Reducing inter scanner variability using Voxel-based relaxometry and Z-score normalization: 6 years Longitudinal Study of Hip-OA patients

Motivation: It is important to examine and correct inter-scanner variability of T1rho/T2 values to improve the accuracy of longitudinal studiesGoal(s): To evaluate the inter-scanner variability of T1rho/T2 values and measure longitudinal changes in hip cartilage T1rho/T2 values after calibration. Approach: TCalibrate the hip cartilage T1rho/T2 values using Voxel-based relaxometry and Z-score normalization techniquesResults: The T1rho/T2 values showed that there was no statistically significant cartilage region (p<0.05) between the scanners. The longitudinal results showed an increase in number of subjects showing positive slope was increased in T1rho/T2 values after calibration (36.84 and 34.21%) compared without calibration (15.8% for both T1rho/T2). Impact: The technique used for reducing the inter-scanner variability of T1rho/T2 values may benefit the longitudinal assessments of hip OA, specifically for evaluating disease progression over time on different scanners/before and after scanner upgrades