Kernel Sparse Models for Automated Tumor Segmentation

TL;DR

This paper introduces kernel sparse coding methods for automated and user-initialized tumor segmentation in MR images, leveraging high-dimensional feature spaces and expert-labeled training data to improve accuracy.

Contribution

It presents novel kernel sparse coding algorithms for tumor segmentation that do not require manual initialization, enhancing automation and accuracy in medical image analysis.

Findings

Automated method achieves high accuracy in tumor detection.

User-initialized approach offers low complexity segmentation.

Validated against expert manual segmentation with positive results.

Abstract

In this paper, we propose sparse coding-based approaches for segmentation of tumor regions from MR images. Sparse coding with data-adapted dictionaries has been successfully employed in several image recovery and vision problems. The proposed approaches obtain sparse codes for each pixel in brain magnetic resonance images considering their intensity values and location information. Since it is trivial to obtain pixel-wise sparse codes, and combining multiple features in the sparse coding setup is not straightforward, we propose to perform sparse coding in a high-dimensional feature space where non-linear similarities can be effectively modeled. We use the training data from expert-segmented images to obtain kernel dictionaries with the kernel K-lines clustering procedure. For a test image, sparse codes are computed with these kernel dictionaries, and they are used to identify the tumor regions. This approach is completely automated, and does not require user intervention to initialize the tumor regions in a test image. Furthermore, a low complexity segmentation approach based on kernel sparse codes, which allows the user to initialize the tumor region, is also presented. Results obtained with both the proposed approaches are validated against manual segmentation by an expert radiologist, and the proposed methods lead to accurate tumor identification.