Hyperintense signals in cerebral blood flow maps acquired with pseudo-continuous arterial spin labeling MRI in mice

We found that hyperintense signals in mice extend to arteries, major veins, and ventricular structures (e.g., choroid plexus). Such a pattern was different from human pCASL images, where hyperintense signals are predominantly present in arteries. Statistical analyses supported a PLD of 500 ms as a pragmatic balance between detection sensitivity and suppression of vascular contamination. Additional experiments and numerical simulations showed that, within the tested range, stronger crusher gradients provided little extra vascular suppression-primarily because large vessel calibers relative to small voxels limit intravoxel phase dispersion. These findings refine the interpretation of murine pCASL signals and facilitate more accurate perfusion imaging in preclinical pathophysiological studies.