Multidelay arterial spin-labeled perfusion magnetic resonance imaging in healthy individuals: A single-center experience

Purpose: To explore the optimal postlabeling delay (PLD) of arterial spin labeling (ASL) in different age groups and the correlation between cerebral blood flow (CBF) and age in adults. Materials and Methods: Eighty-four healthy adults (20-80 years) were divided into three groups (youth group, middle-aged group, elderly group) and underwent conventional MRI and three-dimensional arterial spin labeling (3D-ASL) perfusion scanning. Multi-phase PLDs (1025,1525,2525, 3025ms) were used in each age group. Statistical parametric mapping (SPM) was used to analyze the data and to extract the CBF of predefined regions of interest (ROI) including whole brain gray matter, frontal lobe, parietal lobe, temporal lobe, occipital lobe and limbic lobe. Results: The CBF of shorter PLDs (1025,1525ms) were higher in the youth group, and the CBF were higher with longer PLDs (2525,3025ms) in the middle-aged and elderly group. In addition, the standard deviation of CBF was lower with longer PLD in all age groups. The CBF of all ROIs had negative correlation with age (r=-0.440, P < 0.001; -0.425, P < 0.001; -0.412, P < 0.001; -0.553, P < 0.001; -0.464, P < 0.001; -0.450, P < 0.001 for each ROls respectively). The youth and middle-aged group, the youth and elderly group had statistically significant difference (P < 0.05); however, the middle-aged and elderly group had no difference (P > 0.05). Conclusion: The shorter PLD is suitable for the youth group and 1525 ms is the best PLD. The longer PLD is suitable for the middle-aged group and elderly group and 3025ms is the best PLD. Most brain regional CBF parameters decrease with age and gradually reach a plateau after middle age.