Muhammad Awais MBBS, Presenter: Nothing to Disclose

Tanveer Ul Haq MBBS, Abstract Co-Author: Nothing to Disclose

Zishan Haider MBBS, FRCR, Abstract Co-Author: Nothing to Disclose

Abdul Rehman MBBS, Abstract Co-Author: Nothing to Disclose

Maseeh Uz Zaman MBBS, Abstract Co-Author: Nothing to Disclose

Acute lower gastrointestinal bleeding (LGIB) is a medical and surgical emergency, which despite recent advances in diagnosis and treatment, still remains a diagnostic and therapeutic challenge causing significant morbidity and mortality. In this study, we assessed the diagnostic performance of RBC scintigraphy and CT with GI bleed protocol for the detection and localization of the LGIB.

Seventy six patients had undergone either RBC scintigraphy, CT with GI bleed protocol or both, followed within 24 hours by conventional angiography for the evaluation of LGIB between Jan 2010 and Feb 2014. All scintigraphic and CT examinations were performed according to standard departmental protocol. CT with GI protocol comprised of an initial unenhanced CT, followed by arterial, portovenous and delayed phases at 15, 60 and 180 seconds post intravenous contrast administration, respectively. Data was retrospectively reviewed for evaluating sensitivity, specificity and accuracy of these two modalities for the detection and localization of LGIB using conventional angiography as gold standard. Statistical analysis was performed on Statistical Analysis Software (SAS) version 9.1.3 and Fisher exact test was used to compare the sensitivity, specificity and overall accuracy of the two modalities. A p-value of less than 0.05 was considered statistically significant.

Fifty one (51) patients had undergone RBC Scintigraphy alone, 20 had CT with GI bleed protocol alone and 5 had undergone both the modalities. Fourteen (14) out of 25 patients in CT with GI bleed group had angiographic evidence of active bleed compared to 32 out of 56 patients in the RBC scintigraphy group. CT with GI bleed protocol had significantly higher specificity (90.9%) as compared to 33.3% for RBC scintigraphy. (p=0.0027) CT with GI bleed also had a higher sensitivity (100%) as compared RBC scintigraphy (81.25%). However, this difference did not reach statistical significance. (p=0.09) Overall accuracy of CT with GI bleed protocol (90.5%) was significantly higher as compared to 60.7% for RBC scintigraphy. (p=0.0006)

CT with GI bleed protocol was significantly more accurate in detecting and localizing lower GI bleed in comparison to RBC scintigraphy.

Patients with LGIB should undergo CT with GI bleed rather than RBC scintigraphy for detecting and localizing source of LGIB as it is more accurate and less time consuming.

Awais, M, Haq, T, Haider, Z, Rehman, A, Zaman, M, Comparison of Diagnostic Performance of 99mTc-Labeled RBC Scintigraphy and CT with GI Bleed Protocol in Detecting and Localizing Source of Acute Lower Gastrointestinal Bleeding Using Conventional Angiography as Gold Standard.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14002604.html