Evaluation of Temporomandibular Joint Disc Displacement with Magnetic Resonance Imaging Based Radiomics Analysis.

Objectives: The purpose of this study was to propose a machine-learning model and assess its ability to classify temporomandibular joint (TMJ) disc displacements on magnetic resonance (MR) T1-weighted and PD-weighted images.

Methods: This retrospective cohort study included 180 TMJs from 90 patients with TMJ signs and symptoms. A Radiomics platform was used to extract imaging features of disc displacements. Thereafter, different machine learning algorithms and logistic regression were implemented on radiomic features for feature selection, classification, and prediction. The radiomic features included first-order statistic, size- and shape-based features and texture features. Six classifiers, including logistic regression, random forest, decision tree, k-nearest neighbors (KNN), XGBoost and support vector machine were used for a model building which could predict the TMJ disc displacements. The performance of models was evaluated by sensitivity, specificity and ROC curve.

Results: KNN classifier was found to be the most optimal machine learning model for prediction of TMJ disc displacements. The AUC, sensitivity, and specificity for the training set were 0.944, 0.771, 0.918 for normal, anterior disc displacement with reduction (ADDwR) and anterior disc displacement without reduction (ADDwoR) while testing set were 0.913, 0.716, 1 for normal, ADDwR and ADDwoR. For TMJ disc displacements, skewness, root mean squared, kurtosis, minumum, large area low gray level emphasis, gray level non-uniformity and long run high gray level emphasis, were selected as optimal features.

Conclusions: This study has proposed a machine learning model by KNN analysis on TMJ MR images, which can be used to TMJ disc displacements.