Correlation of magnetic resonance imaging–based knee cartilage T2 measurements and focal knee lesions with body mass index: Thirty‐six–month followup data from a longitudinal, observational multicenter study

Abstract

Objective To compare MRI-based knee cartilage T2 measurements and focal knee lesions and 36 month changes in these parameters, among knees of normal controls and knees of normal-weight, overweight, and obese subjects with risk factors for knee osteoarthritis (OA). Methods 267 subjects aged 45–55 years from the Osteoarthritis Initiative (OAI) database were analysed in this study. 231 subjects had risk factors for knee OA, but no radiographic OA (KL-score≤1) at baseline. 36 subjects were normal controls. Subjects with OA risk factors were stratified in three groups: normal weight (n=78), overweight (n=84), and obese (n=69). All subjects underwent 3T MRI of the right knee at baseline and after 36 months. Focal knee lesions were assessed and cartilage T2 measurements (mean T2 and T2 texture analysis) were performed. Results The baseline prevalence and severity of meniscal and cartilage lesions were highest in obese subjects and lowest in normal controls (p<0.05). Obese subjects had the highest mean T2 values and the most heterogeneous cartilage (as assessed by T2 texture analysis), while normal controls had the lowest mean T2 values and the most homogeneous cartilage at baseline (p<0.05). Increased BMI was significantly (p<0.05) associated with greater progression of cartilage lesions and constantly elevated cartilage T2 entropy over 36 months. Conclusion In pre-clinical OA, increased BMI is associated with more severe cartilage degeneration as assessed by both morphological and quantitative MRI measurements.

Physical Activity and Spatial Differences in Medial Knee T1rho and T2 Relaxation Times in Knee Osteoarthritis

“…16,17,49 Data from the OAI show that in asymptomatic adults and those with OA risk factors, obese individuals had the highest T2 values and normal-weight individuals had the lowest mean T2 values. 4 In cohorts of less than 30 individuals, people with medial knee OA who had varus alignment were found to have higher cartilage T1rho and T2 than those with valgus alignment. 20,55 Most of these studies either were in healthy cohorts or had a small sample size.…”

Subregional laminar cartilage MR spin–spin relaxation times (T2) in osteoarthritic knees with and without medial femorotibial cartilage loss – data from the Osteoarthritis Initiative (OAI)

“…Possible explanations for this discrepancy include the differences in study designs (cohort studies vs. matched case-control study), different inclusion criteria (knees with and/or without radiographic OA 2,9,10 vs. knees with established radiographic OA [KLG 2/3]), and different definitions of progression (incidence or worsening of semi-quantitative cartilage lesion scores vs. loss in both MRI-based cartilage thickness and radiographic JSW in the medial femorotibial compartment). To avoid potential bias from disease-related covariates such as BMI 20,21 , the presence or absence of radiographic OA 14,15 , or pain 19 , a matched case-control design controlling for these factors was chosen for the current study. It is of note that a sensitivity analysis in the study by Prasad et al 10 found the association with progressor status to disappear, once knees with and without definite radiographic knee OA were analyzed separately, which accords with the findings in the current study.…”

Response of knee cartilage T1rho and T2 relaxation times to in vivo mechanical loading in individuals with and without knee osteoarthritis

“…[17–18] Age and BMI were included because these variables were significantly different between the groups and are known to be related to cartilage MR relaxation times. [19–20] Gender was included because prevalence of knee OA is higher in women than men. The GEE model was first run with the interaction between group (Control vs. OA) and Condition (repeated measure).…”