PROPELLER EPI Using Asymmetric Blades: A Preliminary Study on Point Spread Function

Several methods were proposed to reduce the susceptibility-induced blurring effect of long-axis PROPELLER (LAP) EPI. [1,2] Skare et al. suggested using an alternative short-axis PROPELLER (SAP) EPI to reduce the geometric distortion by shortening the echo spacing. In order to achieve comparable SNR, which is an advantage of LAP by reducing TE, half Fourier blades was implemented in SAP method. In this study, we applied analogous concept to LAP by using asymmetric numbers of phase encoding (PE) lines between two sides of k space center. Point spread functions (PSF) of LAP EPI with symmetric and asymmetric blades are investigated to characterize their blurring effect.