Association of cartilage [Formula: see text] and [Formula: see text] relaxation time measurement with hip osteoarthritis progression: A 5-year longitudinal study using voxel-based relaxometry and Z-score normalization

Rafeek Thahakoya; Koren E Roach; Misung Han; Rupsa Bhattacharjee; Fei Jiang; Johanna Luitjens; Emma Bahroos; Valentina Pedoia; Richard B Souza; Sharmila Majumdar

doi:10.1016/j.ocarto.2024.100538

Association of cartilage $T_{1 ρ}$ and $T_{2}$ relaxation time measurement with hip osteoarthritis progression: A 5-year longitudinal study using voxel-based relaxometry and Z-score normalization

Osteoarthr Cartil Open. 2024 Oct 28;6(4):100538. doi: 10.1016/j.ocarto.2024.100538. eCollection 2024 Dec.

Authors

Rafeek Thahakoya¹, Koren E Roach^{1

2

3

4}, Misung Han¹, Rupsa Bhattacharjee¹, Fei Jiang⁵, Johanna Luitjens¹, Emma Bahroos¹, Valentina Pedoia¹, Richard B Souza^{1

6}, Sharmila Majumdar¹

Affiliations

¹ Department of Radiology and Biomedical Imaging, University of California San Francisco, CA, USA.
² Department of Biomedical Engineering, Schulich School of Engineering, University of Calgary, Calgary, Alberta, Canada.
³ Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
⁴ McCaig Institute for Bone and Joint Health, Cumming School of Medicine, Calgary, Alberta, Canada.
⁵ Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA, USA.
⁶ Department of Physical Therapy and Rehabilitation Science, University of California San Francisco, San Francisco, CA, USA.

Abstract

Objective: To study the longitudinal changes of cartilage $T_{1 ρ}$ and $T_{2}$ relaxation time measurements in hip-OA patients.

Methods: A calibration study compared two scanner data, Scanner-1 (GE Discovery MR750 3.0T) with unilateral acquisition protocol and Scanner-2 (GE Signa Premier 3.0T) with bilateral acquisition protocol, using nine subjects(average age = 40.33 ± 13.53 years, 5 females), including one hip-OA subject. Quantified parameters from the Scanner-2 were adjusted using voxel-based relaxometry(VBR) and Z-score normalization to reduce the inter-scanner variability. Eighteen hip-OA Subjects (age = 53.11 ± 14.96 years, 12 females) were recruited to the longitudinal variability study from 2016, comprising five assessments at 1-year intervals. Baseline to 3rd-year data used unilateral acquisition with Scanner-1, while 4th-year data used bilateral acquisition with Scanner-2. A linear mixed-effects model(LME) assessed trajectory analyses, with acquisition year, age, sex, body mass index(BMI), and Kellgren-Lawrence(KL) score as predictor variables and cartilage mean $T_{1 ρ}$ and $T_{2}$ values as outcomes.

Results: VBR analysis after Z-score normalization showed that only a few of the whole cartilage voxels had significant differences in $T_{1 ρ} ($ femur-2.36 % and acetabular-3.23 %) and $T_{2}$ (femur-2.30 % and acetabular-2.94 %) values between the scanners. The LME analysis showed that the BMI predictor variable was significantly correlated with the femur $T_{1 ρ}$ (p < 0.0001) and $T_{2}$ (p < 0.0001) and acetabular $T_{1 ρ}$ (p < 0.0001) and $T_{2}$ (p < 0.0001) cartilage region.

Conclusion: The calibration study demonstrated the effectiveness of VBR and Z-score normalization in reducing inter-scanner variability. The longitudinal study revealed a significant correlation between $T_{1 ρ}$ and $T_{2}$ values of the cartilage and BMI; also the $T_{1 ρ}$ and $T_{2}$ values increased over time in some of the cartilage subregions.

Keywords: Articular cartilage; Hip osteoarthritis; Longitudinal study; VBR analysis.