[Clinical study of transcatheter arterial chemoembolization plus radiofrequency ablation in hepatocellular carcinoma by magnetic resonance imaging and functional diffusion-weighted imaging].

OBJECTIVE: To evaluate the apparent diffusion coefficient (ADC) value features of the lesions after transcatheter arterial chemoembolization (TACE) plus radiofrequency ablation in hepatocellular carcinoma (HCC) with 3.0T magnetic resonance imaging (MRI) and diffusion-weight imaging (DWI) and analyze the value of 3.0T DWI in detecting the pathological lesion features of post-TACE plus radiofrequency ablation in HCC. METHODS: Twenty-eight HCC patients were enrolled to receive TACE firstly. Then all viable tumors around the lesions underwent radiofrequency ablation. At 1-4 months after radiofrequency ablation, 3.0T MRI and DWI (b = 600 sec/mm(2)) were performed to measure the ADC values of different lesions of post-TACE plus radiofrequency ablation. The features of MRI and ADC values of different lesions, the difference of contrast enhancement sequence and DWI in evaluating the lesions of post-TACE plus radiofrequency ablation were analyzed. RESULTS: Viable tumors occurred in 14 of 28 HCC patients after TACE plus radiofrequency ablation. The ADC values of necrotic tissues with lipiodol, necrotic tissues without lipiodol, viable tumors and normal liver tissues were 1.905 ± 0.487, 0.726 ± 0.116, 1.449 ± 0.054 and 1.777 ± 0.094 (10(-3) mm(2)/sec) respectively. There was no significant difference of ADC values between necrotic tissues with lipiodol and normal tissues (P = 0.115). But there were significant differences of ADC values among necrotic tissues with lipiodol, necrotic tissues without lipiodol and viable tumors (P < 0.05). The viable tumor tissues after TACE plus radiofrequency ablation appeared as nodular lesions with slightly heightened signal intensities around the necrotic tissues, the lesions with heterogeneous enhancement during arterial phase, portal vein phase and parenchymal phase. Necrotic tissues without lipiodol occurred outside necrotic tissues without lipiodol, around normal liver tissues, with low signal intensities on T2WI, without enhancement during arterial phase, portal vein phase and parenchymal phase. There were no significant difference between contrast enhancement and DWI sequence in detecting viable tumors after TACE plus radiofrequency ablation (P > 0.05). CONCLUSION: The ADC values of 3.0T MR DWI may be used to distinguish the viable residue or recurrent tumor tissues, necrotic tissues in HCC after TACE plus radiofrequency ablation.