Objective: The objective of our study was to investigate the diagnostic performance of C-arm CT and its value to predict response of hepatocellular carcinoma (HCC) to trans-catheter arterial chemoembolization (TACE) compared with gadoxetic acid-enhanced MRI.
Materials and methods: Sixty-eight patients with HCCs (n=167; 145>1 cm, 22≤1 cm) underwent both C-arm CT immediately before TACE and gadoxetic acid-enhanced MRI within 2 weeks before TACE. Two radiologists rated the possibility of HCC using a 5-point confidence scale focused on the degree of arterial enhancement and the shape of the lesion seen on C-arm CT. They also graded the possibility of HCC on MRI based on the signal intensities on T1- and T2-weighted images, arterial enhancement, and hypointensity on both the late phase and the hepatobiliary phase. We also measured the apparent diffusion coefficient value. The diagnostic accuracy was evaluated using the alternative free-response receiver operating characteristic curve method. A multivariate logistic regression analysis was performed between the good-response and nonresponse HCCs for TACE.
Results: The diagnostic accuracy of MRI was greater than that of C-arm CT (0.890 vs 0.681, respectively; p<0.001). However, in small HCCs (≤1 cm), C-arm CT showed a higher sensitivity than MRI (90.9% vs 70.5%, respectively; p=0.023) and a lower positive predictive value than MRI (40.8% vs 57.4%, p=0.073). Well-defined strong arterial enhancement on C-arm CT (odds ratio=8.08, p=0.05) was statistically significant for predicting therapeutic response of HCC to TACE.
Conclusion: C-arm CT showed greater sensitivity than gadoxetic acid-enhanced MRI in depicting small HCCs (≤1 cm). Furthermore, well-defined strong arterial enhancement on C-arm CT can be used to predict therapeutic response of HCC to TACE.