Wave‐CAIPI for highly accelerated MP‐RAGE imaging

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Purpose To introduce a highly accelerated T1‐weighted magnetization‐prepared rapid gradient echo (MP‐RAGE) acquisition that uses wave‐controlled aliasing in parallel imaging (wave‐CAIPI) encoding to retain high image quality. Methods Significant acceleration of the MP‐RAGE sequence is demonstrated using the wave‐CAIPI technique. Here, sinusoidal waveforms are used to spread aliasing in all three directions to improve the g‐factor. Combined with a rapid (2 s) coil sensitivity acquisition and data‐driven trajectory calibration, we propose an online integrated acquisition‐reconstruction pipeline for highly efficient MP‐RAGE imaging. Results The 9‐fold accelerated MP‐RAGE acquisition can be performed in 71 s, with a maximum and average g‐factor of g max = 1.27 and g avg = 1.06 at 3T. Compared with the state‐of‐the‐art method controlled aliasing in parallel imaging results in higher acceleration (2D‐CAIPIRINHA), this is a factor of 4.6/1.4 improvement in g max /g avg . In addition, we demonstrate a 57 s acquisition at 7T with 12‐fold acceleration. This acquisition has a g‐factor performance of g max = 1.15 and g avg = 1.04. Conclusion Wave encoding overcomes the g‐factor noise amplification penalty and allows for an order of magnitude acceleration of MP‐RAGE acquisitions. Magn Reson Med 79:401–406, 2018.