Isotropic anomalous filtering in Diffusion-Weighted Magnetic Resonance Imaging

Abstract

Noise is inherent to Diffusion-Weighted Magnetic Resonance Imaging (DWI) and noise reduction methods are necessary. Although process based on classical diffusion is one of the most used approaches for digital image, anomalous diffusion has the potential for image enhancement and it has not been tested for DWI noise reduction. This study evaluates Anomalous Diffusion (AD) filter as DWI enhancement method. The proposed method was applied to magnetic resonance diffusion weighted images (DW-MRI) with different noise levels. Results show better performance for anomalous diffusion when compared to classical diffusion approach. The proposed method has shown potential in DWI enhancement and can be an important process to improve quality in DWI for neuroimage-based diagnosis.

Anisotropic anomalous diffusion filtering applied to relaxation time estimation in magnetic resonance imaging

“…In the literature research is found that supports the anomalous behavior in the MRI signal decay [9] and other anomalous highlights involved to brain images [10]. Furthermore, the AAD filter demonstrates potential to enhance MRI diffusion weighted image quality [8], and this applicability is hereby extended to relaxometry images.…”

“…1 in several biomedical image techniques. However, in recent studies it has been shown that AAD filtering (resulting by porous media equation [7]) has a better filtering performance than the classical diffusion approach when it is applied to MRI brain imaging [8].…”

“…The σ values chosen to filter each image with a determined noise add was: σ 15 = 1.5, σ 30 = 1.0 and σ 60 = 1.0 respectively. For the AAD filter we used the q value setup as q = 1.3 which it is a optimized value for MRI images[8]. The filtering parameters values for NLM (h = 1.5σ) and Gaussian (σ = 1.0) filter were selected based on the literature[5].…”