[Quantitative study of supraspinatus tendon injury grading based on synthetic magnetic resonance imaging]

Objective: To investigate the diagnostic value of quantitative parameters of synthetic magnetic resonance imaging (SyMRI) in the grade of supraspinatus tendon injury. Methods: Ninety-seven patients with clinical definite of supraspinatus tendon injury from July 2021 to July 2022 in General Hospital of Ningxia Medical University were prospectively collected (case group), including 54 males and 43 females, with an age of 29 to 56 (37.4±9.6) years. According to the results of shoulder arthroscopy, the case group were divided into three subgroups included tendinopathy group (37 cases, grade Ⅱ), partial tear group (34 cases, grade Ⅲ) and complete tear group (26 cases, grade Ⅳ). During the same period, 28 normal rotator cuff volunteers without supraspinatus tendon injury were recruited (control group), including 16 males and 12 females, aged 23 to 49 (36.1±7.2) years, and marked as grade Ⅰ. All the subjects underwent MRI scan of articulatio humeri included T₁-weighted imaging(T₁WI) fast spin echo(FSE) sequences in axial view, T₂-weighted imaging(T₂WI) fat suppression(FS) sequences in axial view, T₂WI FS sequences in oblique coronal view, proton density-weighted (PDW) imaging in oblique sagittal view and SyMRI in oblique coronal view. The supraspinatus tendon was divided into lateral, medial and middle subregions according to its shape in oblique coronal T₂WI view, two radiologists measured the T₁, T₂ and PD values of the supraspinatus tendon. The interclass correlation coefficient (ICC) were used to compare the consistency between and within observers. One-way analysis of variance or Kruskal-Wallis H test were used to compare the differences of quantitative parameters in different grades, the multivariate logistic regression model was used to analyze the risk factors of supraspinatus tendon injury grade, and the receiver operating characteristic (ROC) curves and area under curve (AUC) was drawn and calculated to evaluate the diagnostic efficacy. The Spearman correlation was used to analyze the correlation between the quantitative values and grades of supraspinatus tendon injury. Results: The ICC values of T₁, T₂ and PD values for the three subregions of the supraspinatus tendon were greater than 0. 700. The differences of T₁ values in the lateral subregion, T₂ values in the lateral and middle subregions were statistically significant in the overall comparison across different grades (all P<0. 001).The differences of T₁ values in the middle and medial subregions, T₂ values in the medial subregion and PD values in the lateral, middle and medial subregions were not statistically significant in the overall comparison of different grades (all P>0. 05). Multiple logistic regression model analysis showed that T₂ values in the lateral and middle subregions were related factors for the grade of supraspinatus tendon injury[ OR (95%CI):1.123 (1.037-1.216), 0.122 (1.151-1.197);all P<0.001 ]. The AUC of the T₂ values in lateral subregion diagnosing grade Ⅰ vs grade Ⅳ, grade Ⅱ vs grade Ⅳ and grade Ⅲ vs grade Ⅳ were 0.891(95%CI: 0.801-0.981), 0.797(95%CI: 0.680-0.914), 0.723(95%CI: 0.594-0.853) (all P<0.001), and the AUC of the T₂ values in middle subregion diagnosing grade Ⅰ vs Ⅳ, grade Ⅱ vs Ⅳ, grade Ⅱ vs Ⅲ, and grade Ⅰ vs Ⅲ were 0.946 (95%CI: 0.849-0.989), 0.886 (95%CI: 0.809-0.962), 0.746 (95%CI: 0.631-0.861), 0.843 (95%CI: 0.745-0.941)(all P<0.001). The T₂ values in the lateral and middle subregions were positively correlated with the grade of supraspinatus tendon injury (r=0.542, 0.615; both P<0.001), while T₁ values and T₂ values in the medial subregions were not significantly correlated with the grade of supraspinatus tendon injury (both P>0.05). Conclusion: SyMRI has high clinical application value in the grading of supraspinatus tendon injury, especially T₂ value can be used as an effective quantitative parameter for the grading of supraspinatus tendon injury.