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Updated: Aug 25, 2026
Construction and Application of Cerebral Functional Region-Based Cerebral Blood Flow Atlas Using Magnetic Resonance Imaging-Arterial Spin Labeling
Published on: May 31, 2024
Hyperintense Signals in Cerebral Blood Flow Maps of Mice Acquired with Pseudo-continuous Arterial Spin Labeling MR
Xiuli Yang1, Yuguo Li1,2, Adnan Bibic2
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Purpose:
Pseudo-continuous arterial spin labeling (pCASL) MRI is a widely used, noninvasive, contrast-agent-free technique for measuring cerebral blood flow (CBF) and assessing vascular dysfunction across diverse clinical settings and murine disease models. In practice, arterial-transit artifacts that generate hyperintense signal in CBF maps warrant careful consideration. While these effects are well characterized in humans, they are less well understood in mice owing to the marked interspecies physiological differences.
Methods:
To address this knowledge gap, we systematically characterized pCASL hyperintense signal as a function of post-labeling delay (PLD) and crusher-gradient strength in mice. Numerical simulations were also performed to validate the experimental findings.
Results:
We found that hyperintense signals in mice extend to arteries, major veins, and ventricular structures. Such a pattern was different from human pCASL images, where hyperintense signals are predominantly present in arteries. Statistical analyses supported a PLD of 500 milliseconds 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.
Conclusion:
These findings refine the interpretation of murine pCASL signals and facilitate more accurate perfusion imaging in preclinical pathophysiological studies.
Insights
Pseudo-continuous arterial spin labeling (pCASL) MRI artifacts in mice differ from humans, extending to veins and ventricles. A 500 ms post-labeling delay and stronger gradients offer limited improvement for cerebral blood flow imaging.
Area of Science:
- Neuroimaging
- Preclinical Research
Background:
- Pseudo-continuous arterial spin labeling (pCASL) MRI is a noninvasive technique for measuring cerebral blood flow (CBF).
- Arterial-transit artifacts are common in pCASL CBF maps, requiring careful interpretation.
- These artifacts are well-understood in humans but less so in mice due to physiological differences.
Purpose of the Study:
- To systematically characterize pCASL hyperintense signals in mice.
- To understand the impact of post-labeling delay (PLD) and crusher-gradient strength on these artifacts.
- To validate experimental findings with numerical simulations.
Main Methods:
- Systematic characterization of pCASL hyperintense signal in mice.
- Varying post-labeling delay (PLD) and crusher-gradient strength.
- Performing numerical simulations to validate experimental results.
Main Results:
- Hyperintense signals in mice were observed in arteries, major veins, and ventricles, unlike in humans where they are primarily arterial.
- A PLD of 500 ms was identified as optimal for balancing sensitivity and vascular suppression.
- Stronger crusher gradients showed minimal additional vascular suppression due to large vessel size relative to voxel size.
Conclusions:
- Murine pCASL signal interpretation is refined by these findings.
- Accurate perfusion imaging in preclinical studies is facilitated.
- Understanding species-specific artifact patterns is crucial for reliable CBF measurements.
