Society of Gastrointestinal Radiologists Roscoe E. Miller Award. Monitoring hepatic cryosurgery with sonography.

The intraoperative sonographic appearance of frozen hepatic tumors and frozen normal liver was correlated with the histologic appearance of pathologic specimens from six patients. Frozen tissue was visualized as a hyperechoic rim with posterior acoustic shadowing. Normal liver that was frozen and then thawed appeared hypoechoic when compared with normal unfrozen liver. These findings allowed visualization of the extent of freezing in relation to tumor margins. Pathologically, frozen tumors showed definite evidence of necrosis. Normal liver tissue was extremely sensitive to cold and was completely necrotic after freezing. The sonographic appearance of frozen and thawed liver correlated precisely with the gross morphologic and histologic changes seen in the cryolesion. It appears that intraoperative sonography allows accurate monitoring of hepatic cryosurgery.