Functional magnetic resonance imaging using PROPELLER‐EPI

Periodically rotated overlapping parallel lines with enhanced reconstruction‐echo‐planar imaging (PROPELLER‐EPI) is a multishot technique that samples k‐space by acquisition of narrow blades, which are subsequently rotated until the entire k‐space is filled. It has the unique advantage that the center of k‐space, and thus the area containing the majority of functional MRI signal changes, is sampled with each shot. This continuous refreshing of the k‐space center by each acquired blade enables not only sliding‐window but also keyhole reconstruction. Combining PROPELLER‐EPI with a fast gradient‐echo readout scheme allows for high spatial resolutions to be achieved while maintaining a temporal resolution, which is suitable for functional MRI experiments. Functional data acquired with a novel interlaced sequence that samples both single‐shot EPI and blades in an alternating fashion suggest that PROPELLER‐EPI can achieve comparable functional MRI results. PROPELLER‐EPI, however, features different spatiotemporal characteristics than single‐shot EPI, which not only enables keyhole reconstruction but also makes it an interesting alternative for many functional MRI applications. Magn Reson Med, 2012. © 2011 Wiley Periodicals, Inc.