly detected the bleeding site in 81.3% and 84.4% on the arterial set, in 81.3% and 84.4% on the portal set, and in 84.4% and 84.4% on the combined set, respectively. Conclusions: Using 64-section CT, the diagnostic performance was not different among the arterial, the portal, and the combined set for the detection and localization of acute GI bleeding. Key Words: gastrointestinal bleeding, multidetector-row computed tomography, examination protocol, diagnostic accuracy, angiography (J Comput Assist Tomogr 2011;35: 206Y211) A cute gastrointestinal (GI) bleeding is a medical emergency and a major cause of morbidity and mortality. 1 In dealing with acute GI bleeding, it is of utmost importance to detect and localize the exact bleeding site. Although it is generally agreed on that the initial clinical evaluation could localize the bleeding site to the upper or lower GI tract, depending on he- matemesis, hematochezia, and melena, such a rough localization is neither accurate nor practically beneficial. 2 Instead, several di- agnostic modalities, such as endoscopy, multidetector-row com- puted tomography (MDCT), digital subtraction angiography, and 99m Tc-red blood cell scintigraphy, have been used for this pur- pose. The MDCT is currently emerging as the first-line imaging tool to effectively reveal the bleeding site in patients with acute GI bleeding. 2Y8 The rapid advances in CT technology have enabled MDCT to directly depict the bleeding site with excellent diagnostic ac- curacy. The superior diagnostic ability of MDCT for detecting the bleeding site in the GI tract could be attributed to the higher spatial and temporal resolution. 9 Several studies have recently demonstrated that MDCT could be the most valuable imaging technique for depicting the site as well as the presence of acute GI bleeding. 4,7,9Y15 However, most studies have focused on the diagnostic ac- curacy of MDCT as compared with that of other diagnostic modalities, and these studies used various scanning protocols. To the best of our knowledge, few studies have been conducted to determine the optimal scan phase of MDCT in patients with acute GI bleeding. 11,12 Therefore, the question regarding which type of scanning is suitable for detecting and localizing the bleeding site still remains to be determined. The purpose of this study was to retrospectively compare the respective capabilities of the arterial, the portal, and the combined set in the detection and localization of acute GI bleeding with 64-section CT using digital subtraction angiog- raphy as the standard of reference. MATERIALS AND METHODS Patient Population Our institutional review board approved this retrospective study, and the requirement for informed consent was waived. Between April 2005 and December 2007, through a computer- based search of the database of our hospital for patients with GI bleeding, a total of 139 consecutive patients who underwent both CT and digital subtraction angiography were enrolled for this study. Of them, 93 patients were excluded from the study: 76 patients underwent CT examination using CT other than 64-section CT (single-section helical CT, n = 48; 4-section CT, n = 28), 12 patients had chronic intermittent GI bleeding, and digital subtraction angiography was performed in 5 patients more than 24 hours after CT examination. Thus, 46 consecu- tive patients (29 men and 17 women; age range, 20Y93 years; mean age, 61 years) were finally included in this study. All the patients subsequently underwent digital subtraction angiogra- phy within 24 hours after their 64-section CT examination. Thirty-eight patients underwent endoscopic examination (eso- phagogastroduodenoscopy only, n = 18; colonoscopy only, n = 8; both esophagogastroduodenoscopy and colonoscopy, n = 12) before digital subtraction angiography. Of these patients, endo- scopic hemostasis was conducted in 14 patients, but this failed. For the patients who presented with hematemesis, melena, or hematochezia that occurred within 24 hours before CT ex- amination, these patients were regarded as having ‘‘acute’’ GI ORIGINAL ARTICLE 206 www.jcat.org J Comput Assist Tomogr & Volume 35, Number 2, March/April 2011 From the *Department of Radiology, Chonnam National University Hwasun Hospital, Jeollanam-do; and †Department of Radiology, Center for Aging and Geriatrics, Chonnam National University Medical School, Gwangju, South Korea. Received for publication September 12, 2010; accepted December 3, 2010. Reprints: Sang Soo Shin, MD, Department of Radiology, Chonnam National University Medical School, 8 Hack-dong, Dong-gu, Gwangju, 501-757, South Korea (e-mail: kjradsss@dreamwiz.com). This study was supported by a grant (CRI11060-1) from the Chonnam National University Hospital Research Institute of Clinical Medicine in South Korea. Copyright * 2011 by Lippincott Williams & Wilkins Copyright © 2011 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.