Focal and diffuse myocardial fibrosis both contribute to regional hypoperfusion assessed by post-processing...

Area of Science:

• Cardiovascular Imaging
• Myocardial Perfusion Imaging
• Cardiac MRI

Background:

• Cardiovascular magnetic resonance imaging (CMR) is increasingly used to evaluate myocardial ischemia and viability.
• Traditional methods like first-pass perfusion and late gadolinium enhancement (LGE) have limitations in detecting balanced ischemia and diffuse fibrosis.
• Quantitative perfusion (QP) and extracellular volume (ECV) offer potential solutions by measuring absolute myocardial blood flow (MBF) and diffuse fibrosis.

Purpose of the Study:

• To investigate the utility of post-processing techniques for quantifying pixelwise MBF and diffuse fibrosis in patients undergoing clinically indicated stress-CMR exams.
• To assess if focal and diffuse myocardial fibrosis, along with other quantified CMR features, explain individual MBF findings.

Main Methods:

• A prospective observational study included 109 patients undergoing clinically indicated stress-CMR.
• Quantitative perfusion (QP) was used to measure MBF during regadenoson stress.
• T1 mapping was employed to calculate extracellular volume (ECV) for diffuse fibrosis assessment.

Main Results:

• QP analysis quantified global and regional perfusion, identifying abnormalities beyond visual assessment.
• ECV analysis detected diffuse fibrosis in areas without LGE.
• Multivariable analysis revealed LGE and ECV as independent predictors of reduced MBF (p<0.001).
• In patients without visual perfusion deficits, age and wall thickness also predicted poor MBF (p<0.001).

Conclusions:

• Quantitative analysis of MBF and ECV identifies regional tissue abnormalities missed by traditional visual assessment in stress-CMR.
• Multi-parametric quantitative analysis holds promise for refining the etiological work-up of myocardial ischemia.
• These advanced techniques may provide deeper insights into ischemic heart disease management.