Diffusion-weighted MR imaging for liver cancer follow-up after transcatheter arterial chemoembolization

Objective: To investigate prospectively the apparent diffusion coefficient (ADC)in evaluating the capability of diffusion-weighted imaging (DWI) technique for detecting viable tumor tissue after transarterial chemoembolization (TACE) of liver cancer. Methods: Institutional review board approval was obtained, and all patients were provided with informed consent. DWI, enhanced CT and DSA examinations were performed in 16 patients with liver cancer after TACE. Qualitative evaluations of the capability for detecting the remaining or recurrent viable tumor with DWI were performed by comparing enhanced-CT and DSA. ADCs and maximum CT enhancement value(HU) were measured(in 14 of the 16 patients)for lesions after TACE. And their relationships were investigated by comprehension correlative analysis. Results: Liver cancer after TACE presented variable signal intensities on DWI. The homogeneous accumulation of iodized oil observed on CT in 2 of 16 patients with liver cancer after TACE showed no tumor stain observed on DSA but with corresponding homogeneous hypointensity on DWI. The partial defects shown in accumulation of iodized oil in 2 of 16 patients represented the tumor stain on DSA corresponding to hyperintensities on DWI. None or faint accumulation of iodized oil areas in 12 of all patients, showed striking tumor stains corresponding to hyperintensities on DWI, and tumor necrosis had none or sight tumor stain on DSA, corresponding to hypointensities on DWI. A correlation between ADCs and maximum CT enhancement value (HU) of lesions after TACE was found (r=-0.76490, <0.05). Conclusion: Diffusion MRI is an useful method for detecting tumor remnant or recurrence of liver cancer after TACE, and can be used for the follow-up. (authors)