Primary liver tumors in children: comparison of CT and MR imaging.

A prospective study was performed at two institutions to determine the role of magnetic resonance (MR) imaging in the evaluation of primary pediatric liver tumors. The study compared the usefulness of MR imaging and computed tomography (CT) in providing a correct diagnosis, assessing resectability, and determining tumor recurrence in 23 children with liver tumors. The information obtained with both modalities was correlated with surgical data. The results indicate that the accuracy of MR imaging in helping to differentiate benign from malignant lesions is high and identical to that of CT, but not good enough to obviate surgical diagnosis. While all five hepatocellular carcinomas were correctly diagnosed preoperatively with both modalities, neither CT nor MR imaging could help differentiate these carcinomas from aggressive hepatoblastoma or primary hepatic lymphoma. MR imaging helped correctly predict tumor resectability in all 18 children with malignant hepatic tumors; in one, exact tumor extension was misjudged with CT. Postoperative MR studies suggested tumor recurrence in three children who had unremarkable CT examinations. Second-look surgery showed recurrent tumor in two and fibrosis with chronic inflammation at the surgical margin in the third child.