Steady-state first-pass perfusion (SSFPP): A 3D TWIST in myocardial first-pass perfusion imaging

Abstract

Summary A new approach to myocardial first-pass perfusion imaging is presented; this technique, called SSFPP, is based on 3D SSFP sequence whereby magnetization is maintained in constant steady-state, while data acquisition is gated to diastole. This results in high SNR and CNR, and other characteristics that can potentially mitigate dark rim artifacts. The high-blood myocardial contrast of SSFP allows automatic segmentation, which, combined with registration, facilitates image analysis. Background Although introduced in 1990, myocardial first-pass perfusion imaging has not yet become a routine diagnostic tool, primarily because of insufficient image quality, insufficient coverage, and dark rim artifacts (DRA). Current techniques rely on a saturation recovery (SR) preparation for T1 contrast, resulting in poor SNR, low efficiency, and k-space modulation during SR. Further, the post-processing of these images is tedious. In this work, we propose an alternative perfusion imaging technique, called Steady-State First Pass Perfusion (SSFPP). Objective To develop a new 3D first-pass perfusion imaging technique that can potentially address the limitations of current methods. Theory SSFPP is a 3D SSFP sequence in which the magnetization is maintained in constant steady-state while the data acquisition is gated to diastole. The SNR and CNR are similar to those in SSFP cine imaging, allowing the use of automatic segmentation algorithms. Furthermore, the tissue contrast is dependent on T1/T2; serendipitously, this causes blood signal to remain almost constant, whereas the myocardial signal exhibits a nearly linear correlation with contrast agent concentration. Maintenance of steady-state throughout data acquisition avoids k-space modulation, and the elimination of saturation recovery time increases data acquisition efficiency by reducing deadtime. Methods