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Open Access Research article

Ultrasonic reflection coefficient and surface roughness index of OA articular cartilage: relation to pathological assessment

Hai-jun Niu1*, Qing Wang2*, Yue-xiang Wang3, De-yu Li1, Yu-bo Fan1 and Wu-fan Chen2

Author Affiliations

1 Key Laboratory of the Ministry of Education for Biomechanics and Mechanobiology, School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China

2 School of Biomedical Engineering, Southern Medical University, Guangzhou 510515, China

3 Department of Ultrasound, People Liberation Army General Hospital, Beijing 100853, China

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BMC Musculoskeletal Disorders 2012, 13:34  doi:10.1186/1471-2474-13-34

Published: 10 March 2012

Abstract

Background

Early diagnosis of Osteoarthritis (OA) is essential for preventing further cartilage destruction and decreasing severe complications. The aims of this study are to explore the relationship between OA pathological grades and quantitative acoustic parameters and to provide more objective criteria for ultrasonic microscopic evaluation of the OA cartilage.

Methods

Articular cartilage samples were prepared from rabbit knees and scanned using ultrasound biomicroscopy (UBM). Three quantitative parameters, including the roughness index of the cartilage surface (URI), the reflection coefficients from the cartilage surface (R) and from the cartilage-bone interface (Rbone) were extracted. The osteoarthritis grades of these cartilage samples were qualitatively assessed by histology according to the grading standards of International Osteoarthritis Institute (OARSI). The relationship between these quantitative parameters and the osteoarthritis grades was explored.

Results

The results showed that URI increased with the OA grade. URI of the normal cartilage samples was significantly lower than the one of the OA cartilage samples. There was no significant difference in URI between the grade 1 cartilage samples and the grade 2 cartilage samples. The reflection coefficient of the cartilage surface reduced significantly with the development of OA (p < 0.05), while the reflection coefficient of the cartilage-bone interface increased with the increase of grade.

Conclusion

High frequency ultrasound measurements can reflect the changes in the surface roughness index and the ultrasound reflection coefficients of the cartilage samples with different OA grades. This study may provide useful information for the quantitative ultrasonic diagnosis of early OA.

Keywords:
Osteoarthritis; High-frequency ultrasound; Ultrasound roughness index; Ultrasound reflection coefficient