Myocardial perfusion reserve: assessment with multisection, quantitative, first-pass MR imaging

Area of Science:

• Cardiovascular imaging
• Magnetic resonance imaging
• Myocardial perfusion assessment

Background:

• Assessing myocardial blood flow and perfusion reserve is crucial for diagnosing coronary artery disease.
• Non-invasive imaging techniques are needed to accurately quantify myocardial perfusion.
• Magnetic resonance (MR) first-pass imaging offers potential for evaluating myocardial perfusion.

Purpose of the Study:

• To establish the feasibility of using MR first-pass imaging to determine myocardial blood flow and perfusion reserve.
• To validate MR findings against radiolabeled microsphere measurements in an animal model.
• To compare MR-derived perfusion reserve with coronary flow reserve in patients with non-significant coronary lesions and angina.

Main Methods:

• Arrhythmia-insensitive, first-pass, multisection, T1-weighted MR imaging with contrast enhancement was used.
• Eight pigs underwent MR imaging and parallel radiolabeled microsphere flow measurements during acute ischemia.
• Eight patients underwent MR imaging and intracoronary Doppler flow ultrasound measurements for coronary flow reserve.

Main Results:

• A linear correlation (r = .88, P < .01) was observed between MR perfusion indexes and microsphere flow measurements in pigs.
• In patients, the regional perfusion reserve measured by MR imaging showed strong agreement with the coronary flow reserve (r = .80).
• The regression analysis indicated a slope of 1.02 +/- 0.09, demonstrating a near 1:1 relationship.

Conclusions:

• First-pass MR imaging is a feasible method for quantifying myocardial perfusion reserve.
• The study validates MR first-pass imaging against established methods in both animal and human studies.
• MR-derived myocardial perfusion reserve accurately reflects coronary flow reserve, particularly in patients with microvascular dysfunction.