Michael Charles Langham1, Cheng Li1,
Emile R. Mohler III2, Jeremy Magland1, Felix Werner
Wehrli1
1Radiology, University of
Pennsylvania, Philadelphia, PA, United States; 2Medicine,
University of Pennsylvania, Philadelphia, PA, United States
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.