Related Experiment Video
Updated: Aug 25, 2026
Oxygenation-sensitive Cardiac MRI with Vasoactive Breathing Maneuvers for the Non-invasive Assessment of Coronary Microvascular Dysfunction
Published on: August 17, 2022
Dynamic estimation of the myocardial oxygen extraction ratio during dipyridamole stress by MRI: a preliminary study
Jie Zheng1, Jinghua Wang, Mark Nolte
1Mallinckrodt Institute of Radiology, Washington University School of Medicine, St Louis, Missouri 63110, USA. zhengj@mir.wustl.edu
Abstract:
The myocardial oxygen extraction fraction (OEF) reflects the balance between myocardial oxygen supply and demand. The feasibility of quantifying myocardial OEF was demonstrated with MRI during pharmacologic vasodilation in dogs. Dipyridamole was infused intravenously to increase blood flow and change in myocardial oxygen content. Arterial and coronary sinus blood sampling was performed during dipyridamole-induced vasodilation to measure the myocardial blood oxygen content. Myocardial T(2) was measured dynamically during the vasodilation, and quantified with a simplified diffusion model as a function of myocardial OEF and blood volume. The results showed a strong correlation (R(2) = 0.89) between myocardial OEF values measured by MRI and those measured by blood sampling. Regional differences in the OEF were demonstrated by direct infusion of dipyridamole into coronary arteries in dogs. Combined with vasodilator stress, dynamic assessments of the OEF may provide a putative measurement of myocardial flow reserve and allow consecutive monitoring of myocardial dose and response.
