NEUROIMAGING FINDINGS IN PATIENTS ON IMMUNOSUPPRESSIVE THERAPY - EXPERIENCE WITH TACROLIMUS TOXICITY

OBJECTIVE. The purpose of this study is to describe the neuroimaging ( CT and MR imaging) findings in liver transplant patients who develop s evere neurologic side effects during immunosuppressive therapy with ta crolimus and to correlate these findings with clinical signs and tacro limus levels in blood. SUBJECTS AND METHODS. Brain CT and/or MR imagin g was performed on six patients who developed neurologic symptoms whil e receiving tacrolimus in the post-transplant period. All patients wer e evaluated by the neurology staff, and imaging studies were independe ntly interpreted by three neuroradiologists. Trough tacrolimus levels in blood were measured with the IMX immunoassay and were correlated wi th neurologic symptoms and imaging findings. RESULTS. Imaging abnormal ities were observed in five of six patients during the course of their neurologic illnesses. For each patient, neurologic symptoms began whe n the tacrolimus level in blood was at a peak, exceeding the therapeut ic limit in all but one case. In five patients, neurologic symptoms ev entually resolved after the tacrolimus dose was reduced or after the d rug was stopped. Multifocal low attenuation of white matter was the pr edominant finding seen on CT images, and matching hyperintense white m atter foci were observed on long-TR MR images. In three patients, clin ical recovery was accompanied by reversal of the white matter abnormal ities seen on CT and MR images. CONCLUSION. Immunosuppressive therapy with tacrolimus may produce neurologic side effects that are associate d with brain CT and MR imaging abnormalities. Resolution of symptoms a nd reversal of imaging findings occur when the tacrolimus dose is redu ced.