103 Non-invasive measurement of coronary artery flow velocity at rest and during handgrip stress in healthy subjects using 3 T MRI

Endothelial-dependent coronary artery vasoreactivity is an important indicator of vascular function and predicts cardiovascular events [ 1 ]. In response to endothelial-dependent stressors, changes in coronary artery cross-sectional area and flow velocity occur which are typically assessed by invasive methods. Magnetic resonance flow mapping is non-invasive and validated for endothelial-independent stressors in humans by comparison with Doppler guidewire measurements [ 2 , 3 ]. One prior study [ 4 ], performed at 1.5 T and recording 7–11 cine frames per cardiac cycle, assessed coronary flow velocity during isometric handgrip exercise, a well-established provocateur of endothelial-dependent vasoreactivity [ 5 ]. As higher magnetic field strengths offer the potential for enhanced temporal and/or spatial resolution, which would support both improved image quality due to reduced blurring and more accurate quantification of diastolic peak velocity, we studied diastolic coronary flow peak velocity with 3 T MRI using spiral acquisitions. Here we describe reactive changes in coronary flow velocity using isometric handgrip exercise in healthy subjects as detected by spiral 3 T MRI with a temporal resolution of 34 ms and an in plane resolution of 0.8 × 0.8 mm.