Ultrasound elastomicroscopy for articular cartilage: From static to transient and id to 2d

Yongping Zheng, S. L. Bridal, J. Shi, A. Saied, M. H. Lu, B. Jaffre, A. F.T. Mak, P. Laugier, L. Qin

Research output: Journal article publicationConference articleAcademic researchpeer-review

2 Citations (Scopus)

Abstract

Articular cartilage (AC) is a biological weight-bearing tissue covering the ends of articulating bones within synovial joints. Its function very much depends on the unique multi-layered structure and the depth-dependent material properties, which have not been well investigated nondestructively. In this study, transient depth-dependent material properties of bovine patella cartilage were measured using ultrasound elastomicroscopy methods. A 50 MHz focused ultrasound transducer was used to collect A-mode ultrasound echoes from the articular cartilage during the compression and subsequent force-relaxation. The transient displacements of the cartilage tissues at different depths were calculated from the ultrasound echoes using a cross-correlation technique. It was observed that the strains in the superficial zone were much larger than those in the middle and deep zones as the equilibrium state was approached. The tissues inside the AC layer continued to move during the force-relaxation phase after the compression was completed. This process has been predicted by a biphasic theory. In this study, it has been verified experimentally. It was also observed that the tissue deformations at different depths of AC were much more evenly distributed before force-relaxation. AC specimens were also investigated using a 2D ultrasound elastomicroscopy system that included a 3D translating system for moving the ultrasound transducer over the specimens. B-mode RF ultrasound signals were collected from the specimens under different loading levels applied with a specially designed compressor. Preliminary results demonstrated that the scanning was repeatable with high correlation of radio frequency signals obtained from the same site during different scans when compression level was unchanged (R2> 0.97). Strains of the AC specimens were mapped using data collected with this ultrasound elastomicroscope. This system can also be potentially used for the assessment of other biological tissues, bioengineered tissues or biomaterials with fine structures.
Original languageEnglish
Pages (from-to)398-410
Number of pages13
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume5035
DOIs
Publication statusPublished - 12 Sep 2003
EventMedical Imaging 2003: Ultrasonic Imaging and Signal Processing - San Diego, CA, United States
Duration: 18 Feb 200320 Feb 2003

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering

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