Minimally Invasive Ultrasound Method for Intra-Articular Diagnostics of Cartilage Degeneration

Virén, T.; Saarakkala, S.; Kaleva, E.; Nieminen, H.J.; Jurvelin, J.S.; Töyräs, J.

doi:10.1016/j.ultrasmedbio.2009.04.004

« Previous Next »Ultrasound in Medicine and Biology
Volume 35, Issue 9 , Pages 1546-1554, September 2009

Minimally Invasive Ultrasound Method for Intra-Articular Diagnostics of Cartilage Degeneration

T. Virén
- Department of Physics, University of Kuopio, Kuopio University Hospital, Kuopio, Finland
- Address correspondence to: Tuomas Virén, Department of Physics, University of Kuopio, POB 1627, FI-70211 Kuopio, Finland.
S. Saarakkala
- Department of Physics, University of Kuopio, Kuopio University Hospital, Kuopio, Finland
E. Kaleva
- Department of Physics, University of Kuopio, Kuopio University Hospital, Kuopio, Finland
H.J. Nieminen
- Department of Physics, University of Kuopio, Kuopio University Hospital, Kuopio, Finland
J.S. Jurvelin
- Department of Physics, University of Kuopio, Kuopio University Hospital, Kuopio, Finland
J. Töyräs
- Department of Physics, University of Kuopio, Kuopio University Hospital, Kuopio, Finland
- Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland

Received 6 October 2008; received in revised form 23 March 2009; accepted 8 April 2009. published online 29 June 2009.

Abstract

Quantitative ultrasound imaging (QUI) can be used to evaluate the integrity of articular cartilage and for diagnosing the early signs of osteoarthritis (OA). In this study, we applied a minimally invasive ultrasound imaging technique and investigated its ability to detect superficial degeneration of bovine knee articular cartilage. Intact (n=13), collagenase-digested (n=6) and mechanically degraded (n=7) osteochondral samples (dia.=25 mm) and custom-made phantoms with different degrees of surface roughness (n=8) were imaged using a high-frequency (40 MHz) QUI system. For each sample and phantom, the ultrasound reflection coefficient (R), integrated reflection coefficient (IRC) and ultrasound roughness index (URI) were determined. Furthermore, to evaluate the clinical applicability of intra-articular ultrasound (IAUS) in diagnostics, one intact bovine knee joint was investigated ex vivo using a simulated arthroscopic approach. Differences in the surface characteristics of the phantoms were detected by monitoring changes in the reflection and surface roughness parameters. Both mechanically- and enzymatically-induced degradation were sensitively diagnosed by decreased (p<0.05) reflection (R and IRC) at the cartilage surface. Furthermore, mechanical degradation was detected in the increased (p<0.05) surface roughness (URI). The intra-articular investigation of a bovine knee joint suggested that the IAUS technique may enable minimally invasive, straightforward diagnostics of the degenerative status of the articular surfaces. We conclude that quantitative IAUS imaging can be used for detecting collagen disruption and increased roughness of the articular surface. This quantitative in vivo ultrasound technique could have great clinical value in the diagnostics of joint diseases. (E-mail: tviren@hytti.uku.fi)