Cognitive impairment in patients with renal failure is associated with multiple-infarct dementia

Purpose: Patients undergoing long-term renal replacement therapy (such as d ialysis) have an increased risk for significant cognitive impairment, which may result in memory problems and subsequently missed attendance at dialys is. The aim of this study was to try to identify any abnormalities of cereb ral perfusion that could explain a patient's cognitive impairment and to de termine if the pattern of these abnormalities would suggest a cause. Materials and Methods: 17 patients (13 men; mean age, 60 years; age range, 29-74 years) in end-stage renal failure or on dialysis had SPECT imaging 10 minutes after injection of 550 MBq (15 mCi) Tc-99m HMPAO. Two of the patie nts had a history of previous stroke. Other risk factors for stroke were no ted in most of the patients (hypertension in 10 patients, smoking or former smoking in 10 patients, and cardiac atherosclerosis in 7 patients). In all patients, attenuation correction was applied and the images were reconstru cted into three sets of orthogonal slices. Activity in the frontal and temp oral lobes was compared by quantification against the ipsilateral and contr alateral cerebellum. Results: Discrete cortical defects consistent with infarcts were seen in 14 patients. The mean right and left frontal-to-cerebellar ratio was 0.837 (S D, 0.09) and 0.837 (SD, 0.08), respectively. This was not significantly dif ferent from the right and left temporal-to-cerebellar ratios of 0.843 (SD, 0.07) and 0.848 (SD, 0.07), respectively. Both were within normally accepte d ranges. Conclusions: Patients in end-stage renal failure who also had cognitive imp airment appear to have a high number of cortical defects consistent with in farcts (suggesting a multiple-infarct type of dementia). There was no evide nce of Alzheimer-type dementia.