Serial assessment of computed tomography angiography for pulmonary and systemic arteries using a reduced contrast agent dose for the diagnosis of systemic artery-to-pulmonary artery shunts.

PURPOSE: To evaluate the diagnostic performance and feasibility of a modified computed tomography (CT) scan protocol, we performed a serial assessment of the computed tomography angiography for pulmonary artery (CTA-P) and systemic artery (CTA-S) (CTA-PS) using a reduced contrast agent dose to diagnose systemic artery-to-pulmonary artery shunts (SPSs). MATERIALS AND METHODS: Twenty-five patients who underwent multiphase contrast-enhanced chest CT and conventional chest angiography were included. Three image sets (CTA-P, CTA-S, and CTA-PS) were evaluated by two board-certified radiologists. The visualization of the CT image findings associated with SPSs, such as filling defects and enhancement in the pulmonary arteries, was evaluated using a 5-point scale. RESULTS: The diagnostic performance (sensitivity, specificity, and accuracy) of CT imaging findings associated with SPSs in CTA-P and CTA-PS were as follows: CTA-P, 57.1%, 87.5%, and 62.0%; CTA-PS, 81.0%, 100.0%, and 84.0%. CT findings associated with SPSs in CTA-P were significantly sensitive to the CTA-PS protocol. There were no significant differences between the CTA-S and CTA-PS protocols. The area under the curve (AUC) of the CT imaging findings associated with SPSs in the CTA-P and CTA-PS groups was 0.835 and 0.911, respectively (P = 0.191). The AUC of the CT imaging findings associated with SPSs in CTA-S and CTA-PS were 0.891 and 0.926, respectively (P = 0.373). CONCLUSION: CTA-PS using a reduced contrast agent dose protocol could improve the overall diagnostic confidence of SPSs, owing to better visualization of CT imaging findings associated with SPSs compared to individual assessments of CTA-P or CTA-S. Therefore, CTA-PS can be used as an alternative preembolization evaluation modality to conventional angiography in patients with hemoptysis suspected of having SPSs.

Rapid identification of source of delayed hemobilia following endoscopic metallic stenting for malignant biliary obstruction.

Delayed hemobilia, a rare but potentially fatal complication of endoscopic metallic stenting for malignant biliary obstruction, requires prompt identification of the source of bleeding and subsequent embolization. However, hemobilia is characteristically intermittent, and computed tomography (CT) often fails to show pseudoaneurysms or extravasations. In particular, because the posterior superior pancreaticoduodenal artery (PSPDA) runs alongside the common bile duct for its whole length, it is readily obscured by metallic artifacts in that duct, such as stents, making identification of the source of bleeding by CT difficult. We have encountered three patients with delayed hemobilia from the PSPDA following endoscopic biliary stenting for malignant biliary obstruction in whom no extravasation or pseudoaneurysms were detected by contrast-enhanced CT during bleeding. However, when we identified that the PSPDA had a smaller diameter than in previous CTs in all three cases, we suspected that the PSPDA was the source of the bleeding. No extravasation or pseudoaneurysms were detected with celiac arteriography or superior mesenteric arteriography; however, extravasation and pseudoaneurysms were detected by direct PSPDA angiography. Hemostasis was achieved through embolization. Detecting a large decrease in the diameter of the PSPDA on contrast-enhanced CT during biliary bleeding may help to identify the source of that bleeding.

Improvement in radiological reading efficiency and residents' education and clinical contribution using the modified reading system "Triage Reader".

PURPOSE: To assess whether the modified reading system "Triage Reader" (TR) can improve the radiological reading work environment. MATERIALS AND METHODS: This retrospective, single-center study analyzed two reading systems for 26,786 computed tomography and magnetic resonance imaging examinations. In the conventional system (January 1-May 31, 2016), all reading work was mostly completed within the day. In the TR system (January 1-May 31, 2017), a radiology resident (TR) first read every image immediately after the examination and tagged each examination according to actual image findings and clinical demands. Routine reading work was finished when all high-priority cases were completed. Low-priority cases were assessed the following day. RESULTS: When using the TR system, the mean reading number in the evening decreased (P = 0.009). The mean elapsed time to finalize report of case with actual urgent image finding shortened from 4.26 to 1.97 h (P < 0.0001). The mean number of cases experienced per resident increased from 5.4 to 28.7 (P < 0.001). Subjective evaluation revealed a significant improvement in "Reading efficiency" and "Contribution to clinical practice." CONCLUSION: Introduction of the TR system can improve the reading efficiency and quality, educational effect among residents by increasing the number of experienced cases and work satisfaction.