Assessment of Skeletal Muscle Microperfusion Using MRI

Abstract

Blood oxygenation level-dependent (BOLD) MRI, arterial spin labeling (ASL) and dynamic contrast enhancement (DCE) are current magnetic resonance imaging (MRI) techniques allowing the non-invasive functional assessment of peripheral microvasculature in healthy and diseased individuals. The functional imaging of skeletal muscle microvasculature helps to understand muscular and vascular physiology and alterations of microcirculation under certain pathological conditions such as peripheral arterial occlusive disease, diabetes mellitus, chronic compartment syndrome and rheumatic disorders. BOLD MRI uses blood as an endogenous contrast agent provided by the different magnetic properties of oxy- and deoxyhemoglobin. The BOLD contrast in skeletal muscle tissue primarily arises from the microcirculation yielding a very sensitive tool for alterations of the physiological oxygen supply and demand. However, the complex nature of the BOLD contrast’s origin also entails a variety of variables complicating the interpretation of BOLD signal changes. ASL’s ability to directly measure muscle perfusion may prove to be a powerful tool for the evaluation of disease progression and the evaluation of therapies aimed at improving muscle perfusion. As is the case with BOLD MRI, this holds particularly true for patients who are unable to receive contrast agents, a collective which is often afflicted with vascular impairments. Dynamic contrast enhanced MRI may contribute considerably to objectively evaluate many musculoskeletal diseases through its ability to measure multiple microvascular properties. The potential of these three MRI methods to non-invasively assess disease severity and the efficacy of new therapeutic strategies, such as stem cell and gene therapy, renders them as very appealing future research targets.KeywordsArterial Spin LabelMean Transit TimeBold SignalArterial Input FunctionBold ResponseThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.