Characterising Skeletal Muscle Perfusion Using Fractional Fickian Modeling of Diffusion MRI

Perfusion of blood through the microcirculatory system is a key component of in vivo cellular metabolism, and thus central in the pathophysiology of skeletal muscle. Development of reliable and feasible quantitative imaging of microcirculation is an active area of research. Diffusion weighted (DW) magnetic resonance imaging is a flexible modality for probing incoherent water molecular motions over a wide range of length scales. The multi-scale structures of both muscle and its vascular system exhibit power-law properties giving rise to anomalous diffusion processes. Here, we describe a fractional Fickian diffusion model, which provides a parsimonious representation of anomalous super-diffusion. This model is numerically stable under in vivo imaging conditions and is able to capture molecular velocities consistent with skeletal muscle perfusion at rest and under stress. We present model fit results from DW images of human skeletal muscle both at rest and under post-exercise hyperemia. We provide interpretation of fractional Fickian model parameters in the context of skeletal muscle microvascular volume based on published invasive measures.

David currently works at Emory University in the Department of Radiology and Imaging Sciences and the Department of Orthopedics. His lab continues to develop quantitative MRI and MRS approaches for addressing basic and applied research questions primarily in the musculoskeletal system. 

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