Parkes Laura M, Rashid Waqar, Chard Declan T, Tofts Paul S
Department of Neuroinflammation, Institute of Neurology, University College London, London, UK.
Magn Reson Med. 2004 Apr;51(4):736-43. doi: 10.1002/mrm.20023.
Before meaningful conclusions can be drawn from clinical measures of cerebral blood perfusion, the precision of the measurement must be determined and set in the context of inter- and intrasubject sources of variability. This work establishes the reproducibility of perfusion measurements using the noninvasive MRI technique of continuous arterial spin labeling (CASL). Perfusion was measured in 34 healthy normal subjects. Intersubject variability was assessed, and age and gender contributions were estimated. Intersubject variation was found to be large, with up to 100% perfusion difference for subjects of the same age and gender. Repeated measurements in one subject showed that perfusion remains remarkably stable in the short term when compared with intersubject variation and the large capacity for perfusion change in the brain. A significant decrease in the ratio of gray-matter to white-matter perfusion was found with increasing age (0.79% per year (P < 0.0005)). This appears to be due mainly to a reduction in gray-matter perfusion, which was found to decrease by 0.45% per year (P = 0.04). Regional analysis suggested that the gray-matter age-related changes were predominantly localized in the frontal cortex. Whole-brain perfusion was 13% higher (P = 0.02) in females compared to males.
在从脑血流灌注的临床测量中得出有意义的结论之前，必须确定测量的精度，并将其置于个体间和个体内变异性的背景下。这项工作利用连续动脉自旋标记（CASL）的非侵入性MRI技术确定了灌注测量的可重复性。对34名健康正常受试者进行了灌注测量。评估了个体间变异性，并估计了年龄和性别的影响。发现个体间差异很大，年龄和性别相同的受试者灌注差异高达100%。对一名受试者的重复测量表明，与个体间差异和大脑灌注变化的巨大能力相比，灌注在短期内保持显著稳定。随着年龄的增长，灰质与白质灌注的比率显著下降（每年0.79%，P<0.0005）。这似乎主要是由于灰质灌注减少，发现每年减少0.45%（P=0.04）。区域分析表明，与年龄相关的灰质变化主要局限于额叶皮质。女性的全脑灌注比男性高13%（P=0.02）。
