Enhancing MRI Image Quality through Deep CNN-Augmented Denoising: A Comparative Study of Standard and Hybrid Filters

Abstract

Magnetic Resonance Imaging (MRI) is commonly applied to clinical diagnostics owing to its high soft-tissue contrast and lack of invasiveness. However, its sensitivity to noise, attributable to hardware limitations, patient motion, and acquisition parameters, remains a long-term source of concern that normally leads to impaired diagnostic accuracy. Traditional denoising filters such as Gaussian, Wavelet, Anisotropic Diffusion, and Non-Local Means (NLM) have previously been employed to reduce these issues, but at the cost of typically sacrificing noise removal against structural detail. More recent advances in deep learning, in particular Convolutional Neural Networks (CNNs), have indicated excellent promise in overcoming these limitations in being capable of learning data-driven, highly robust feature representations. This study proposes and compares an extensive denoising pipeline that unites CNNs with both classical and hybrid filters to improve the quality of MRI images. The pipeline encompasses not only independent classical filters but also new hybrid pipelines like NLM-Gaussian Fusion, NLM-Gaussian Sequential, and Wavelet-Anisotropic Diffusion (WAD), all enriched with deep CNNs. Experiments were performed using a publicly shared MRI dataset of 5141 training images and 1279 test images. Performance was gauged using Peak Signal-to-Noise Ratio (PSNR), Structural Similarity Index (SSIM), and Mean Squared Error (MSE). Results show that while the Wavelet filter performed best as a standalone denoising filter, when CNNs were integrated with hybrid filters, there were monumental improvements in all metrics tried, with the pipeline of NLM-Gaussian Fusion + CNN achieving a PSNR of 30.4 and SSIM of 0.65. Moreover, visualizations such as SSIM heatmaps and loss-epoch convergence plots supported the efficacy of the proposed models in preserving structural information. The study reveals that the use of CNNs with conventional and hybrid filters offers synergistic benefits, especially for low-resource clinical setups where denoising quality is paramount. The novelty in this research comes from its systematic benchmarking of traditional as well as hybrid filtering pipelines supplemented with CNNs, providing empirical evidence for their utility in real-world medical imaging scenarios. These findings not only contribute to the widening ambit of AI-assisted image reconstruction but also provide functional avenues towards enhancing the dependability of diagnosis in resource-scarce healthcare environments.