Multiparameter Functional MRI Assessment of Vascular Reactivity

Michael Charles Langham¹, Cheng Li¹, Emile R. Mohler III², Jeremy Magland¹, Felix Werner Wehrli¹

An integrated MRI protocol is presented for quantifying various measures of vascular reactivity as surrogates for assessing endothelial dysfunction. The protocol consists of simultaneously monitoring temporally resolved arterial blood flow velocity and venous oxygen saturation (SvO2) in femoral vessels during cuff-induced reactive hyperemia, along with aortic pulse-wave velocity. Impaired vascular reactivity in patients with peripheral arterial disease was marked by increased washout time, reduced upslope and overshoot of the SvO2 versus time curve, decreased shear rate and increased arterial forward flow duration. Among healthy subjects large differences were also observed, reflecting age- and lifestyle related effects on vascular reactivity.