Dual-energy CT to detect recurrent HCC after TACE: initial experience of color-coded iodine CT imaging

Abstract

Objectives: To evaluate the feasibility of diagnosing recurrence of HCC after TACE color-coded iodine CT (CICT) based on arterial phase scans obtained by a dual-energy CT (DECT) scanner.

Methods: A CICT scan was acquired from an iodine map after applying material decomposition of the liver tissue and setting a threshold attenuation level for viable tumors. Two radiologists reviewed both conventional and CICT sets in 31 patients who had a history of TACE for HCC. The performances in detecting local tumor progression (LTP) were evaluated by alternative free-response receiver operating characteristics. The rate of uncertain diagnosis and interobserver agreement of the diagnosis were explored. Additionally, the reading time and radiation dose were also investigated.

Results: The mean figures of merit of the conventional and CICT sets for LTP were 0.818 and 0.847, respectively (p=0.459). The rate of uncertain diagnosis was significantly decreased in CICT sets (34.5% vs. 0%), and interobserver agreement was improved (k=0.527 vs. 0.718). On the CICT set, mean reading time was reduced by 49s and mean radiation dose was also decreased by 18.3% when replacing the non-contrast CT with CICT.

Conclusions: CICT is comparable to conventional liver CT protocol in demonstrating viable HCCs, while it allows a reduction in radiation dose.