title: 3-D high-frequency ultrasound backscatter analysis of human articular cartilage.
abstract: High-frequency ultrasound is a promising method for non-invasive characterization of cartilage degeneration. Surface reflection and integrated spectral parameters are often used. In the work described here, human cartilage samples with varying degrees of degeneration were measured using a 40-MHz transducer. Backscatter signals originating from the superficial and transitional zones of cartilage were analyzed using amplitude, spectral and envelope statistical parameters and related to degenerative changes of the matrix given by the Mankin score. The results indicate an increased sensitivity of spectral slope and envelope statistical parameters to early matrix degeneration compared with conventional amplitude parameters. Furthermore, moderate correlations of chondrocyte number with backscatter amplitude and envelope statistics were observed, suggesting that at high frequencies, cells are one important scattering source in cartilage. An application of spectral and envelope statistical parameters to intra-articular ultrasound arthroscopy is conceivable and could improve the diagnostic potential of these examinations. Future studies are necessary to clarify the contributions of chondrocytes, extracellular matrix and collagen content to ultrasound backscatter to further improve the diagnostic potential of ultrasound for cartilage assessment.
authors.affiliation: Julius Wolff Institute and Berlin-Brandenburg School for Regenerative Therapies, Charité-Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: Nils
authors.initials: N
authors.lastname: Männicke
authors.forename: Martin
authors.initials: M
authors.lastname: Schöne
authors.forename: Matthias
authors.initials: M
authors.lastname: Gottwald
authors.forename: Felix
authors.initials: F
authors.lastname: Göbel
authors.forename: Michael L
authors.initials: ML
authors.lastname: Oelze
authors.forename: Kay
authors.initials: K
authors.lastname: Raum
mesh_terms: D000465:Algorithms; D002357:Cartilage Diseases / Q000000981:diagnostic imaging*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014463:Ultrasonography / Q000379:methods*
keywords: Backscatter; Cartilage; Degeneration; Envelope statistics; High-frequency ultrasound; Osteoarthritis; Quantitative ultrasound; Spectral slope; Ultrasound bio-microscopy; Ultrasound spectroscopy