Multiplexed EPI at 9.4T with PSF-Based Distortion Correction

Seong Dae Yun¹, Nadim Jon Shah¹, ²

The relatively high imaging speed of EPI has led to its widespread use in dynamic MRI studies. For even faster acquisition of multiple slices in EPI, M-EPI (Multiplexed EPI) method has been recently presented (Feinberg et al.). However, because of the intrinsically low bandwidth in the phase encode direction, EPI-based methods are highly sensitive to field inhomogeneities, which results in potentially severe geometric distortions. This problem becomes more challenging at ultra-high fields such as 9.4T. The present work verifies i) the use of M-EPI at 9.4T and ii) demonstrates the application of the PSF (Point Spread Function)-based correction method to the M-EPI images to remove the geometric distortions.