C-Arm CT for Assessing Initial Failure of Iodized Oil Accumulation in Chemoembolization of Hepatocellular Carcinoma

OBJECTIVE. The purpose of our study was to assess the feasibility of using C-arm CT to detect incomplete accumulation of iodized oil in hepatocellular carcinoma immediately after transarterial chemoembolization (TACE). MATERIALS AND METHODS. This retrospective study included 80 hepatocellular carcinoma lesions in 55 patients (41 men and 14 women; mean age, 69.2 years; mean tumor size, 18.1 mm [range, 5-55 mm]) who underwent TACE with a flat-detector C-arm angiographic system. C-arm CT images were acquired at the end of each session, and unenhanced MDCT images were obtained 7 days later. Two independent observers scored both sets of images, using a predefined detection scale for incomplete iodized oil accumulation. The accuracy for predicting residual lesions was compared using the area under the receiver-operating characteristic curve (A(z)). Contrast-enhanced CT findings obtained 1 month after TACE served as reference standards. RESULTS. Viable lesions were observed in 18 of the 80 study lesions by contrast-enhanced CT. The accuracy of the C-arm CT (A(z) = 0.816) was not significantly different (p = 0.449) from that of the MDCT (A(z) = 0.841). Sensitivity, specificity, and positive and negative predictive values for C-arm CT (80.5%, 74.2%, 47.5%, and 92.9%, respectively) and MDCT (86.1%, 75.0%, 50.0%, and 94.9%, respectively) did not differ significantly. CONCLUSION. C-arm CT is nearly equivalent to MDCT for detecting incomplete iodized oil accumulation after TACE, suggesting that the immediate assessment of iodized oil accumulation with C-arm CT without the need to perform follow-up unenhanced MDCT is likely feasible.