title: Sensitivity and specificity of univariate MRI analysis of experimentally degraded cartilage.
abstract: MRI is increasingly used to evaluate cartilage in tissue constructs, explants, and animal and patient studies. However, while mean values of MR parameters, including T(1), T(2), magnetization transfer rate k(m), apparent diffusion coefficient (ADC), and the dGEMRIC-derived fixed charge density, correlate with tissue status, the ability to classify tissue according to these parameters has not been explored. Therefore, the sensitivity and specificity with which each of these parameters was able to distinguish between normal and trypsin-degraded, and between normal and collagenase-degraded, cartilage explants were determined. Initial analysis was performed using a training set to determine simple group means to which parameters obtained from a validation set were compared. T(1) and apparent diffusion coefficient showed the greatest ability to discriminate between normal and degraded cartilage. Further analysis with k-means clustering, which eliminates the need for a priori identification of sample status, generally performed comparably. Use of fuzzy c-means (FCM) clustering to define centroids likewise did not result in improvement in discrimination. Finally, an FCM clustering approach in which validation samples were assigned in a probabilistic fashion to control and degraded groups was implemented, reflecting the range of tissue characteristics seen with cartilage degradation.
authors.affiliation: Magnetic Resonance Imaging and Spectroscopy Section, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA.
authors.forename: Ping-Chang
authors.initials: PC
authors.lastname: Lin
authors.forename: David A
authors.initials: DA
authors.lastname: Reiter
authors.forename: Richard G
authors.initials: RG
authors.lastname: Spencer
mesh_terms: D000465:Algorithms; D000818:Animals; D002356:Cartilage / Q000473:pathology*; D002357:Cartilage Diseases / Q000473:pathology*; D002417:Cattle; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
references.citation: Magn Reson Med. 2006 Aug;56(2):386-94
references.pmid: 16767752
references.citation: Invest Radiol. 2000 Oct;35(10):622-38
references.pmid: 11041156
references.citation: J Magn Reson Imaging. 2003 Apr;17(4):440-4
references.pmid: 12655583
references.citation: J Orthop Res. 2004 May;22(3):557-64
references.pmid: 15099635
references.citation: Magn Reson Med. 2007 Jun;57(6):1000-11
references.pmid: 17534923
references.citation: Eur Cell Mater. 2007 Apr 03;13:46-55; discussion 55
references.pmid: 17407053
references.citation: Arthritis Rheum. 2001 Apr;44(4):846-55
references.pmid: 11315924
references.citation: Front Biosci. 1999 Oct 15;4:D662-70
references.pmid: 10525481
references.citation: Magn Reson Med. 1996 Nov;36(5):665-73
references.pmid: 8916016
references.citation: Magn Reson Med. 2000 May;43(5):676-81
references.pmid: 10800032
references.citation: Magn Reson Med. 2004 Mar;51(3):503-9
references.pmid: 15004791
references.citation: J Anat. 2006 Aug;209(2):259-67
references.pmid: 16879604
references.citation: J Comput Assist Tomogr. 1992 Jan-Feb;16(1):7-18
references.pmid: 1729310
references.citation: Magn Reson Imaging. 2001 Dec;19(10):1279-86
references.pmid: 11804755
references.citation: Magn Reson Imaging. 1999 Sep;17(7):1065-76
references.pmid: 10463658