Assessment of Articular Cartilage and Subchondral Bone: Subtle and Progressive Changes in Experimental Osteoarthritis Using 50 MHz Echography In Vitro

Abstract

The main objectives of this work were to demonstrate the potential of 50 MHz echography for assessing initial and progressive morphological and structural changes of articular cartilage and bone developed in an experimental model of osteoarthritis (OA). Degenerative lesions were induced in rat knees by the unilateral intra-articular injection of a 3 mg dose of mono-iodo-acetic acid. To assess the lesion progression, the animals (n ‫؍‬ 30) were sacrificed at different time intervals up to 8 weeks after the injection. Three-dimensional echographic data were acquired in vitro on patellar cartilage and bone at various stages of the remodeling process using a scanning ultrasound microscope. Changes involving the OA cartilage characteristics are discussed relative to those of the contralateral control joint which received a placebo. Images of control cartilage showed a smooth hyperechoic articular surface and an echoic matrix. The cartilage thickness was 266 ؎ 44 m (mean ؎ SD) in the central region of the tissue. The precision of ultrasonic thickness measurements was better than 1.3%. First changes in cartilage internal structure and subchondral bone appeared on ultrasound images 3 days after the injection and were even more evident by day 7. They resulted in a slight thinning of the cartilage, a 30% increase of its internal structure echogenicity, and the appearance of echoic zones in subchondral bone. Histologic findings confirmed chondrocyte depletion and degeneration, decrease of matrix proteoglycans, and fibrovascular connective tissue proliferation at the subchondral plate. Progressive and severe lesions at both bone and cartilage surface and internal structure were assessed and correlated to histologic features. These results show that high resolution echography is sensitive to subtle and progressive osteochondral remodeling. This technique has the potential to be used for intra-articular quantitative imaging and assessment of early changes in bone and cartilage structure associated with natural human

Effects of antiinflammatory drugs on arthritic cartilage: A high‐frequency quantitative ultrasound study in rats

“…Recent research suggests that high-frequency US may also serve ex vivo as a useful means for the investigation of cartilage matrix structural changes occurring under var-ious experimental and clinical conditions (e.g., in the growth process and in osteoarthritis) (9)(10)(11)(12). In particular, our group has shown that 50 MHz US backscatter from cartilage matrix is not sensitive to changes in PG content, but is related to collagen network organization (13).…”

Imaging the joint in osteoarthritis: a place for ultrasound?

“…Initial findings are represented by blurring of the edges, which become irregular and lose their normal sharpness [1,11,17]. Firstly, they involve the superficial cartilaginous margin and correspond to the micro-cleft formation due to tissue deterioration [49]. Later, changes in the echotexture appear, with evidence of loss of homogeneity and transparency [22,[49][50][51][52][53].…”

“…Firstly, they involve the superficial cartilaginous margin and correspond to the micro-cleft formation due to tissue deterioration [49]. Later, changes in the echotexture appear, with evidence of loss of homogeneity and transparency [22,[49][50][51][52][53]. With disease progression, focal and asymmetric narrowing is usually present; subsequently, diffuse thinning is charted, up to the complete absence of the cartilaginous layer that corresponds to cartilage breakdown and bony denudation [54][55][56][57].…”

Dynamic depth-dependent osmotic swelling and solute diffusion in articular cartilage monitored using real-time ultrasound

“…These investigations have included studies on the assessment of progressive changes in the AC with experimental osteoarthritis (Saied et al 1997), the monitoring of the ultrasound parameters of AC during enzyme digestion (Nieminen et al 2002) and the measurement 5 of the inhomogeneous mechanical properties of AC during compression (Zheng et al 2001(Zheng et al , 2003aFortin et al 2003) (Refer to Zheng et al (2003) for a full list of relevant references). Local strains of AC tissues under compression can be measured or imaged using ultrasound so as to characterize AC in a nondestructive way.…”