2018 Volume 64 Issue Suppl.1 Pages 136-137
Background: Texture analysis derives a general, efficient and compact quantitative description of textures. Gray Level Co-occurrence Matrix (GLCM) method was developed by Haralick et al. (IEEE 1973), in which contrast of the textural parameter and entropy means the local change of the image contrast and the property opposite to homogeneity, retrospectively. GLCM is calculated using pixel offset (usually 1 pixel) and four directions (0°, 90°, 45°, 135°).
Purpose: To validate the usefulness of the texture analysis of T2 image of medial meniscus by examining the relationship between textural feature of medial meniscus and medial meniscal pathologies, such as the structural changes and displacement.
Methods: 307 knees of 307 subjects who enrolled the ongoing population-based cohort study in our university (72.95±5.47 years of age, M: 128 / F: 179) were analyzed. The written informed consent was obtained from all participants. The Proton Density Weight Image (PDWI) without FS and Multi Slice Multi Echo (MSME) images of the knee joints were obtained by 0.3 Tesla MRI system. T2 map was reconstructed using MSME images. Osteoarthritis (OA) changes of the knee joint of the subjects were evaluated using the Kellgren-Lawrence (K/L) grades on radiography and the Whole-Organ Magnetic Resonance Imaging Score (WORMS) on MRI. The medial meniscal extrusion (MME) was measured on a T2 image and a T2 map. Texture analysis of medial meniscus by GLCM method was performed for T2 image. Association between these factors were assessed using Spearman’s correlation test or Kruskal-Wallis verification with an in-house program created with Matlab 2017a (MathWorks, Natick, MA, USA).
Results: The MME was associated with the K/L grades (p<0.001) and WORMS scores of medial meniscus (r=0.23, p<0.001) of the subjects, respectively. Among the texture parameters of the medial meniscus, 90° of the contract of the medial meniscus was negatively associated with the MME (R2=0.20, p<0.001), while variance of the medial meniscus was positively associated with the MME (R2=0.24, p<0.001). The entropy of the menial meniscus was associated with the contrasts (0°, R2=0.27, p<0.001; 90°, R2=0.33, p<0.001) and the variance (R2=0.27, p<0.001) of the medial meniscus, retrospectively. While no association was observed between the entropy and MME (R2=0.05, p=0.39) and K/L grades (p=0.11), retrospectively, the contrasts (0°, R2=0.15, p<0.01; 90°, R2=0.16, p<0.01) of the medial meniscus were associated with the WORMS scores of medial meniscus of the subjects.
Discussion and Conclusion: MME was associated with the OA severities evaluated by K/L grades on radiography and WORMS on MRI, indicating that MME is one of the factors involved in the progression of the disease. As the association between textural features (contrast 0°, 90°) of the medial meniscus, variables are suggested to indicate the degeneration of the medial meniscus.
