Value of MR Imaging after CT in Patients with Focal Hepatic Lesion

PURPOSE: To determine the usefulness of magnetic resonance imaging (MRI) after computed tomography (CT) inpatients with focal hepatic lesion. MATERIALS AND METHODS: We evaluated 100 patients with 103 focal hepaticlesions. The diagnosis of each lesion was made pathologically (n=19), or radiologically and clinically (n=84), andthe findings were as follows: he-mangioma (n=53), hepatocellular carcinoma (n=17), metastasis (n=10), cyst (n=5),regenerative nodule (n=3), and adenomatous hyperplasia (n=3). The patients underwent conventional CT (n=25),two-phase spi-ral CT (n=17) or three-phase spiral CT (n=61). MRI was performed using conventional T1- andT2-weighted imaging and dynamic contrast enhancement. The value of MRI after CT was assigned to one of fourgrades, according to the consensus of three radiologists: grade I (decisive), grade II (helpful), grade III (notadditional), or grade IV (confused). RESULTS: The outcome of MRI of 103 lesions was grade I in 14 cases(14%), IIin 34 (33%), III in 49 (48%), and IV in 6 (6%). MRI was not helpful (grade III or IV) in 40% (10/25), 47% (8/17),and 61%(31/61) of lesions after conventional, two-phase spiral, and three-phase spiral CT, respectively. Grade IIIor IV lesions were present in 45% of hemangiomas (24/53), 59% of hepatocellular carcinomas (10/17), and 80% ofcases in which metastasis had occurred(8/10). CONCLUSION: MRI after CT in patients with focal hepatic lesion washelpful in less than half of all cases. It was particularly valuable for patients who did not undergo three-phasespiral CT and in whom hemangioma was suspected.