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Development of a rapid knee cartilage damage quantification method using magnetic resonance images.

Zhang M, Driban JB, Price LL, Harper D, Lo GH, Miller E, Ward RJ, McAlindon TE - BMC Musculoskelet Disord (2014)

Bottom Line: We tested the intra- and inter-tester reliability of the CDI and compared the CDI scores against different measures of severity (radiographic joint space narrowing [JSN] grade, KL score, joint space width [JSW]) and static knee alignment, both cross-sectionally and longitudinally.Baseline JSN grade and knee alignment also predicted subsequent 24-month longitudinal change in the CDI (p trends <0.05).During 24 months, knees with worsening in JSN or KL grade (i.e. progressors) had greater change in CDI score.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Rheumatology, Tufts Medical Center, 800 Washington Street, Box #406, Boston, MA 02111, USA. tmcalindon@tuftsmedicalcenter.org.

ABSTRACT

Background: Cartilage morphometry based on magnetic resonance images (MRIs) is an emerging outcome measure for clinical trials among patients with knee osteoarthritis (KOA). However, current methods for cartilage morphometry take many hours per knee and require extensive training on the use of the associated software. In this study we tested the feasibility, reliability, and construct validity of a novel osteoarthritis cartilage damage quantification method (Cartilage Damage Index [CDI]) that utilizes informative locations on knee MRIs.

Methods: We selected 102 knee MRIs from the Osteoarthritis Initiative that represented a range of KOA structural severity (Kellgren Lawrence [KL] Grade 0 - 4). We tested the intra- and inter-tester reliability of the CDI and compared the CDI scores against different measures of severity (radiographic joint space narrowing [JSN] grade, KL score, joint space width [JSW]) and static knee alignment, both cross-sectionally and longitudinally.

Results: Determination of the CDI took on average14.4 minutes (s.d. 2.1) per knee pair (baseline and follow-up of one knee). Repeatability was good (intra- and inter-tester reliability: intraclass correlation coefficient >0.86). The mean CDI scores related to all four measures of osteoarthritis severity (JSN grade, KL score, JSW, and knee alignment; all p values < 0.05). Baseline JSN grade and knee alignment also predicted subsequent 24-month longitudinal change in the CDI (p trends <0.05). During 24 months, knees with worsening in JSN or KL grade (i.e. progressors) had greater change in CDI score.

Conclusions: The CDI is a novel knee cartilage quantification method that is rapid, reliable, and has construct validity for assessment of medial tibiofemoral osteoarthritis structural severity and its progression. It has the potential to addresses the barriers inherent to studies requiring assessment of cartilage damage on large numbers of knees, and as a biomarker for knee osteoarthritis progression.

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CDI measurement of the medial tibiofemoral compartment.
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Figure 2: CDI measurement of the medial tibiofemoral compartment.

Mentions: One investigator (MZ), who was blinded to the outcome measures, performed the CDI measurement on paired baseline and 24-month follow-up MR images. The investigator was not blinded to the order of images (baseline or follow-up). The investigator used customized software to (1) translate an articular surface into a 2-dimensional coordinate matrix, (2) localize 9 pre-defined informative locations (characterized by a greater propensity to exhibit cartilage loss), and (3) measure cartilage thickness at those locations (Figure 1). To co-locate the corresponding informative locations on baseline and follow-up images, we used dual screens to permit simultaneous visual comparison of the MR image sets.In the first step the reader indicated the most medial and lateral MR image slices within the knee. These images designated the minimum and maximum values of the medial-to-lateral axis on the 2-dimensional coordinate system. Next, the software automatically determined the MR image slices that contained the informative locations. On each of these slices the investigator manually traced the bone-cartilage boundary using predefined segmentation rules. The software then translated the length of the bone-cartilage boundary to a standardized anterior-to-posterior axis and indicated the predefined informative locations so that the investigator could measure the cartilage thickness at those points (Figure 2). The software then computed the cartilage damage index (CDI) by summing the products of cartilage thickness, cartilage length (anterior-posterior), and voxel size from each informative location.


Development of a rapid knee cartilage damage quantification method using magnetic resonance images.

