2025 Stress MR III In DC: A Hands-On Workshop-Day 2 - Part V: The Apex of all CV Imaging: Introduction to Quantification of Myocardial Blood Flow and Perfusion Reserve

Day 2 - Part V: The Apex of all CV Imaging: Introduction to Quantification of Myocardial Blood Flow and Perfusion Reserve

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Video Summary

The session opened with a physiology primer on myocardial blood flow and flow reserve. Dr. Jonathan Lindner explained how the heart maintains oxygen delivery by auto-regulating coronary resistance, why stenosis can be compensated at rest until severe narrowing, and how vasodilator stress reveals flow reserve limitations. He emphasized that “microvascular dysfunction” is a syndrome with multiple causes, including endothelial dysfunction, vasoconstrictor imbalance, capillary constriction, and even metabolic/myocyte abnormalities. He also highlighted that resting flow, hyperemic flow, and flow reserve each provide different clinical information.<br /><br />Dr. Peter Kelman then described quantitative cardiac MRI perfusion mapping. He outlined the first-pass gadolinium technique, the importance of arterial input function correction, motion correction, T2* correction, and kinetic modeling to estimate myocardial blood flow pixel by pixel. He also discussed newer advances such as AI denoising, higher spatial resolution imaging, improved visualization graphics, and methods to reduce blood contamination of myocardial contours.<br /><br />A case-based discussion followed, led by Dr. Amit Patel, showing how quantitative perfusion helps in multivessel CAD, chronic total occlusions, microvascular dysfunction, and elevated resting flow states. The audience debated viability, ischemic burden thresholds, and the interpretation of stress flow versus flow reserve.<br /><br />Finally, Dr. Patricia Rodriguez-Lozano presented women’s heart health cases focused on microvascular disease and ANOCA. One case involved lupus and hydroxychloroquine cardiotoxicity with reduced EF and suspected CMD. Another showed vasospastic angina diagnosed invasively despite abnormal CMR flow reserve. She ended by sharing early results from a small randomized trial suggesting a potential benefit of empagliflozin-like therapy on myocardial perfusion reserve in symptomatic women.

Keywords

myocardial blood flow

flow reserve

coronary resistance

vasodilator stress

microvascular dysfunction

endothelial dysfunction

cardiac MRI perfusion mapping

gadolinium technique

arterial input function

kinetic modeling

quantitative perfusion

multivessel CAD

ANOCA

vasospastic angina