Denoising high angular resolution diffusion imaging data by combining singular value decomposition and non local means filter
BACKGROUND High angular resolution diffusion imaging (HARDI) data is typically corrupted with Rician noise. Although larger b values help to retrieve more accurate angular diffusivity information, they also lead to an increase in noise generation. NEW METHOD In order to sufficiently reduce noise in HARDI images and improve the construction of orientation distribution function (ODF) fields, a novel denoising method was developed in this study by combining the singular value decomposition (SVD) and non local means (NLM) filter. Similar 3D patches were first recruited into a matrix from a search volume. HARDI signals in the matrix were then re estimated using the SVD low rank approximation, and a NLM filter was employed to filter out any residual noise. RESULTS The performance of the proposed method was evaluated against the state of the art denoising methods based on both synthetic and real HARDI datasets. Results demonstrated the superior performance of the developed SVD NLM method in denoising HARDI data through preserving fine angular structural details and estimating diffusion orientations from improved ODF fields. CONCLUSION The proposed SVD NLM method can improve HARDI quantitative computations, such as MRI brain tissue segmentation and diffusion profile estimation, that rely on the quality of imaging data.
Journal of Neuroscience Methods