Watershed imaging features and clinical vascular injury in cyclosporin A neurotoxicity

Purpose: The purpose of our study was to assess whether the imaging and clinical features of cyclosporin A (CsA) neurotoxicity support a vascular ''watershed'' cause for the brain lesions observed. Method: Fourteen patients receiving CsA after allogeneic bone marrow transplantation or with marrow aplastic disorders developed neurotoxicity and MR or CT imaging abnormalities. The locations of brain lesions were analyzed, and clinical features, in particular bone marrow transplant thrombotic microangiopathy (BMT-TM), were assessed. Results: Sixty-six lesions had consistent locations in watershed zones between major cerebral vessels or their main branches, including the parietal area (19), occipital poles (18), frontoparietal junction (15), inferior temporooccipital junction (10), and cerebellum (3). BMT-TM was identified in 10 of 10 marrow transplant patients studied. Conclusion: Vascular injury, suggested from watershed location and BMT-TM, likely establishes the location of the brain lesions in CsA neurotoxicity. Secondary toxicity in these vulnerable regions may cause the white matter lesions.