Dual Gradient-Echo Imaging of Ischemia/Reperfusion in Skeletal Muscle
Damon B, Hornberger J, Kent-Braun J
Vanderbilt University, Vanderbilt University
Brief MRI signal intensity transients have been reported following short isometric contractions and may be useful indices of vascular function in applied physiology and pathophysiology studies. While generally reflecting a muscle BOLD response, their exact physiological mechanism remains unclear. Using dual gradient-echo EPI acquisitions (TE/TE=1000/6, 46 ms) and near-infrared spectroscopy measurements of total hemoglobin and oxyhemoglobin saturation obtained during 5 min of suprasystolic blood pressure cuff inflation, we show here that short-echo signals reflect changes in blood volume and long-echo signals reflect changes in blood oxygenation.