Quantification of myocardial perfusion using free-breathing MRI and prospective slice tracking.

Quantification of myocardial perfusion using first-pass magnetic resonance imaging (MRI) is hampered by respiratory motion of the heart. Prospective slice tracking (PST) potentially overcomes this problem, and may provide an attractive alternative or supplement to current breath-hold techniques. This study demonstrates the feasibility of patient-adapted 3D PST on a 3.0 Tesla MR system. Eight patients underwent free-breathing studies of myocardial perfusion, simultaneously collecting data with and without PST. On average, PST reduced residual in-plane motion by a factor of 2, compared to the noncorrected images, resulting in a fourfold improvement of perfusion measurements. In addition, a comparison of perfusion measurements performed with and without PST showed that through-plane motion can contaminate measurements of myocardial perfusion. However, the quality of the navigator echoes on this field strength constituted a major source of error and needs further improvement to increase the accuracy and robustness of the method.