BACKGROUND AND PURPOSE:Whether ADC value predicts the therapy response and outcomes of primary central system lymphoma remains controversial.This study assessed the minimum ADC correlated with treatment response in patients with primary central nervous system lymphoma undergoing methotrexate-based chemotherapy.MATERIALS AND METHODS:Thirty-five patients with primary central nervous system lymphoma underwent conventional MR imaging and DWI before chemotherapy and after 1 and 5 cycles of chemotherapy.