Dynamic susceptibility contrast enhanced MRI in reversible posterior leukoencephalopathy syndrome associated with haemolytic uraemic syndrome

We describe a case of reversible posterior leukoencephalopathy associated w ith haemolytic uraemic syndrome. Following remission confirmed on MRI, the patient relapsed several months later. Neuroimaging findings on conventiona l MRI and FLAIR sequences and dynamic susceptibility contrast enhanced MRI are described. White matter abnormalities may be shown on CT or MRI in this syndrome. However, dynamic susceptibility contrast enhanced MRI showed far more extensive abnormality within the brain. In addition, phase contrast a ngiographic measurement of flow in the carotid and basilar arteries indicat ed a significant elevation of cerebral blood flow, suggesting a decrease in global cerebrovascular resistance. These observations support existing the ories that the disorder is manifested by autoregulatory disturbance in smal l cerebral vessels. Our findings suggest that this abnormality is far more extensive than is demonstrated on T-2 weighted MR images and that it is ass ociated with global abnormality of cerebrovascular autoregulation.