Zhang M, Driban JB, Price LL, Harper D, Lo GH, Miller E, Ward RJ, McAlindon TE - BMC Musculoskelet Disord (2014)

CDI measurement of the medial tibiofemoral compartment.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4126278&req=5

Figure 2: CDI measurement of the medial tibiofemoral compartment.
Mentions: One investigator (MZ), who was blinded to the outcome measures, performed the CDI measurement on paired baseline and 24-month follow-up MR images. The investigator was not blinded to the order of images (baseline or follow-up). The investigator used customized software to (1) translate an articular surface into a 2-dimensional coordinate matrix, (2) localize 9 pre-defined informative locations (characterized by a greater propensity to exhibit cartilage loss), and (3) measure cartilage thickness at those locations (Figure 1). To co-locate the corresponding informative locations on baseline and follow-up images, we used dual screens to permit simultaneous visual comparison of the MR image sets.In the first step the reader indicated the most medial and lateral MR image slices within the knee. These images designated the minimum and maximum values of the medial-to-lateral axis on the 2-dimensional coordinate system. Next, the software automatically determined the MR image slices that contained the informative locations. On each of these slices the investigator manually traced the bone-cartilage boundary using predefined segmentation rules. The software then translated the length of the bone-cartilage boundary to a standardized anterior-to-posterior axis and indicated the predefined informative locations so that the investigator could measure the cartilage thickness at those points (Figure 2). The software then computed the cartilage damage index (CDI) by summing the products of cartilage thickness, cartilage length (anterior-posterior), and voxel size from each informative location.

Bottom Line: We tested the intra- and inter-tester reliability of the CDI and compared the CDI scores against different measures of severity (radiographic joint space narrowing [JSN] grade, KL score, joint space width [JSW]) and static knee alignment, both cross-sectionally and longitudinally.Baseline JSN grade and knee alignment also predicted subsequent 24-month longitudinal change in the CDI (p trends <0.05).During 24 months, knees with worsening in JSN or KL grade (i.e. progressors) had greater change in CDI score.

View Article: PubMed Central - HTML - PubMed

Affiliation: Division of Rheumatology, Tufts Medical Center, 800 Washington Street, Box #406, Boston, MA 02111, USA. tmcalindon@tuftsmedicalcenter.org.

ABSTRACT

Background: Cartilage morphometry based on magnetic resonance images (MRIs) is an emerging outcome measure for clinical trials among patients with knee osteoarthritis (KOA). However, current methods for cartilage morphometry take many hours per knee and require extensive training on the use of the associated software. In this study we tested the feasibility, reliability, and construct validity of a novel osteoarthritis cartilage damage quantification method (Cartilage Damage Index [CDI]) that utilizes informative locations on knee MRIs.

Methods: We selected 102 knee MRIs from the Osteoarthritis Initiative that represented a range of KOA structural severity (Kellgren Lawrence [KL] Grade 0 - 4). We tested the intra- and inter-tester reliability of the CDI and compared the CDI scores against different measures of severity (radiographic joint space narrowing [JSN] grade, KL score, joint space width [JSW]) and static knee alignment, both cross-sectionally and longitudinally.

Results: Determination of the CDI took on average14.4 minutes (s.d. 2.1) per knee pair (baseline and follow-up of one knee). Repeatability was good (intra- and inter-tester reliability: intraclass correlation coefficient >0.86). The mean CDI scores related to all four measures of osteoarthritis severity (JSN grade, KL score, JSW, and knee alignment; all p values < 0.05). Baseline JSN grade and knee alignment also predicted subsequent 24-month longitudinal change in the CDI (p trends <0.05). During 24 months, knees with worsening in JSN or KL grade (i.e. progressors) had greater change in CDI score.

Conclusions: The CDI is a novel knee cartilage quantification method that is rapid, reliable, and has construct validity for assessment of medial tibiofemoral osteoarthritis structural severity and its progression. It has the potential to addresses the barriers inherent to studies requiring assessment of cartilage damage on large numbers of knees, and as a biomarker for knee osteoarthritis progression.

Show MeSH
Related in: MedlinePlus