Estimation of intersubject variability of cerebral blood flow measurements using MRI and positron emission tomography

Abstract

Purpose: To investigate the within and between subject variability of quantitative cerebral blood flow (CBF) measurements in normal subjects using various MRI techniques and positron emission tomography (PET). Materials and Methods:Repeated CBF measurements were performed in 17 healthy, young subjects using three different MRI techniques: arterial spin labeling (ASL), dynamic contrast enhanced T1 weighted perfusion MRI (DCE) and phase contrast mapping (PCM). All MRI measurements were performed within the same session. In 10 of the subjects repeated CBF measurements by 15 O labeled water PET had recently been performed. A mixed linear model was used to estimate between subject (CV betw ) and within subject (CV with ) coefficients of variation.Results: Mean global CBF, CV betw and CV with using each of the four methods were for PCM 65.2 mL/100 g/min, 17.4% and 7.4%, for ASL 37.1 mL/100 g/min, 16.2% and 4.8%, for DCE 43.0 mL/100 g/min, 20.0%, 15.1% and for PET 41.9 mL/100 g/min, 16.5% and 11.9%, respectively. Only for DCE and PCM a significant positive correlation between measurements was demonstrated.Conclusion: These findings confirm large between subject variability in CBF measurements, but suggest also that in healthy subjects a subject-method interaction is a possible source of between subject variability and of method differences.

Sources of Variability of Resting Cerebral Blood Flow in Healthy Subjects: A Study Using133Xe SPECT Measurements

“…23,34 Metabolic Basis of Between-Subject Variability Previous studies show a very similar between-subject variability in healthy young subjects with between-subject coefficient of variation of 16% using the Kety Schmidt technique 1 and of 15% to 20% using various magnetic resonance imaging and positron emission tomography methods. 4 Relative between-subject variability in the present study was B13%. These figures are very similar to the coefficient of variation of 13% of both CMRO 2 and neuron density reported in brains of healthy subjects.…”

“…The model is explained in more details in a previous publication. 4 Within-subject variability (or test-retest variability) includes both random method imprecision and true within-subject variability, whereas between-subject variability reflects the true variability of CBF and systematic (or subject-specific) errors. These two variance components were entered as random effects in the model.…”

Accuracy of Parenchymal Cerebral Blood Flow Measurements Using Pseudocontinuous Arterial Spin-Labeling in Healthy Volunteers

“…Other studies have found moderate to good correlations (r ϭ 0.4 -0.8) between pseudocontinuous ASL and PET imaging for pCBF measurements. 4,27,28 On the contrary, Henriksen et al 29 showed a large underestimation of ASLbased pCBF (75%) compared with the estimation by PCMRI and no correlation between the 2 methods. One explanation for this result might be that they used a model-free pulsed-ASL method.…”

Alterations in Cerebral Oxygen Metabolism after Traumatic Brain Injury in Children

“…51 The average CBF in the control cohort is somewhat higher than the CBF values reported in young adults using arterial spin labeling. 52 Cerebral blood flow displayed significant intersubject variability, with even the healthy controls spanning a range of almost 30 to 60 mL per minute per 100 g. Since the outcome of interest is the difference between the two patient samples (TBI and control subjects), we did not conduct paired analysis. Future studies will address this limitation to study individual patient changes in metabolism over time after TBI.…”