Elevated global cerebral blood flow, oxygen extraction fraction and unchanged metabolic rate of oxygen in young adults with end-stage renal disease: an MRI study

To noninvasively assess global cerebral blood flow (CBF), oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) in young adults with end-stage renal disease (ESRD). Thirty-six patients and 38 healthy volunteers were included and took part in MR examinations, blood and neuropsychological tests. CBF and OEF were measured by phase-contrast and T2-relaxation-under-spin-tagging MRI techniques, respectively. CMRO2 was computed from CBF, OEF and hematocrit according to Fick's principle. Correlations were performed between MR measurements, blood biochemistry measurements and neuropsychological test scores. Compared with controls, ESRD patients had elevated CBF (72.9 +/- 12.5 vs. 63.8 +/- 8.5 ml min(-1) 100 g(-1), P < 0.001), elevated OEF (47.2 +/- 10.2 vs. 35.8 +/- 5.4 %, P < 0.001), but unaffected CMRO2 (199.5 +/- 36.4 vs. 193.8 +/- 28.6 mu mol O-2 min(-1) 100 g(-1), P = 0.879). Hematocrit negatively correlated with CBF (r = -0.640, P < 0.001) and OEF (r = -0.701, P < 0.001), but not with CMRO2. Altered neuropsychological test scores of ESRD patients were associated with OEF and CBF, but not with CMRO2. There were weak relationships between eGFR and hematocrit (r = 0.308, P = 0.068) or CBF (r = 0.318, P = 0.059). Our findings suggested that anaemic young adults with ESRD may afford higher CBF and OEF to maintain a normal CMRO2. Despite this compensatory process, however, cognitive function was still impaired and its severity was correlated with their CBF and OEF abnormality. aEuro cent Anaemic young adults with ESRD may afford higher CBF and OEF. aEuro cent Anaemic young adults with ESRD maintain a normal CMRO (2) . aEuro cent Cognitive function was still impaired in young ESRD adults. aEuro cent The severity of cognitive dysfunction correlated with CBF and OEF changes.