Investigation of brain hemodynamic changes induced by active and passive movements: a combined arterial spin labeling-BOLD fMRI study.

PURPOSE

To assess the applicability of arterial spin labeling (ASL) in comparison to blood-oxygenation-level-dependent (BOLD) contrast fMRI in detecting brain activations elicited by active and passive hand movements.

MATERIALS AND METHODS

A block design for ASL and BOLD fMRI was applied in 8 healthy subjects using active and passive hand tasks. Data analyses were performed at individual and group level, comparing both the different movements and the performance of the two techniques.

RESULTS

Group analyses showed involvement of the same areas during both tasks, as the contralateral sensorimotor cortex, supplementary motor area, cerebellum, inferior parietal lobes, thalamus. ASL detected smaller activation volumes than BOLD, but the areas had a high degree of colocalization. Few significant differences (P < 0.05) were found when the two tasks were compared for the number of activated voxels, coordinates of center of mass, and CBF estimates. Considering together all the areas, the mean %BOLD change was 0.79 ± 0.27 and 0.73 ± 0.24 for the active and passive movements respectively, while the mean %CBF changes were 34.1 ± 8.9 and 27.1 ± 14.8.

CONCLUSION

Our findings confirm passive and active tasks are strongly coupled, supporting the importance of passive tasks as a diagnostic tool in the clinical setting. ASL fMRI proved suitable for functional mapping and quantifying CBF changes, making it a promising technique for patient cohort applications.