Radiomics as a measure superior to the Dice similarity coefficient for tumor segmentation performance evaluation

Abstract

In high-quality radiotherapy delivery, precise segmentation of targets and healthy structures is essential. This study proposes Radiomics features as a superior measure for assessing the segmentation ability of physicians and auto-segmentation tools, in comparison to the widely used Dice Similarity Coefficient (DSC). The research involves selecting reproducible radiomics features for evaluating segmentation accuracy by analyzing radiomics data from 2 CT scans of 10 lung tumors, available in the RIDER Data Library. Radiomics features were extracted using PyRadiomics, with selection based on the Concordance Correlation Coefficient (CCC). Subsequently, CT images from 10 patients, each segmented by different physicians or auto-segmentation tools, were used to assess segmentation performance. The study reveals 206 radiomics features with a CCC greater than 0.93 between the two CT images, indicating robust reproducibility. Among these features, seven exhibit low Intraclass Correlation Coefficients (ICC), signifying increased sensitivity to segmentation differences. Notably, ICCs of original shape features, including sphericity, elongation, and flatness, ranged from 0.1177 to 0.995. In contrast, all DSC values exceeded 0.778. This research demonstrates that radiomics features, particularly those related to shape and energy, can capture subtle variations in tumor segmentation characteristics, unlike DSC. As a result, Radiomics features with ICC prove superior for evaluating a physician's tumor segmentation ability and the performance of auto-segmentation tools. The findings suggest that these new metrics can be employed to assess novel auto-segmentation methods and enhance the training of individuals in medical segmentation, thus contributing to improved radiotherapy practices.