With a 100% consensus, the experts recommended noncontrast images for CTA performed on single-energy CT. This can be replaced by virtual noncontrast reconstructions with dual-energy CT [20,21]. In a meta-analysis of 22 studies evaluating accuracy of CTA for the diagnosis of active GIB (total of 672 patients), CTA had a sensitivity and specificity of 85% and 92%, respectively. Frequently, multiphase acquisition is performed, with a portal venous or a delayed phase (typically acquired during 70-90 sec window after the initiation of the contrast bolus injection) in addition to the angiographic phase [7,20]. In a study evaluating different CT imaging protocols, multiphasic CT protocols (unenhanced + arterial + portal venous phase) had the highest sensitivity of 92% for the detection of GIB compared with 83% for unenhanced phase with arterial or portal venous phase alone [18]. Oral contrast is usually not given for GIB studies because a positive oral contrast will render the examination nondiagnostic, and oral water can dilute intraluminal hemorrhage [7]. In an 8-year follow-up study after initial negative CT for suspected GIB, nearly 60% of patients with suspected UGIB, and nearly 77% patients with suspected lower GIB did not rebleed, suggesting relatively higher odds of rebleeding for UGIB compared with lower GIB despite a negative CTA [22]. In a retrospective study among patients with positive CTA for GIB, greater contrast extravasation volume on CT was significantly correlated with use of hemostatic therapy, intraprocedural active bleeding, and massive transfusion. The extravasation volume, however, did not correlate with patient mortality [23]. CTA may still be underused for the diagnosis of GIB [24]. Compared with Tc-99m-labeled RBC scintigraphy, CTA can lead to faster triage of patients toward definitive treatment by angiography [25].
Nonvariceal Upper Gastrointestinal Bleeding. With a 100% consensus, the experts recommended noncontrast images for CTA performed on single-energy CT. This can be replaced by virtual noncontrast reconstructions with dual-energy CT [20,21]. In a meta-analysis of 22 studies evaluating accuracy of CTA for the diagnosis of active GIB (total of 672 patients), CTA had a sensitivity and specificity of 85% and 92%, respectively. Frequently, multiphase acquisition is performed, with a portal venous or a delayed phase (typically acquired during 70-90 sec window after the initiation of the contrast bolus injection) in addition to the angiographic phase [7,20]. In a study evaluating different CT imaging protocols, multiphasic CT protocols (unenhanced + arterial + portal venous phase) had the highest sensitivity of 92% for the detection of GIB compared with 83% for unenhanced phase with arterial or portal venous phase alone [18]. Oral contrast is usually not given for GIB studies because a positive oral contrast will render the examination nondiagnostic, and oral water can dilute intraluminal hemorrhage [7]. In an 8-year follow-up study after initial negative CT for suspected GIB, nearly 60% of patients with suspected UGIB, and nearly 77% patients with suspected lower GIB did not rebleed, suggesting relatively higher odds of rebleeding for UGIB compared with lower GIB despite a negative CTA [22]. In a retrospective study among patients with positive CTA for GIB, greater contrast extravasation volume on CT was significantly correlated with use of hemostatic therapy, intraprocedural active bleeding, and massive transfusion. The extravasation volume, however, did not correlate with patient mortality [23]. CTA may still be underused for the diagnosis of GIB [24]. Compared with Tc-99m-labeled RBC scintigraphy, CTA can lead to faster triage of patients toward definitive treatment by angiography [25].