Replacing true non-contrast imaging with DECT in GI bleeding demonstrates non-inferior diagnostic performance, reading time and confidence
摘要
To determine whether a dual-energy CT (DECT) protocol—including arterial and portal-venous phases, virtual non-contrast (VNC) images, and iodine maps—provides non-inferior diagnostic performance to a conventional triphasic CT protocol for gastrointestinal (GI) bleeding.
Materials and methodsIn this retrospective single-center diagnostic accuracy study, we included all patients who underwent triphasic abdominal CT for GI bleeding between September 2015 and June 2024. For each case, conventional and DECT datasets were generated. Three fellowship-trained abdominal radiologists and two residents independently assessed all cases for active GI bleeding. A consensus review served as the reference standard. Sensitivity and specificity were compared using the Wald method for paired confidence intervals (non-inferiority margin 3%). Diagnostic confidence and reading time were analyzed using the Wilcoxon signed-rank test. Inter-reader agreement was assessed with Fleiss’ kappa.
ResultsOne hundred patients (mean age, 70 ± 14 years; 34 women) were evaluated, including 50 with GI bleeding (21 upper, 29 lower) and 50 controls. With conventional triphasic CT, sensitivity and specificity were 91.6% and 94.4%, respectively. With DECT, they were 94.4% and 96.0%, demonstrating non-inferiority within a 3% margin. Diagnostic confidence increased from 4 (IQR, 4–5) to 5 (IQR, 4–5) (p < 0.01). Mean reading time decreased from 96.3 s to 93.6 s (p < 0.01), also meeting non-inferiority. Inter-reader agreement was almost perfect (κ = 0.82). Total DLP was reduced by 20% when true non-contrast images were omitted.
ConclusionDECT-derived VNC and iodine maps provide non-inferior diagnostic performance to conventional CT for GI bleeding and can replace true non-contrast imaging.
Key Points