Sonographic appearances of small hepatic nodules without tumor stain on contrast-enhanced computed tomography and angiography

PURPOSE: We report the sonographic appearances and pathologic findings for hepatic nodules 2 cm or smaller that were detected by sonography but that did not produce a tumor stain on constrast-enhanced helical CT or digital subtraction angiography. METHODS: Sixty-six nodules 2 cm or less were found by sonography in 39 patients. Sonographically guided needle biopsies were done on all lesions. RESULTS: Twenty-seven nodules were benign nodules, 9 were borderline lesions, and 30 were hepatocellular carcinomas. Benign nodules were significantly smaller than hepatocellular carcinomas (mean size, 1.0 cm versus 1.4 cm, respectively; p <0.00001). Nodules 1 cm or smaller were more likely to be diagnosed as benign nodules (68%) than as either of the other types (32%; p = 0.01). A significantly greater percentage of hepatocellular carcinomas showed a heterogeneous pattern (64%) on sonography compared with benign nodules (25%) and borderline lesions (11%; p = 0.04). In nodules 1 cm or smaller, a homogeneous pattern (68%) was more common than a heterogeneous pattern (32%; p = 0.01). CONCLUSIONS: The nature of small hepatic nodules cannot be determined with sonography. Thus, biopsy remains the only technique for obtaining a definitive diagnosis.