The Impact of Different Regions of Interest on Shear Wave Elastography Assessment of the Meniscus in the Knee Joint

Rationale and objectives: To investigate the impact of different regions of interest (ROI) on the assessment of shear wave elastography (SWE) in evaluating the meniscus of the knee joint.

Materials and methods: After ethical approval, a total of 141 participants were enrolled in this prospective study from February to October 2023. SWE was utilized to evaluate the anterior horn of the lateral meniscus (LM) and medial meniscus (MM), using two different ROIs (ROI-Small and ROI-Trace) to measure the elastic mean value (Emean) and elastic maximum value (Emax). The differences in elasticity values between the normal menisci and torn menisci were compared, and the impact of different ROI selection methods on the diagnostic performance of elastic parameters in the torn menisci was assessed using receiver operating characteristic (ROC) curves.

Results: In Emean comparison, only MM in the tear group showed higher ROI-S than ROI-T. When comparing Emax, all ROI-T values were higher than the ROI-S values, and this difference was statistically significant. Different sizes of ROI did not significantly impact the diagnostic performance of Emean in LM and MM, nor the diagnostic effectiveness of Emax in LM. However, only the area under the curve (AUC) of MM for Emax in both ROI-S and ROI-T showed a statistically significant difference.

Conclusion: The shear wave elasticity values and diagnostic performance may vary depending on the ROI settings. Therefore, it is recommended to use a 2 mm diameter ROI placed at the central position of the meniscus, with Emean as the elasticity index.