Magnetic resonance quantification of the myocardial perfusion reserve with a Fermi function model for constrained...

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Physiology

Background:

• Myocardial perfusion reserve (MPR) is crucial for evaluating coronary artery lesion significance.
• Assessing regional tissue perfusion noninvasively is vital for diagnosing cardiac conditions.

Purpose of the Study:

• To apply rapid magnetic resonance (MR) imaging for noninvasive measurement of myocardial perfusion reserve.
• To validate a Fermi function model using Monte Carlo simulations for MR-based perfusion assessment.

Main Methods:

• Utilized rapid MR imaging with a bolus-injected contrast agent to measure myocardial blood flow at rest and hyperemia.
• Employed a Fermi function model to fit MR signal curves and calculate MPR from impulse response amplitudes.
• Validated model assumptions and performance using Monte Carlo simulations with a detailed blood-tissue exchange model.

Main Results:

• Demonstrated a linear relationship between the ratio of impulse response amplitudes and the ratio of blood flows under specific conditions (CNR 6:1, flow 0.5–4.0 ml/min/g, input function transit time < 9 s).
• Identified increased uncertainty in blood flow reserve estimates at very low (< 1.0 ml/min/g) and high (> 3–4 ml/min/g) flow rates.
• MR perfusion reserve in the LAD territory correlated linearly with intracoronary Doppler ultrasound flow reserve (r = 0.84) in patients without significant coronary artery disease.

Conclusions:

• Rapid MR imaging provides a reliable method for assessing myocardial perfusion reserve.
• The study validates the use of a Fermi function model and Monte Carlo simulations for accurate perfusion quantification.
• MR-derived MPR shows strong correlation with established methods like Doppler ultrasound, supporting its clinical utility.