Functional arterial spin labeling: Optimal sequence duration for motor activation mapping in clinical practice

Purpose:

To determine the minimal optimal functional arterial spin labeling (fASL) sequence duration allowing steady and reproducible motor activation mapping.

Materials and Methods:

Three magnetic resonance imaging (MRI) sessions including fASL and blood oxygenation level‐dependent (BOLD) functional MRI (fMRI) sequences were performed on 12 healthy subjects at 3T with a 32‐channel coil. The raw 7‐minute fASL sequence was truncated to obtain six fASL sequences with durations ranging from 1–6 minutes. All the resulting fASL activations were compared between themselves and with both the 7‐minute fASL and BOLD activations. Quantitative parameters assessed activation location (activated volume, barycenter, and distance between barycenters), activation quantification (activation‐related cerebral blood flow), and intraindividual reproducibility across fMRI sessions. The statistical analysis was based on analysis of variance (ANOVA) and Tukey's multiple comparisons.

Results:

Four‐minute fASL achieved steady location and quantification of activation with the activated volume corresponding to 81% of the 7‐minute fASL volume and a barycenter located 1.2 mm from the 7‐minute fASL barycenter and 3.0 mm from the BOLD fMRI barycenter. Four‐minute fASL reproducibility was high and statistically equivalent to 7‐minute values.

Conclusion:

A 4‐minute fASL sequence is thus a reliable tool for motor activation mapping and suitable for use in clinical practice. J. Magn. Reson. Imaging 2012; 36:1435–1444. © 2012 Wiley Periodicals, Inc.