The effects of acute loading on T1rho and T2 relaxation times of tibiofemoral articular cartilage

详细信息    查看全文

• 作者：R.B. Souza ; C. Stehling ; B.T. Wyman ; M.-P. Hellio Le Graver ; X. Li ; T.M. Link ; S. Majumdar
• 关键词：Magnetic resonance imaging ; T1rho ; T2 ; Acute loading ; Osteoarthritis ; Cartilage
• 刊名：Osteoarthritis and Cartilage
• 出版年：2010
• 出版时间：December 2010
• 年：2010
• 卷：18
• 期：12
• 页码：1557-1563
• 全文大小：506 K

文摘

Summary

Objective

To evaluate the effect of acute loading on healthy and osteoarthritic knee cartilage T_1ρ and T₂ relaxation times.

Design

Twenty subjects with radiographic evidence of osteoarthritis (OA) and 10 age-matched controls were enrolled. Magnetic resonance imaging (MRI) acquisition, including T_1ρ and T₂ map sequences were performed unloaded and loaded at 50 % body mass. Cartilage masks were segmented semi-automatically on registered high-resolution spoiled gradient-echo (SPGR) images for each compartment (medial and lateral). Cartilage lesions were identified using a modified Whole Organ Magnetic Resonance Imaging Score (WORMS) score. Statistical differences were explored using separate two-way (group × loading condition) Analysis of Variance (ANOVA) using age as a covariate to evaluate the effects of loading on T_1ρ and T₂ relaxation times.

Results

A significant decrease in T_1ρ (44.5 ± 3.8 vs 40.2 ± 4.8 ms for unloaded and loaded, respectively; P < 0.001) and T₂ (31.8 ± 3.8 vs 30.5 ± 4.8 ms for unloaded and loaded, respectively; P < 0.001) relaxation times was observed in the medial compartment with loading while no differences were observed in the lateral compartment. This behavior occurred independent of WORMS score. Cartilage compartments with small focal lesions experienced greater T_1ρ change scores with loading when compared to cartilage without lesions or cartilage with larger defects (P = 0.05).

Conclusions

Acute loading resulted in a significant decrease in T_1ρ and T₂ relaxation times of the medial compartment, with greater change scores observed in cartilage regions with small focal lesions. These data suggest that changes of T_1ρ values with loading may be related to cartilage biomechanical properties (i.e., tissue elasticity) and may be a valuable tool for the scientist and clinician at identifying early cartilage disease.