Radiomics analysis of unaffected side changes in classic trigeminal neuralgia

To investigate the subtle differences in the structure of the unaffected trigeminal nerve between patients with classic trigeminal neuralgia (CTN) and healthy controls (HCs) by means of radiomics, so as to further explore the etiological mechanism of trigeminal neuralgia (TN).

The imagine data of 95 CTN patients and 89 matched HCs were collected and retrospectively analyzed. They were assigned to four groups according to the presence or absence of neurovascular compression (NVC) of the unaffected trigeminal nerve (HCs with and without NVC; CTN patients with and without NVC on the unaffected side). All patients underwent magnetic resonance imaging (MRI) scans. Bilateral trigeminal cisternal segments were manually delineated, followed by feature extraction, dimensionality reduction, feature selection, model construction and model evaluation.

Six weighted textural signatures (sphericity, maximum 2D diameter, skewness, robust mean absolute deviation, large dependence low gray level emphasis, and surface-to-volume ratio) were found in HCs with and without NVC, while 7 were found in CTN patients without NVC on the unaffected side and HCs without NVC. The Rad_score was statistically different between the two groups (P < 0.05). The AUC of the training set was consistent with that of the validation set. The calibration curves of the training and validation sets demonstrated the high accuracy of the model.

NVC can alter trigeminal nerve structure and cause alterations in related characteristics; but NVC is not a necessary condition for the formation of CTN, and its incidence is also high in asymptomatic healthy people, and thus it is necessary to grade the severity of NVC. In addition, there are differences in the characteristics of the unaffected side between CTN patients and HCs, which may be due to congenital or secondary factors.