Acquisition repeatability of MRI radiomics features in the head and neck: a dual-3D-sequence multi-scan study

Abstract

Radiomics has increasingly been investigated as a potential biomarker in quantitative imaging to facilitate personalized diagnosis and treatment of head and neck cancer (HNC), a group of malignancies associated with high heterogeneity. However, the feature reliability of radiomics is a major obstacle to its broad validity and generality in application to the highly heterogeneous head and neck (HN) tissues. In particular, feature repeatability of radiomics in magnetic resonance imaging (MRI) acquisition, which is considered a crucial confounding factor of radiomics feature reliability, is still sparsely investigated. This study prospectively investigated the acquisition repeatability of 93 MRI radiomics features in ten HN tissues of 15 healthy volunteers, aiming for potential magnetic resonance-guided radiotherapy (MRgRT) treatment of HNC. Each subject underwent four MRI acquisitions with MRgRT treatment position and immobilization using two pulse sequences of 3D T1-weighed turbo spin-echo and 3D T2-weighed turbo spin-echo on a 1.5 T MRI simulator. The repeatability of radiomics feature acquisition was evaluated in terms of the intraclass correlation coefficient (ICC), whereas within-subject acquisition variability was evaluated in terms of the coefficient of variation (CV). The results showed that MRI radiomics features exhibited heterogeneous acquisition variability and uncertainty dependent on feature types, tissues, and pulse sequences. Only a small fraction of features showed excellent acquisition repeatability (ICC > 0.9) and low within-subject variability. Multiple MRI scans improved the accuracy and confidence of the identification of reliable features concerning MRI acquisition compared to simple test-retest repeated scans. This study contributes to the literature on the reliability of radiomics features with respect to MRI acquisition and the selection of reliable radiomics features for use in modeling in future HNC MRgRT applications.

Keywords: Head and neck; Intraclass correlation coefficient; Magnetic resonance guided radiotherapy; Radiomics; Repeatability.

Fig. 1

Subject positional verification setup and the acquired 3D TSE MR images. (a) A subject immobilized using thermoplastic mask aligned with the external laser system; (b) a subject setup and the coil setting on the MR-sim; (c) all ten VOIs on MRI image

Fig. 2

Boxplots of ICC values in different tissue VOIs for both pulse sequences

Fig. 3

Boxplots of ICC values for different radiomics feature categories in all VOIs for both pulse sequences

Fig. 4

Percentages of excellent, good, moderate, and poor ICCs of radiomics features in different tissue VOIs for (a) 3D-T1W-TSE and (b) 3D-T2W-TSE pulse sequences

Fig. 5

Acquisition repeatability of radiomics features for each VOI and pulse sequence. Excellent (ICC > 0.9), good (0.9 > ICC > 0.75), moderate (0.75 > ICC > 0.5), and poor (ICC < 0.5) repeatability was marked by green, yellow, red, and black blocks respectively

Fig. 6

The heatmaps depicting CV_{intra-subject} values of all radiomics features in different VOIs for 3D-T1W-TSE and 3D-T2W-TSE pulse sequences

Fig. 7

Boxplots of the feature CV_{intra-subject} values in different tissue VOIs for both pulse sequences