Author: Cheung, James
Title: Characterization of normal and degenerated articular cartilage using ultrasound biomicroscope in vitro
Degree: M.Sc.
Year: 2005
Subject: Hong Kong Polytechnic University -- Dissertations
Articular cartilage -- Wounds and injuries
Ultrasonic imaging
Ultrasonics in medicine
Department: Jockey Club Rehabilitation Engineering Centre
Pages: xi, 97 p. : ill. (some col.) ; 30 cm.
Language: English
Abstract: Articular cartilage (ArtC) is a biological weight-bearing tissue covering the ends of articulating bones within synovial joints. It is essential for joint lubrication and load transmission. The mechanical properties of the ArtC are different at locations and depths. Osteoarthritis (OA) is the most common joint disease. It affects the majority of adults over 65 years old. The early signs of OA include tissue softening and disruption of the ArtC surface, resulting in a change from a smooth appearance to a fibrillated appearance. To detect ArtC changes that occur in early OA has significant clinical values. Since the 90's, ultrasound biomicroscopes have been widely used for the morphological and biomechanical assessment of ArtC. The ArtC thickness measured by ultrasound and the acoustic parameters including integrated attenuation (IA) and backscattering (IBS) has been reported earlier to be sensitive to the ArtC degeneration. In this study, an ultrasound biomicroscope system was used to examine ArtC samples from various locations of bovine knee joints. 60 specimens were collected from patella, femur and tibia. These specimens were divided into two groups (A and B), which were treated using trypsin and collagenase respectively for simulating ArtC degeneration. The optimal time and concentration of enzyme for partially digesting different ArtC components were determined by a pilot study. All specimens were examined by the digital camera and ultrasound biomicroscope system before and after the treatment. These raw data were used to calculate various ultrasonic parameters using Matlab programs.
Results showed that the thickness of the specimens was overall significantly (p=0.01) change after collagenase treatment. Under saturation, the IBS obtained from femur, tibia, patella and all condyles data showed a significantly (p=0.029, p=0.038, p=0.027, p<0.001 with collagenase) changes. However, the slope of attenuation obtained from patella and overall condyles data also showed a significantly (p=0.01, p=0.008 with trypsin) changes. IA showed limited results. Under unsaturation, the centrioid frequency of the echo of ArtC surface from the femur condyle data showed significantly (p<0.001 with trypsin, p=0.021 with collagenase) changes. The tibia and overall condyle data showed significantly (p=0.012, p<0.001 with trypsin) change as well. The amplitude of the echo obtained from ArtC surface of the femur, tibia, patella and overall condyle data showed significantly (p<0.001, p=0.008, p<0.001, p<0.001 with trypsin; p=0.021, p=0.034, p<0.001, p<0.001 with collagenase) changes after treatment. The amplitude of the echo obtained from the ArtC/bone interface of the patella and overall condyle data showed significantly (p=0.003 p<0.001 with trypsin; p=0.004, p=0.003 with collagenase) changes. In conclusion, the digital camera was shown the ability to detect the change in specimen thickness induced by enzyme. The ultrasound biomicroscope was demonstrated the ability to detect the change in echo amplitude from both interfaces induced by different enzymes. The change in proteoglycan content was able to detect by the centroid frequency shift of the echo from ArtC surface. And, the change in collagen content was able to detect by IBS change. Since, lower proteoglycan content, increase in surface roughness and water content are observed in early OA development which may able to detect by the 40 MHz ultrasound biomicroscope used in this study.
Rights: All rights reserved
Access: restricted access

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