ObjectivesTo compare right gastric (RGA) and segment 4 artery (A4) origin detection rates during radioembolisation workup between early and late arterial phase liver CT protocols.Methods100 consecutive patients who underwent liver CT between May 2012–January 2015 with early or late arterial phase protocol (n = 50 each, 10- vs. 20-s post-threshold delay) were included. RGA/A4 origin detection rates, assessed by two raters, and contrast-to-noise ratio (CNR) of the hepatic artery relative to the portal vein were compared between the protocols.ResultsThe first–second rater scored the RGA origin as visible in 58–65 % (specific proportion of agreement 82 %, κ = 0.62); A4 origin in 96–89 % (94 %, κ = 0.54). Thirty-six percent of RGA origins not detectable by DSA were identified on CT. Origin detection rates were not significantly different for early/late arterial phases. Mean CNR was higher in the early arterial phase protocol (1.7 vs. 1.2, p < 0.001).ConclusionA 10-s delay arterial phase CT protocol does not significantly improve detection of small intra- and extrahepatic branches. RGA origin detection requires further optimization, whereas A4/MHA origin detection is adequate, with good inter-rater reproducibility. CT remains important for preprocedural planning, because it may reveal arterial anatomy not discernible on DSA.Key Points• An early arterial phase does not significantly improve RGA and A4/MHA origin detection.
• RGA origin detection (58–65 %) on CT is still suboptimal.
• 36 % of RGA origins undetectable on DSA can be identified on CT.
• A4/MHA origin detection (89–96 %) on CT is excellent.
• Inter-rater reproducibility is good for RGA and A4/MHA origin detection on CT.