Sevgi Gokce Kafali1,2, Tolga Çukur1,2, and Emine Ulku Saritas1,2
1Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey, 2National Magnetic Resonance Research Center (UMRAM), Bilkent University, Ankara, Turkey
Diffusion-weighted
imaging (DWI) intrinsically suffers from low SNR due to diffusion-induced
signal losses. Multiple acquisitions have to be averaged to attain reasonable
SNR level in high-spatial-resolution DWI images. However, subject motion during
diffusion-sensitizing gradients creates varying phase offsets between repeated
acquisitions, prohibiting a direct complex averaging of the image repetitions. Here,
we propose a phase-correcting non-local means denoising filter that combines
multiple DWI acquisitions while effectively reducing noise and phase
cancellations. Results are demonstrated in vivo in the cervical spinal cord at
3T, using a reduced field-of-view DWI with 0.9 x 0.9 mm2 in-plane
resolution.
