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Comparison and optimization of pCASL and VSASL for rat thoracolumbar spinal cord MRI at 9.4 T. Magn Reson Med 2023 Jun;89(6):2305-2317



Pubmed ID


Pubmed Central ID




Scopus ID

2-s2.0-85147533572 (requires institutional sign-in at Scopus site)


PURPOSE: To evaluate pseudo-continuous arterial spin labeling (pCASL) and velocity-selective arterial spin labeling (VSASL) for quantification of spinal cord blood flow (SCBF) in the rat thoracolumbar spinal cord.

METHODS: Labeling efficiency (LE) was compared between pCASL and three VSASL variants in simulations and both phantom and in vivo experiments at 9.4 T. For pCASL, the effects of label plane position and shimming were systematically evaluated. For VSASL, the effects of composite pulses and phase cycling were evaluated to reduce artifacts. Additionally, vessel suppression, respiratory, and cardiac gating were evaluated to reduce motion artifacts. pCASL and VSASL maps of spinal cord blood flow were acquired with the optimized protocols.

RESULTS: LE of the descending aorta was larger in pCASL compared to VSASL variants. In pCASL, LE off-isocenter was improved by local shimming positioned at the label plane and the anatomical level of labeling for the thoracic cord was only viable at the level of the T10 vertebra. Cardiac gating was essential to reduce motion artifacts. Both pCASL and VSASL successfully demonstrated comparable SCBF values in the thoracolumbar cord.

CONCLUSION: pCASL demonstrated high and consistent LE in the thoracic aorta, and VSASL was also feasible, but with reduced efficiency. A combination of cardiac gating and recording of actual post-label delays was important for accurate SCBF quantification. These results highlight the challenges and solutions to achieve sufficient ASL labeling and contrast at high field in organs prone to motion.

Author List

Lee S, Meyer BP, Hernandez-Garcia L, Kurpad SN, Schmit BD, Budde MD


Matthew Budde PhD Associate Professor in the Neurosurgery department at Medical College of Wisconsin
Shekar N. Kurpad MD, PhD Chair, Director, Professor in the Neurosurgery department at Medical College of Wisconsin
Brian Schmit PhD Professor in the Biomedical Engineering department at Marquette University

MESH terms used to index this publication - Major topics in bold

Blood Flow Velocity
Cerebrovascular Circulation
Magnetic Resonance Angiography
Magnetic Resonance Imaging
Spin Labels