345 . Cystic Hepatic Neoplasms: Complementary Roles of CT and Sonography Michael P. Federle1’2 Roy A. Filly1 Albert A. Moss1 Received April 28, 1 980; accepted after revi- sion September 26, 1980. ‘Department of Radiology, University of Califor- nia, San Francisco, CA 94143. 2Department of Radiology, San Francisco Gen- eral Hospital, 1 001 Potrero Ave. , San Francisco, CA 941 10. Address reprint requests to M. P. Federle. AJR 1 36:345-348, February 1981 o361-8o3x/81 /1362-0345 $00.00 © American Roentgen Ray Society Nine patients with cystic or necrotic hepatic neoplasms had findings on computed tomography (CT) that strongly suggested benign cystic disease of the liver. Sonography depicted the true morphology of these cystic lesions more clearly than CT, and the sonographic findings virtually excluded uncomplicated hepatic cyst as a diagnosis. Important observations were wall thickness, mural nodules, septations, and fluid-fluid levels. The potential danger in overreliance on CT attenuation values and the comple- mentary role of sonography and CT in such cases are stressed. Computed tomography (CT) and sonography are accurate methods of detect- ing focal hepatic lesions, including both primary and metastatic neoplasm [1 -7]. The typical CT and sonographic appearances of hepatic cysts, abscesses, and tumors have been described but only a few reports have considered the altered appearance of computed tomograms and sonograms when hepatic neoplasms undergo liquefaction necrosis. Such an appearance can be confused with benign cysts or abscesses [8, 9]. To our knowledge, there has been no report of primary hepatic neoplasms whose CT appearance closely simulated a benign cystic lesion. We studied several patients in whom CT findings strongly suggested benign cystic disease of the liver, but sonography provided valuable complementary information and virtually excluded uncomplicated hepatic cyst as a diagnosis. This experience prompted us to review all cases of hepatic neoplasms studied at this institution that had a cystic appearance on CT scanning. The potential danger in overreliance on CT attenuation values and the complementary role of sonography in further defining the nature of these lesions are stressed. Materials arid Methods Our series included seven patients with metastatic disease and two with primary neo- plasms in the liver. There were nine different primary tumors, including five carcinomas, two sarcomas, and two separate benign hepatic tumors. All nine patients were women, ages 23-63 years. There was histologic confirmation of the disease process in all cases, except for two patients in whom there was histologic confirmation of a primary neoplasm and strong clinical evidence of hepatic metastases, including progression of the disease process on subsequent examinations. All CT scans were obtained on a General Electric 7800 CT/T 4.8 sec scanner. Scans were generally obtained at 1 cm contiguous sections both before and after intravenous infusion of 300 ml 30% meglumine diatrizoate. In each case, the CT attenuation values of hepatic lesions were measured as a ‘‘ region of interest’ ‘ within an electronic cursor box. The CT data were not routinely manipulated to produce sagittal or coronal reconstructed images. Seven patients had sonographic examinations performed on commercially available analog or digital gray scale equipment. Depending on patient size, 1 9 mm, 2.25 or 3.5 MHz transducers with long internal focusing were used. Scans were generally performed at 1 cm intervals across the entire upper abdomen in both transverse and sagittal planes.