[Value of computed tomography and magnetic resonance imaging in diagnosis and differential diagnosis of small hepatocellular carcinoma].

OBJECTIVE: To analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of small hepatocellular carcinoma to improve the accuracy in the diagnosis.

METHODS: This retrospective analysis involved 41 patients with small hepatocellular carcinoma cases confirmed by pathological examination of the biopsy samples or follow-up. These patients were assessed for CT and MRI findings including lesion size, density or signal intensity, enhancement patterns, and presence of tumor capsules.

RESULTS: On unenhanced CT images, small hepatocellular carcinomas were displayed mainly as low-density masses, and the majority of tumors presented with low signal intensity on T1-weighted unenhanced MR images with increased signal intensity on T2-weighted images in comparison with the surrounding liver parenchyma. Most of tumors showed intense enhancement during the arterial phase (CT in 15 cases and MRI in 13 cases), but some appeared isointense to the liver parenchyma (CT in 4 cases and MRI in 4 cases). In portal and delayed phases, the tumors typically had lower signal intensity than that of the surrounding liver tissues (CT in 25 cases and MRI in 12 cases) with enhancement of the tumor capsules (13 cases).

CONCLUSION: Dynamic enhanced scanning can be more informative of the pathology and blood supply of small hepatocellular carcinoma. Early and late arterial phase imaging may help in detecting the small lesions and in making differential diagnosis.