Purpose: To evaluate the frequency and clinical importance of small (<or=2 cm) early-enhancing hepatic lesions in cirrhotic liver disease with serial multiphasic contrast material-enhanced dynamic magnetic resonance (MR) imaging.
Materials and methods: The study population included 208 patients with cirrhosis (n = 162) or chronic hepatitis (n = 46) who underwent dynamic contrast-enhanced MR imaging at least twice during the clinical course, with at least a 12-month interval between the initial and latest MR examinations. Initial images were evaluated for the presence and shape of small (<or=2 cm) early-enhancing hepatic lesions at arterial-phase contrast-enhanced MR imaging. If a small early- enhancing lesion was seen on the initial image, the latest follow-up image was reviewed to assess the serial changes in the features of a specific lesion.
Results: One hundred fifty-eight small early-enhancing lesions were detected in 75 (36%) of the 208 patients on the initial MR images. Of those 158 lesions, 104 were round or oval, 30 wedge-shaped, 18 geographic (irregularly shaped), and six triangular. Among the 104 round or oval lesions, 54 (52%) disappeared or decreased in size on the latest MR images and were considered definite pseudolesions. Twenty-nine (28%) of the 104 round or oval lesions were classified as hepatocellular carcinoma (HCC) on the basis of their interval growth or pathologic confirmation. The remaining 21 (20%) lesions were stable in size and appearance and considered probable pseudolesions. For the other three shapes, 73% of wedge-shaped, 78% of geographic, and 67% of triangular lesions disappeared or decreased in size.
Conclusion: Small early-enhancing hepatic lesions in patients with cirrhosis usually showed no interval growth or disappeared during serial contrast-enhanced dynamic MR imaging. Even though these lesions are round or oval, they may more frequently be pseudolesions than HCCs.