MEASUREMENT OF CORONARY BLOOD-FLOW VELOCITY DURING HANDGRIP EXERCISE USING BREATH-HOLD VELOCITY-ENCODED CINE MAGNETIC-RESONANCE-IMAGING

Since the first clinical application of the concept of coronary flow r eserve, defined as the ratio of hyperemic flow to flow at rest, for th e assessment of significance of coronary artery disease,(1-3) several studies have been performed using various invasive and noninvasive tec hniques to determine coronary flow reserve in humans.(4-7) With the in troduction of rapid, segmented k-space breathholding techniques, visua lization of the left and right coronary arteries has become possible.( 8,9) Additionally, the introduction of time-of-flight and phase-contra st techniques allows noninvasive blood flow velocity measurements in t he coronary arteries in vivo.(10-13) A recent study demonstrated the f easibility of fast velocity encoded cine magnetic resonance imaging (M RI) with k-space segmentation and view sharing reconstruction for disp laying phasic coronary flow velocity curve in the cardiac cycle.(14) T he purpose of the present study was to assess the applicability of bre athhold velocity encoded cine (VEC)-MRI for measuring the increase in coronary blood flow velocity in response to interventions in normal su bjects.