Initial and follow-up MR imaging findings in AIDS-related progressive multifocal leukoencephalopathy treated with highly active antiretroviral therapy

BACKGROUND AND PURPOSE: Recent studies have Shown the beneficial effect of highly active antiretroviral therapy (HAART) in AIDS-related progressive mu ltifocal leukoencephalopathy (PML). The purpose of our study was to evaluat e the initial and follow-up imaging findings and survival in patients with PML who were treated with HAART. METHODS: The clinical course and MR imaging findings on initial and follow- up MR studies in four consecutive AIDS patients with PML who were treated w ith HAART are described. RESULTS: Two patients were short-term survivors and died after 3 months, Tw o patients are still alive, with a survival time of 22 and 43 months, respe ctively, On initial MR studies, more extensive white matter changes were se en in the short-term survivors. Development of a mass effect and temporary enhancement (in one patient) was observed in two HAART responders on follow -up MR studies, Increased hypointensity on T1-weighted images with concomit ant low signal on fluid-attenuated inversion-recovery fast spin-echo (FLAIR -FSE) images was seen in two responders, representing leukomalacia, Atrophi c changes of the involved areas of the brain, consistent with burnt out PML lesions, were seen in two long-term survivors, In the short-term survivors , increased hypointensity was present on TI-weighted images with increased high signal on FLAIR-FSE images, representing progressive destructive disea se, CONCLUSION: Our results suggest that a clinical and radiologic response can be seen in some patients with AIDS-associated PML on HAART while in others there may be no beneficial response. Development of a mass effect and temp orary enhancement on MR images in the early phase of treatment might repres ent positive predictive factors for prolonged survival.