MRI STUDY OF HEPATIC-TUMORS FOLLOWING HIGH-INTENSITY FOCUSED ULTRASOUND SURGERY

High intensity, focused ultrasound has considerable potential as a non -invasive surgical technique, with applications which include the trea tment of benign prostatic hyperplasia and the elimination of metastati c disease in the liver. In this study, the use of MRI for treatment pl anning and subsequent monitoring of ultrasound therapy in the liver ha s been evaluated, In an experimental model both tumour bearing and nor mal liver lobes were treated invasively with high intensity focused be am ultrasound surgery. Subsequent changes in the tissue properties wer e investigated using MRI, in combination with the intravenous contrast agent, Gd-DTPA. The repair of ultrasound damaged tissue was followed until 8 weeks after treatment. The appearance of the MR images was com pared with histological sections prepared from parallel experiments. I maging and histology results showed excellent agreement, illustrating that MRI is well suited to the noninvasive observation of the effects of high intensity focused ultrasound therapy on tissue. Thus, as the c linical potential of ultrasound surgery is realized, MRI, together wit h the use of contrast agents, will be invaluable both in treatment pla nning and in monitoring the progress of a treated tumour.