Focal hepatic lymphoma: magnetic resonance demonstration using current techniques including gadolinium enhancement.

This study demonstrates the appearance of focal hepatic lymphoma using current magnetic resonance techniques including gadolinium enhancement. Fifteen patients with hepatic lymphoma were imaged at 1.5T. T1-weighted, T2-weighted, immediate, and 5-10-min delayed T1-weighted spoiled gradient echo images were acquired in all patients. Determination was made of lesion size, number, morphology, and signal intensity of lesions on all sequences. Seven patients had solitary lesions and 8 patients had multiple lesions. Focal lesions of hepatic lymphoma ranged in size from 5 mm to 15 cm. They were well defined masses with mild to moderate low signal intensity relative to liver on T1-weighted images. Lymphoma lesions in 6 patients were moderately high in signal intensity on T2-weighted images compared with liver (Type I lesions), and enhancement of lesions was intense on early post-gadolinium images in 5 of these patients. Lymphoma lesions in 6 patients were mildly hypointense to mildly hyperintense on T2-weighted images compared to liver (Type II lesions), and lesions in 5 of these patients enhanced minimally on the early post-gadolinium spoiled gradient echo images. The remaining 3 patients had received chemotherapy before the magnetic resonance examination, and the imaging findings varied reflecting presumed differences in treatment responses. Transient ill defined perilesional enhancement on immediate post-gadolinium spoiled gradient echo images was observed in 9 patients including patients with either type of lesion. Focal lesions of hepatic lymphoma are usually low in signal intensity on T1-weighted images but have variable signal intensity on T2-weighted images. In general, lesions that are mildly hypointense to minimally hyperintense in signal intensity on T2-weighted images enhance minimally, and lesions moderately high in signal intensity of T2-weighted images enhance intensely. Transient increased perilesional enhancement is common.