title: Ultrasound arthroscopy of human knee cartilage and subchondral bone in vivo.
abstract: Arthroscopic ultrasound imaging enables quantitative evaluation of articular cartilage. However, the potential of this technique for evaluation of subchondral bone has not been investigated in vivo. In this study, we address this issue in clinical arthroscopy of the human knee (n = 11) by determining quantitative ultrasound (9 MHz) reflection and backscattering parameters for cartilage and subchondral bone. Furthermore, in each knee, seven anatomical sites were graded using the International Cartilage Repair Society (ICRS) system based on (i) conventional arthroscopy and (ii) ultrasound images acquired in arthroscopy with a miniature transducer. Ultrasound enabled visualization of articular cartilage and subchondral bone. ICRS grades based on ultrasound images were higher (p < 0.05) than those based on conventional arthroscopy. The higher ultrasound-based ICRS grades were expected as ultrasound reveals additional information on, for example, the relative depth of the lesion. In line with previous literature, ultrasound reflection and scattering in cartilage varied significantly (p < 0.05) along the ICRS scale. However, no significant correlation between ultrasound parameters and structure or density of subchondral bone could be demonstrated. To conclude, arthroscopic ultrasound imaging had a significant effect on clinical grading of cartilage, and it was found to provide quantitative information on cartilage. The lack of correlation between the ultrasound parameters and bone properties may be related to lesser bone change or excessive attenuation in overlying cartilage and insufficient power of the applied miniature transducer.
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland. Electronic address: jukka.liukkonen@uef.fi.
authors.forename: Jukka
authors.initials: J
authors.lastname: Liukkonen
authors.affiliation: Department of Anatomy and Cell Biology, Institute of Biomedicine, University of Oulu, Oulu, Finland; Department of Surgery, Medical Research Center, Oulu University Hospital, Oulu, Finland; Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland.
authors.forename: Petri
authors.initials: P
authors.lastname: Lehenkari
authors.affiliation: Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland; Department of Medical Technology, University of Oulu, Oulu, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Hirvasniemi
authors.affiliation: Department of Orthopaedics, Traumatology and Hand Surgery, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Joukainen
authors.affiliation: Cancer Center, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Tuomas
authors.initials: T
authors.lastname: Virén
authors.affiliation: Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland; Department of Medical Technology, University of Oulu, Oulu, Finland; Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland.
authors.forename: Simo
authors.initials: S
authors.lastname: Saarakkala
authors.affiliation: Medical Research Center Oulu, Oulu University Hospital and University of Oulu, Oulu, Finland; Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; Department of Radiology, University of Oulu, Oulu, Finland.
authors.forename: Miika T
authors.initials: MT
authors.lastname: Nieminen
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland.
authors.forename: Jukka S
authors.initials: JS
authors.lastname: Jurvelin
authors.affiliation: Department of Applied Physics, University of Eastern Finland, Kuopio, Finland; Department of Clinical Neurophysiology, Kuopio University Hospital, Kuopio, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Töyräs
mesh_terms: D000328:Adult; D000368:Aged; D001182:Arthroscopy / Q000379:methods*; D002358:Cartilage, Articular / Q000000981:diagnostic imaging* / Q000601:surgery; D003287:Contrast Media; D005240:Feasibility Studies; D019786:Gadolinium DTPA; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D007485:Ioxaglic Acid; D007717:Knee / Q000000981:diagnostic imaging* / Q000601:surgery; D007719:Knee Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D008875:Middle Aged; D011300:Preoperative Care / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA; D007485:Ioxaglic Acid
keywords: Arthroscopy; Articular cartilage; High frequency; Imaging; International Cartilage Repair Society score; Knee; Osteoarthritis; Subchondral bone; Ultrasound