Longitudinal study using voxel-based relaxometry: Association between cartilage T1ρand T2and patient reported outcome changes in hip osteoarthritis.
To study the local distribution of hip cartilage T1ρand T2relaxation times and their association with changes in patient reported outcome measures (PROMs) using a fully automatic, local, and unbiased method in subjects with and without hip osteoarthritis (OA).



The 3 Tesla MRI studies of the hip were obtained for 37 healthy controls and 16 subjects with radiographic hip OA. The imaging protocol included a three-dimensional (3D) SPGR sequence and a combined 3D T1ρand T2sequence. Quantitative cartilage analysis was compared between a traditional region of interest (ROI)-based method and a fully automatic voxel-based relaxometry (VBR) method. Additionally, VBR was used to assess local T1ρand T2differences between subjects with and without OA, and to evaluate the association between T1ρand T2and 18-month changes PROMs.



Results for the two methods were consistent in the acetabular (R = 0.79; coefficients of variation [CV] = 2.9%) and femoral cartilage (R = 0.90; CV = 2.6%). VBR revealed local patterns of T1ρand T2elevation in OA subjects, particularly in the posterosuperior acetabular cartilage (T1ρ: P = 0.02; T2: P = 0.038). Overall, higher T1ρand T2values at baseline, particularly in the anterosuperior acetabular cartilage (T1ρ: Rho = -0.42; P = 0.002; T2: Rho = -0.44; P = 0.002), were associated with worsening PROMS at 18-month follow-up.



VBR is an accurate and robust method for quantitative MRI analysis in hip cartilage. VBR showed the capability to detect local variations in T1ρand T2values in subjects with and without osteoarthritis, and voxel based correlations demonstrated a regional dependence between baseline T1ρand T2values and changes in PROMs.



1 J. MAGN. RESON. IMAGING 2017;45:1523-1533.
Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA.
Valentina
V
Pedoia
Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA.
Matthew C
MC
Gallo
Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA.|Department of Physical Therapy and Rehabilitation Science, University of California San Francisco, San Francisco, California, USA.
Richard B
RB
Souza
Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, California, USA.
Sharmila
S
Majumdar
D000328:Adult; D000368:Aged; D001331:Automation; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000473:pathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging* / Q000473:pathology*; D000071066:Patient Reported Outcome Measures; D016059:Range of Motion, Articular
T1ρ; T2; atlas-based segmentation; hip cartilage; osteoarthritis; voxel-based relaxometry