Variable-blipped-EPI (VB-EPI) for Lower Acoustic Noise and Higher Efficiency with non-Cartesian iterative Reconstruction

Echo-Planar-Imaging¹ (EPI) with trapezoidal Readout (RO) and blipped Phase-Encoding (PE) gradients gives a high level of acoustic noise². To reduce acoustic noise we suggest prolonging the duration of the blipped PE gradient in combination with a sinusoidal or trapezoidal RO gradient and continuous data sampling throughout the whole RO train. This results in a variable density sampling along PE (less dense at the edges, denser in the centre of k-space) with a non-Cartesian trajectory, where we use ESPIRiT³ to reconstruct the data. The efficiency is improved due to continuous data sampling, resulting also in a reduced echo time.