Smith, LA;
Melbourne, A;
Owen, D;
Cardoso, MJ;
Sudre, CH;
Tillin, T;
Sokolska, M;
... Jäger, HR; + view all
(2019)
Cortical cerebral blood flow in ageing: effects of haematocrit, sex, ethnicity and diabetes.
European Radiology
, 29
(10)
5549 -5558.
10.1007/s00330-019-06096-w.
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Hughes_Cortical cerebral blood flow in ageing effects of haematocrit, sex, ethnicity and diabetes.pdf - Published Version Download (2MB) | Preview |
Abstract
Objectives: Cerebral blood flow (CBF) estimates from arterial spin labelling (ASL) show unexplained variability in older populations. We studied the impact of variation of haematocrit (Hct) on CBF estimates in a tri-ethnic elderly population. / Materials and methods: Approval for the study was obtained from the Fulham Research Ethics Committee and participants gave written informed consent. Pseudo-continuous arterial spin labelling was performed on 493 subjects (age 55–90) from a tri-ethnic community-based cohort recruited in London. CBF was estimated using a simplified Buxton equation, with and without correction for Hct measured from blood samples. Differences in perfusion were compared, stratified by sex, ethnicity and diabetes. Results of Student’s t tests were reported with effect size. / Results: Hct adjustment decreased CBF estimates in all categories except white European men. The decrease for women was 2.7 (3.0, 2.4) mL/100 g/min) (mean (95% confidence interval (CI)), p < 0.001 d = 0.38. The effect size differed by ethnicity with estimated mean perfusion in South Asian and African Caribbean women found to be lower by 3.0 (3.6, 2.5) mL/100 g/min, p < 0.001 d = 0.56 and 3.1 (3.6, 2.5) mL/100 g/min), p < 0.001 d = 0.48, respectively. Estimates of perfusion in subjects with diabetes decreased by 1.8 (2.3, 1.4) mL/100 g/min, p < 0.001 d = 0.23) following Hct correction. Correction for individual Hct altered sample frequency distributions of CBF values, especially in women of non-European ethnicity. / Conclusion: ASL-derived CBF values in women, non-European ethnicities and individuals with diabetes are overestimated if calculations are not appropriately adjusted for individual Hct.
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