Magnetic resonance imaging of the brain in chronic dialysis patients. Evaluation of high signal lesions in cerebral subcortical areas

This study was aimed to evaluate the incidence of cerebral subcortical high signal lesions (SHS) on T2 weighted images of Magnetic Resonance Imaging in chronic dialysis patients. The incidence of SHS was investigated in three clinically different groups of patients (196 divided into 3 age groups (20-40, 41-60, 61-83 years old). SHS were graded according to size and number. The incidence and severity of SHS increased with advancing age in all groups of patients and were higher in hypertensive and dialysis patients. Patchy confluent SHS were not identified in any patient younger than 60 years old in normal subjects and hypertensive patients. They were present in 9% in patients 41 to 60 years old of dialysis patients. In patients over than 61 years old, patchy confluent SHS were present in 1% of normal subjects, 11% of hypertensive patients, and 30% of dialysis patients. Duration, methods of dialysis therapy or previous history of hypertension in dialysis patients did not affect the incidence of SHS. SHS were mainly located in the territory of anterior, middle carebral and lenticulostriate arteries. In one autopsy case of chronic dialysis patient with severe SHS on magnetic resonance images, microscopic finding at pathological examination showed dilated perivascular space and increased water content in white matter. The results demonstrate a high incidence of severe SHS in chronic dialysis patients, and suggest that the SHS in dialysis patients appear to represent increased water content in perivascular brain tissue. (author)