Highly accelerated, millimeter in-plane resolution myocardial perfusion imaging using a 32-channel 3.0 T MR system

Abstract

Purpose: In current clinical practice perfusion MRI is generally confined to 3–4mm in-plane resolution due to the competing constraints of the short first passage of contrast agent, temporal resolution, anatomic coverage, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). The synergy between the SNR advantages of many element coil arrays and high magnetic field strengths together with the speed benefit of parallel imaging can overcome these difficulties. To approach this goal, this study examines the applicability of highly accelerated first pass perfusion imaging with millimeter in-plane spatial resolution, which preserves single-heart-beat temporal resolution. Methods: Patient studies were performed using a 3.0 Tesla MR system (Philips, Best, Netherlands), a cardiac optimized 32-element coil array (INVIVO Corp., Gainsville, FL, USA) and an ECG-gated 2D saturation recovery technique (FOV=(31×31)cm2, matrix=256×256, number of slices=3, 1 R-R interval temporal resolution). To achieve high accelerations (R=8–12) without prohibitive noise amplification associated with coil sensitivity encoding (SENSE), spatio-temporal correlations were exploited using k-t BLAST and k-t SENSE (1). Results: The highly accelerated approach yielded image quality superior to that of the conventional approach, primarily as a result of the substantial improvement in the in-plane spatial resolution and the suppression of Gibbs ringing artifacts. The ability to produce millimeter in-plane spatial resolution serves to improve myocardial perfusion assessment and supports an extension of the perfusion assessment to the right ventricle. Conclusion: The SNR and speed advantages presented here hold the promise of extending the capabilities of perfusion imaging using single-heart-beat, multi-slice 2D acquisitions to whole heart coverage 3D acquisitions.