Measuring flow in the right coronary artery with magnetic resonance imaging.

摘要

Coronary artery disease is the leading cause of death in the United States. Currently, there is no non-invasive test to diagnose and monitor this disease. Phase contrast MRI flow measurements have been verified as a non-invasive means to detect flow abnormalities in the left coronary artery, the site of most coronary stenoses. The goal of this dissertation is to measure flow in the second most common stenosis site, the right coronary artery, with MRI. To this end, acquisition, reconstruction, and analysis issues are investigated using simulations, phantoms, and volunteers.;Acquisition of right coronary artery flow images must result in a well visualized vessel with accurate flow measurements. To accomplish this, a fast gradient echo pulse sequence with echo train readout is chosen for imaging. Recommendations are made for the echo train length, views per segment, bandwidth, number of excitations, phase field of view, flip angle, coil, velocity encode order, and phase encode order that optimize visualization and accuracy.;Velocity view-sharing, a reconstruction technique that doubles the effective temporal resolution of a phase contrast scan, is described and implemented. Through investigation of reconstruction segment interpolation schemes, a linear interpolation filter is found to be preferred over a nearest neighbor filter for tagged acquisitions, which gives insight for RCA imaging. This may be useful for flow when linear interpolation becomes available for fast gradient echo phase-contrast with echo train readout.;Measurement of oblique vessel flow ideally is the same as non-oblique flow. However, a mismatch between the signal magnitudes of the flowing material and background is shown to create an error in the velocity values. This error cannot be eliminated or corrected for, but minimizing the slice obliquity and thickness will reduce the partial volume in the edge pixels and decrease the error.;These investigations allowed flow in the right coronary artery of a patient to be imaged. The velocity measurements in this early patient are compared to Doppler measurements and the feasibility of the technique is established.