RESUMO
PURPOSE: To evaluate accuracy of virtual parenchymal perfusion (VPP) algorithm developed for targeting liver cancer during intra-arterial therapy (IAT) using cone-beam CT guidance. MATERIALS AND METHODS: VPP was retrospectively applied to 15 patients who underwent IAT for liver cancer. Virtual territory (VT) was estimated after positioning a virtual injection point on nonselective dual-phase (DP) cone-beam CT images acquired during hepatic arteriography at the same position chosen for selective treatment. Targeted territory (TT) was used as the gold standard and was defined by parenchymal phase enhancement of selective DP cone-beam CT performed before treatment start. Qualitative evaluation of anatomic conformity between VT and TT was performed using a 3-rank scale (poor, acceptable, excellent) by 3 double-blinded readers. VT and TT were also quantitatively compared using spatial overlap-based (Dice similarity coefficient [DSC], sensitivity, and positive predictive value), distance-based (mean surface distance [MSD]), and volume-based (absolute volume error and correlation between pairwise volumes) metrics. Interreader agreement was evaluated for the 2 evaluation methods. RESULTS: Eighteen DP cone-beam CT scans were performed. Qualitative evaluation showed excellent overlap between VT and TT in 88.9%-94.4%, depending on the readers. DSC was 0.78 ± 0.1, sensitivity was 80%, positive predictive value was 83%, and MSD was 5.1 mm ± 2.4. Absolute volume error was 15%, and R2 Pearson correlation factor was 0.99. Interreader agreement was good for both qualitative and quantitative evaluations. CONCLUSIONS: VPP algorithm is accurate and reliable in identification of liver arterial territories during IAT using cone-beam CT guidance.
