Combination of 3.0T magnetic resonance imaging T mapping with texture analysis for evaluating the degeneration of lumbar facet joints.

Objectives: Quantitative magnetic resonance imaging has been successfully applied to assess the status of cartilage biochemical components. This study aimed to investigate the performance of 3.0T magnetic resonance imaging T mapping combined with texture analysis for evaluating the early degeneration of lumbar facet joints.

Methods: A total of 38 patients (20 in the asymptomatic group and 18 in the symptomatic group) were enrolled. All patients underwent 3.0T magnetic resonance imaging conventional sequences, water excitation three-dimensional spoiled gradient echo sequence (3D-WATSc), and T mapping scans. The bilateral L and L/S lumbar facet joints were morphological graded using the Weishaupt criteria, T values, and texture parameters derived from T mapping of cartilage. The Kruskal-Wallis test was used to compare the differences of parameters among different groups. Multivariate logistic regression analysis was used to obtain the independent predictive factors for evaluating the early degeneration of lumbar facet joints. Receiver operating characteristic (ROC) curve was performed and the area under curve (AUC) was calculated. Spearman correlation analysis was used to evaluate the correlation of the independent predictors of cartilage T value and texture parameters with the subjects' Japanese Orthopedic Association (JOA) score or Visual Analogue Scale (VAS) score.

Results: A total of 148 facet joints were selected, including 70 in Weishaupt 0 (normal) group, 58 in Weishaupt 1 group, and 20 in Weishaupt 2-3 group. T value, entropy, and contrast increased significantly as the exacerbation of facet joint degeneration (all <0.05), while the inverse difference moment, energy, and correlation decreased (all <0.05). Entropy among different groups was significantly different (all <0.05), and the differences of T value, contrast, inverse difference moment, and energy between Weishaupt 0 and Weishaupt 1 groups, or Weishaupt 0 and Weishaupt 2-3 groups were statistically significant (all <0.05). Multivariate logistic regression analysis suggested that T value and inverse difference moment were the independent predictors for evaluating early degeneration of facet joints. The combination of T value with inverse difference moment achieved the best performance in distinguishing Weishaupt 0 from Weishaupt 1 (AUC=0.85), with sensitivity and specificity at 92.7% and 76.5%, respectively. In the symptom group, the cartilage T value combined inverse difference moment was positively correlated with JOA score (=0.475, <0.05) and VAS score (=0.452, <0.05).

Conclusions: 3.0T magnetic resonance imaging T mapping combined with texture analysis is helpful to quantitatively evaluate the early degeneration of lumbar facet joints, in which the T value and inverse difference moment show an indicative significance．.