Multi-phase 3D arterial spin labeling brain MRI in assessing cerebral blood perfusion and arterial transit times in children at 3T.

BACKGROUND: 3D pseudocontinuous arterial spin labeling (pCASL) with a single post-labeling delay time is commonly used to measure cerebral blood flow (CBF). Multi-phase pCASL has been developed to simultaneously estimate CBF and arterial transit time (ATT).

PURPOSE: To evaluate the clinical feasibility of multi-phase 3D pCASL in pediatric patients, and to compare the estimation of ATT and CBF via linear weighted-delay and traditional non-linear iterative curve-fitting routines.

MATERIAL & METHODS: Forty patients (average age: 8.6 y, 5 d-22.4 y) referred for routine brain MRI underwent additional 5-7 min of pCASL scans at 3T using 5 PLDs between 300 and 2300 ms. Data were post-processed by two algorithms for estimating CBF and ATT. Average CBF and ATT values were computed for vascular territories including the anterior, middle and posterior cerebral arteries as well as regions based on the Alberta Stroke Program Early CT Score template. Pearson correlation coefficients and linear regression were used for statistical analysis. The clinical value of multi-phase CASL was evaluated by a neuroradiologist based on asymmetric CBF and ATT maps in patients.

RESULTS: All pCASL scans were successfully completed, generating diagnostic results. CBF computed from weighted-delay and curve-fitting methods agreed strongly, with Pearson correlation coefficients ranging from 0.97-0.99 across the measured regions (p < 0.05). Correlation coefficients for ATT ranged from 0.87-0.96 (p < 0.05). CBF and ATT maps were found to add valuable information to clinical diagnosis in 17 of 40 pediatric patients.

CONCLUSION: Our preliminary results demonstrate the feasibility and potential clinical utility of multi-phase pCASL for simultaneous CBF and ATT quantification in pediatric patients.