The application values of MR quantitative susceptibility mapping in differentiation between knee meniscus degeneration and tear / 中华放射学杂志

ABSTRACT

Objective:To evaluate the feasibility and the application values of quantitative susceptibility mapping (QSM) for the assessment of meniscal injury and in distinguishing meniscus degeneration and tears.Methods:The clinical and imaging data of 70 patients suspected of meniscus injury and scheduled for arthroscopy in Shandong Medical Imaging Research Institute, Cheeloo College of Medicine, Shandong University from November 2019 to June 2020 were analyzed retrospectively. Thirty age-and sex-matched healthy subjects were also examined as controls. All subjects received knee joint QSM and routine MR imaging. According to the results of arthroscopy, the patients was divided into meniscus degeneration and meniscus tear groups, respectively. The conventional MR was evaluated by two radiologists. The meniscus injury area was delineated on the original QSM magnitude images (the central area of the posterior corner of the lateral meniscus was selected in the healthy controls) and mapped to the corresponding QSM maps, and the magnetic susceptibility values were measured. Kruskal-Wallis H test was used to analyze the magnetic sensitivity values of meniscal degeneration, meniscal tear and healthy control groups; and Bonferroni was used to correct the pairwise comparison. ROC curve was established to evaluate the threshold and efficacy of magnetic susceptibility value in the diagnosis of meniscal tear. The results were compared with those of conventional MRI. Results:The magnetic susceptibility values of meniscus of healthy controls, meniscal degeneration and meniscal tear groups were (0.035±0.016)ppm, -0.031(-0.040,-0.005)ppm, and(-0.122±0.115)ppm, respectively, with significant difference found among the three groups (χ2=44.419, P<0.05). The magnetic susceptibility values of meniscus of healthy controls was significantly higher than those of meniscus degeneration patients and meniscus tear patients (χ2=-23.843, -48.253, P<0.05). The magnetic susceptibility values of meniscus of meniscus tear group was significant lower than those of meniscus degeneration group (χ2=-24.410, P<0.05). Taking magnetic susceptibility values of -0.062 5 ppm as threshold, the area under the ROC curve for the diagnosis of meniscal tears was 0.949, with the sensitivity as 87% and the specificity as 100%. The sensitivity and specificity of conventional MRI in the diagnosis of meniscal tears were 86.8% and 87.5%, respectively. Conclusion:QSM can quantitatively evaluate meniscus injury and can be used as an effective supplement method to conventional MRI, which is helpful to improve the diagnosis of meniscus tear.