CT and MR imaging of hepatocellular carcinoma after microwave coagulation therapy. Evaluation of changes in the surrounding hepatic parenchyma and local recurrence

The changes in the surrounding hepatic parenchyma and local recurrence in the 68 lesions of hepatocellular carcinoma after microwave coagulation therapy (MCT) were investigated by CT and MRI. On CT and/or MRI obtained within 30 days after MCT, the surrounding hepatic parenchyma demonstrated wedge-shaped enhancement in 21 lesions while ring enhancement in 40. On follow-up imaging, such enhancement disappeared in 12 and 26 lesions respectively, and decreased in the remaining lesions. Local recurrence was noted in 32 lesions. Twenty-seven of them were detected by CT and/or MRI, and the shapes were nodular in 17 lesions, wedge-shaped in 4 and linear in 6. Regardless of the vascularity of the tumor before the treatment, all the recurrent tumors were enhanced. The wedge-shaped and linear recurrence corresponded to the peripheral enhancement in the surrounding hepatic parenchyma. However, it was possible to differentiate them because the enhancement of recurrent tumors appeared or increased during the course of observation. It was considered important to perform follow-up CT and/or MRI regularly to detect recurrence after MCT. (author)