Reproducibility of continuous arterial spin labeling perfusion MRI after 7 weeks

Background Continuous arterial spin labeling (CASL) is a non-invasive technique for the measurement of cerebral blood flow (CBF). The aim of the present study was to examine the reproducibility of CASL measurements and its suitability to consistently detect differences between groups, regions, and resting states. Materials and methods Thirty-eight healthy subjects (19 female) were examined at 1.5 T on two measurement occasions that were seven weeks apart. Resting CBF was measured with eyes open and eyes closed. Results In different regions of interest (ROIs) the repeatability estimates varied between 9 and 19 ml/100 g/min. There were no significant mean differences between occasions in all ROIs (P > 0.05). Greater CBF in the eyes-open than in the eyes-closed state was consistently present in the primary and secondary visual areas. Furthermore, CBF was consistently greater in the right than in the left hemisphere (P < 0.05) and differed between lobes and between arterial territories (P < 0.001). Finally, we consistently observed greater CBF in women than in men (P < 0.001). Conclusion This study demonstrates the suitability of CASL to consistently detect differences between groups, regions, and resting states even after seven weeks. This emphasizes its usefulness for longitudinal designs.