MRI features of primary central nervous system lymphomas

Objective To observe MRI features of primary central nervous system lymphoma(PCNSL).Methods MRI findings of 26 cases with pathologically-proved PCNSI.were analyzed retrospeetively,emphasizing on the location,signal feature,contrast-enhanced type,perilesional edema,ependymal seeding,and infiltration of corpus callosum.Results A- mong the 26 cases(7 of them were solitary,the others were multiple),16 of them were located in the corpus callosum,basal ganglia and periventricule region,7 cases in encephalic surface and white-gray matter junction region,and 3 in intraventri- cule,respectively,whereas ependymal seeding lesions could be observed in 13 cases.Typical"butterfly sign"was found in cases with involvement of corpus callosum.Solid portion displayed as hypointensity on T1WI and iso-hyperintensity on T2WI,and hyperintensity on DWI with low ADC.After the infusion of paramagnetic contrast material,intense homogene- ous enhancement in the solid portion was detected in 24 cases,while ring enhancement in the rest 2 cases.Intraventricular and ependymal seeding lesions appeared as homogeneous masses,enhanced intensively and homogeneously.Perilesional ede ma depended on the locations.There was mild to moderate edema in the corpus callosum,basal ganglia and periventricule re- gion lesions,while moderate to high in the encephalie surface and white-gray matter junction region lesions.Conclusion Most PCNSL have typical MRI appearance that will he helpful for the preoperative diagnosis.