Evaluation of articular cartilage with quantitative MRI in an equine model of post‐traumatic osteoarthritis

Abstract

Chondral lesions lead to degenerative changes in the surrounding cartilage tissue, increasing the risk of developing post-traumatic osteoarthritis (PTOA). This study aimed to investigate the feasibility of quantitative magnetic resonance imaging (qMRI) for evaluation of articular cartilage in PTOA. Articular explants containing surgically induced and repaired chondral lesions were obtained from the stifle joints of seven Shetland ponies (14 samples). Three age-matched nonoperated ponies served as controls (six samples). The samples were imaged at 9.4 T. The measured qMRI parameters included T 1 , T 2 , continuous-wave T 1ρ (CWT 1ρ), adiabatic T 1ρ (AdT 1ρ), and T 2ρ (AdT 2ρ) and relaxation along a fictitious field (T RAFF). For reference, cartilage equilibrium and dynamic moduli, proteoglycan content and collagen fiber orientation were determined. Mean values and profiles from full-thickness cartilage regions of interest, at increasing distances from the lesions, were used to compare experimental against control and to correlate qMRI with the references. Significant alterations were detected by qMRI parameters, including prolonged T 1 , CWT 1ρ , and AdT 1ρ in the regions adjacent to the lesions. The changes were confirmed by the reference methods. CWT 1ρ was more strongly associated with the reference measurements and prolonged in the affected regions at lower spin-locking amplitudes. Moderate to strong correlations were found between all qMRI parameters and the reference parameters (ρ = −0.531 to −0.757). T 1 , low spin-lock amplitude CWT 1ρ , and AdT 1ρ were most responsive to changes in visually intact cartilage adjacent to the lesions. In the context of PTOA, these findings highlight the potential of T 1 , CWT 1ρ , and AdT 1ρ in evaluation of compositional and structural changes in cartilage.

Machine Learning Prediction of Collagen Fiber Orientation and Proteoglycan Content From Multiparametric Quantitative MRI in Articular Cartilage

“…Tissue samples were positioned in the scanner such that the main magnetic field was approximately perpendicular to the normal of the bone–cartilage interface to minimize the magic angle effect. A single slice was selected, as detailed in the literature, 25 covering a predefined marked regions on each specimen. The MRI protocol consisted of a single‐slice fast spin echo (FSE) coupled with six different magnetization preparations including T 1 with six TIs between 0.2 and 3 seconds, T 2 with seven TEs between 8.7 and 80 msec, continuous‐wave T 1 ρ (CW T 1 ρ ) with seven spin lock times (TSLs) between 0 and 128 msec, 26 adiabatic T 1 ρ (Ad T 1 ρ ), Ad T 2 ρ , 27 and relaxation along a fictitious field ( T RAFF ) consisted of five different pulse trains incremented from 0 to 16 pulses with pulse duration 9 msec 28 .…”

“…25,29 In brief, the samples were formalin-fixed, decalcified, and sectioned to include the indentation test locations and the sites of the MRI defined ROIs. 25,29 The staining of sections was done using Safranin-O to measure PG content via optical density. 24,30 DD analysis was carried out using a light microscope (Nikon Microphot-FXA, Nikon Co., Tokyo, Japan) equipped with a monochromatic light source and 12-bit CCD camera (ORCA-ER, Hamamatsu Photonics, K.K., Hamamatsu, Japan).…”

Osteoarthritis: a common disease that should be avoided in the athletic horse’s life

“…In addition to morphological evaluation, the development of quantitative MRI techniques has allowed the identification of biochemical and biomechanical changes in cartilage, allowing the diagnosis of early degenerative conditions that precede morphological changes ( Nelson et al, 2018 ). Extracellular matrix components such as glycosaminoglycans, collagen, and water are usually highlighted in these techniques, which have shown promising results in detecting early changes in OA ( Kajabi et al, 2021 ).…”

Embedded Quantitative MRI T1ρ Mapping Using Non-Linear Primal-Dual Proximal Splitting

“…Generally, spin-lock pulses operate at and are limited to frequencies that correspond to slow molecular processes that are often both biologically important and altered in disease-related changes. The T relaxation time has been reported as a promising biomarker for numerous tissues and diseases, such as different disorders of the brain [ 3 , 4 ], cardiomyopathy [ 5 ], liver fibrosis [ 6 ], musculoskeletal disorders [ 2 , 7 , 8 ] and many others. For a broader overview of T relaxation and its applications, the reader is referred to the reviews by Gilani and Sepponen [ 1 ], Wang and Regatte [ 7 ] and Borthakur et al [ 2 ].…”