Well-differentiated hepatocellular carcinoma: findings of US, CT, and MR imaging

Background: To elucidate the imaging characteristics of well-differentiated hepatocellular carcinomas (HCCs) on ultrasonography (US), computed tomogra phy (CT), and magnetic resonance (MR) imaging, Methods: Ultrasonograms, CTs, and MR images of 18 histopathologically prove n well-differentiated HCCs in 15 patients were reviewed. The findings of th ese images were correlated with histopathologic findings. Results: On US, seven tumors were depicted as a hyperechoic area and eight as a hypoechoic area. Three tumors were not visualized. On precontrast CT, four tumors were depicted as a low-density area, but 14 were nor visualized , On conventional contrast-enhanced CT, 12 tumors were depicted as a low-de nsity area but six were not visualized. On T1-weighted MR images, 10 tumors had high signal intensity and two had low signal intensity. Six tumors wer e not visualized. On T2-weighted MR images, five tumors had high signal int ensity and two had low signal intensity. Eleven tumors were not visualized. Tumors with fatty change and/or clear cell formation were frequently hyper echoic on US and hyperintense on T1-weighted MR images. Conclusions: Well-differentiated HCCs show different findings on US, CT, an d MR imaging. Therefore, reliable diagnosis of well-differentiated HCCs by these imaging techniques may be difficult.