Related Experiment Video
Updated: Jun 24, 2026
Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
Evaluation of MR-derived cerebral oxygen metabolic index in experimental hyperoxic hypercapnia, hypoxia, and ischemia
Hongyu An1, Qingwei Liu, Yasheng Chen
1Department of Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. hongyuan@med.unc.edu
Background And Purpose:
A noninvasive MRI method to measure cerebral oxygen metabolism has the potential to assess tissue viability during cerebral ischemia. The purposes of this study were to validate MR oxygenation measurements across a wide range of global cerebral oxygenation and to examine the spatiotemporal evolution of oxygen metabolism during focal middle cerebral artery occlusion in rats.
Methods:
A group of rats (n=28) under normal, hyperoxic hypercapnia and hypoxia were studied to compare MR-measured cerebral oxygen saturation (O(2)Sat(MRv)) with blood gas oximetry measurements in the jugular vein (O(2)Sat(JV)) and superior sagittal sinus (O(2)Sat(SSS)). In a separate group of rats (n=31), MR-measured cerebral oxygen metabolic index (MR_COMI) was acquired at multiple time points during middle cerebral artery occlusion. Histogram analysis was performed on the normalized MR_COMI (rMR_COMI) to examine evolution of oxygen metabolism during acute ischemia.
Results:
Highly linear relationships were obtained between O(2)Sat(MRv) and O(2)Sat(JV)/O(2)Sat(SSS) in rats under global cerebral oxygenation alterations. In the focal ischemia study, rMR_COMI values were significantly lower within the areas of eventual infarction than other regions. Moreover, the rMR_COMI values within the ischemic territory decreased with time, concomitant with an increase in the number of voxels with severely impaired oxygen metabolism.
Conclusions:
Accurate estimates of O(2)Sat(MRv) can be obtained across a broad and physiologically relevant range of cerebral oxygenation. Furthermore, this method demonstrates a dynamic alteration of cerebral oxygen metabolism during acute ischemia in rats.
