PATTERN OF CEREBRAL BLOOD-FLOW AND COGNITION IN PATIENTS UNDERGOING CHRONIC-HEMODIALYSIS TREATMENT

We studied 20 patients aged 46-69 years (mean 57 years) undergoing lon g-term haemodialysis (HD) and 20 age- and sex-matched controls with si ngle photon emission tomography (SPET) and Tc-99(m)-hexamethyl-propyle neamine-oxime to look for regional abnormalities in cerebral blood flo w (CBF) and their relation to cognitive dysfunction. Global hemispheri c tracer uptake relative to the cerebellum was similar in both groups, but regional over cerebellar activity was significantly reduced in th e frontal cortex (85.9 +/- 5.1 vs 90.4 +/- 5.3; P = 0.01) and thalamus (99.2 +/- 8.8 vs 104.9 +/- 8.4; P = 0.05) of the HD patients. Normali zation to whole-brain activity also showed the frontal cortex to be hy poactive in the HD patients, while tracer uptake was increased occipit ally. These regional differences were not explained by the presence of atrophy or cerebrovascular damage seen on brain magnetic resonance im aging. The HD patients scored significantly worse on cognitive tests s uch as the Mini Mental State Examination (23 +/- 4 vs 28 +/- 1; P < 0. 001) and Mattis Dementia Rating Scale (114 +/- 24 vs 143 +/- 1; P < 0. 001). Regional activity ratios did not correlate with cognitive test s cores, however. Our results indicate a disturbed pattern of CBF in HD patients, although regional SPET abnormalities did not correspond to t he severity of cognitive dysfunction.