Comparison of ultrasound and optical coherence tomography techniques for evaluation of integrity of spontaneously repaired horse cartilage

Abstract

The aim of this study was to compare sensitivity of ultrasound and optical coherence tomography (OCT) techniques for the evaluation of the integrity of spontaneously repaired horse cartilage. Articular surfaces of horse intercarpal joints, featuring both intact tissue and spontaneously healed chondral or osteochondral defects, were imaged ex vivo with arthroscopic ultrasound and laboratory OCT devices. Quantitative ultrasound (integrated reflection coefficient (IRC), apparent integrated backscattering coefficient (AIB) and ultrasound roughness index (URI)) and optical parameters (optical reflection coefficient (ORC), optical roughness index (ORI) and optical backscattering (OBS)) were determined and compared with histological integrity and mechanical properties of the tissue. Spontaneously healed tissue could be quantitatively discerned from the intact tissue with ultrasound and OCT techniques. Furthermore, several significant correlations (p < 0.05) were detected between ultrasound and OCT parameters. Superior resolution of OCT provided a more accurate measurement of cartilage surface roughness, while the ultrasound backscattering from the inner structures of the cartilage matched better with the histological findings. Since the techniques were found to be complementary to each other, dual modality imaging techniques could provide a useful tool for the arthroscopic evaluation of the integrity of articular cartilage.

Keywords::

• Articular cartilage
• Cartilage repair
• High-frequency ultrasound
• Optical coherence tomography
• Quantitative characterization

Acknowledgements

We thank Mr Wang for his technical support with the OCT measurements of cartilage.

Declaration of interest: The authors have no conflicts of interest. Financial support from Kuopion University Hospital (EVO grant 5227), Strategic funding of the University of Eastern Finland, Päivikki and Sakkari Sohlberg Foundation, Academy of Finland (projects 127198, 132367 and 128117), Sigrid Juselius Foundation, Jenny and Antti Wihuri Foundation, TBDB graduate school, Instrumentarium foundation, Finnish Funding Agency for Technology and Innovation (TEKES grant 262/04) and from Jyväskylä Central Hospital (grant B0206) is acknowledged.