V. Juras (Vienna, AT)
Medical University of Vienna High Field MR Centre, Department of Biomedical Imaging and Image-Guided TherapyPresenter Of 1 Presentation
18.4.9 - A novel radiological texture analysis technique for the assessment of cartilage regeneration following GelrinC treatment
Abstract
Purpose
To evaluate the quality of regenerated cartilage tissue and maturation trend after GelrinC, a hydrogel cartilage repair procedure, using T2 MRI and texture analysis of T2 maps.
Methods and Materials
T2 maps were constructed from multi-echo spin-echo 1.5/3 MR scans and used for Global T2 index calculation and Texture analysis (grey-level co-occurrence matrix, GLCM).
GLCM analysis was performed on MR scans obtained from fourteen patients, for whom data was available at 18 as well as at 24 months following GelrinC procedure. GLCM texture features, including autocorrelation, contrast, correlation, entropy, dissimilarity and homogeneity were calculated for repaired and native cartilage using selected ROIs of T2 maps.
Global T2 index was calculated as a ratio between global T2 of repaired cartilage and native cartilage at 18 and 24 months following GelrinC implantation respectively.
Differences between repaired and native cartilage for GLCM features and T2 values were calculated using a paired t-test at the 0.05 significance level.
Results
Global T2 index values ranging between 0.8 and 1.2 represent healthy cartilage whereas values <0.8 and >1.2 represent fibrotic and disorganized cartilage respectively. The mean global T2 index values at 18 and 24 months were 1.04±0.25 (n=22) and 1.05±0.24 (n=25) respectively, reflecting healthy cartilage.
The 'Autocorrelation' GLCM feature, a measure for cartilage layering, showed significantly different means at 18 and 24 months suggesting development of native stratification of the regenerated tissue. Moreover, the 'Homogeneity' which is a measure of T2 variation significantly increased between 18 and 24 months, reflecting increased smoothness of the regenerated tissue (Figure 1).
Conclusion
The texture analyses in conjunction with global T2 values further demonstrates the maturation and organization of the newly regenerated cartilage following GelrinC implantation. Furthermore, the results show that GLCM is a novel and robust method to assess the structure of the repaired cartilage.