Patient adaptive maximal resolution magnetic resonance myocardial stress perfusion imaging.

Purpose: To demonstrate the feasibility of an automatic adaptive acquisition sequence. Magnetic resonance perfusion pulse sequences often leave potential acquisition time unused in patients with lower heart-rates (HR) and smaller body size.
Materials and Methods: A perfusion technique was developed that automatically adapts to HR and field-of-view by maximizing in-plane spatial resolution while maintaining temporal resolution every cardiac cycle. Patients (n = 10) and volunteers (n = 10) were scanned with both a standard resolution and adaptive method. Image quality was scored, signal-to-noise ratio (SNR) calculated, and width of dark-rim artifact (DRA) measured.
Results: The acquired spatial resolution of the adaptive sequence (1.92 × 1.92 mm(2)  ± 0.34) was higher than the standard resolution (2.42 × 2.42 mm(2) ) (P < 0.0001). Mean DRA width was reduced using the adaptive pulse sequence (1.94 ± 0.60 mm vs. 2.82 ± 0.65 mm, P < 0.0001). The signal-to-noise ratio (SNR) was higher with the standard pulse sequence (6.7 ± 2.2 vs. 3.8 ± 1.8, P < 0.0001). There was no difference in image quality score between sequences in either volunteers (1.1 ± 0.31 vs. 1.0 ± 0.0, P = 0.34) or patients (1.3 ± 0.48 vs. 1.3 ± 0.48, P = 1.0).
Conclusion: Optimizing the use of available imaging time during first-pass perfusion with a magnetic resonance imaging pulse sequence that adapts image acquisition duration to HR and patient size is feasible. Acquired in-plane spatial resolution is improved, the DRA is reduced, and while SNR is reduced with the adaptive sequence consistent with the lower voxel size used, image quality is maintained.
(© 2015 Wiley Periodicals, Inc.)