CT of the liver after cryotherapy of hepatic metastases: imaging findings.

Cryotherapy is the in situ destruction of abnormal tissue using subzero temperatures (Fig. 1). Recent studies have demonstrated the technical feasibility, safety, and effectiveness of hepatic cryotherapy in the treatment of liver tumors [1, 2]. Such treatment can be precisely focused on the tumor, thereby preserving surrounding normal tissue. In addition, because major vessels with flowing blood are protected from cryoablation, tumors adjacent to these vessels can be treated without sacrificing vasculature. Hepatic cryoablation is therefore particularly suitable for patients who do not qualify for surgical resection because of multiple metastases involving both lobes of the liver, or because of lesions close to major blood vessels. After the procedure, CT during arterioportography is of little value in distinguishing cryolesion from malignant tumor (Fig. 2), and CT with IV contrast enhancement is recommended for follow-up. It is important to distinguish CT findings of successful and unsuccessful treatment, treatment complications such as abscess and cholestasis, and recurrent tumor. The purpose of this essay is to illustrate the findings on CT with IV contrast enhancement in various situations, emphasizing features that are useful in making accurate differential diagnosis.