Simultaneous non-contrast assessment of myocardial microstructure and perfusion in multiple cardiac phases at stress and rest

Motivation: Simultaneous non-contrast quantitation of myocardial microstructure and perfusion has tremendous potential for diagnosis and prognosis in ischemic and non-ischemic heart disease. Goal(s): Demonstrate co-localised perfusion and microstructure quantitation using stimulated echo intravoxel incoherent motion (STEAM-IVIM) in multiple cardiac phases and during vasodilator stress. Approach: Computational simulations to derive an optimal set of b-values for efficient estimation of diffusion and perfusion quantification. Demonstration of STEAM-IVIM at rest, adenosine stress and in diastole and systole in-vivo. Results: Rest diastole and systole and stress STEAM-IVIM was acquired in 5 volunteers. During stress the perfusion fraction increases and diffusion tensor analysis demonstrates the expected dynamic microstructural changes. Impact: STEAM-IVIM holds great potential for future studies in patient cohorts, delivering simultaneous intrinsically co-registered assessment of inducible ischemia and microstructure, providing new insights into the microstructural and microvascular underpinnings of heart diseases.