Hypervascular hepatic metastases: CT evaluation.

Recent reports have indicated that non-contrast material-enhanced scans are of less value than urographic contrast material-enhanced studies in the computed tomographic (CT) evaluation of hepatic metastases. The authors retrospectively reviewed the CT scans of 28 patients with hypervascular liver metastases to determine whether these metastases were more likely to become isodense with the liver after contrast material enhancement, thus necessitating the performance of non-contrast-enhanced scanning. Non-contrast-enhanced and contrast-enhanced incremental dynamic scanning was performed in patients with proved liver metastases from carcinoid tumors (13 patients), islet cell neoplasms (ten patients), pheochromocytomas (four patients), or renal cell carcinoma (one patient). Eleven of the 28 patients (39%) had metastases with non-contrast liver-to-lesion attenuation differences greater than 15 HU. These metastases subsequently became isodense or nearly isodense on contrast-enhanced scans. The authors conclude that non-contrast-enhanced CT scanning should be performed in patients with suspected liver metastases from tumors that are usually hypervascular.