Sabine Weckbach MD, Presenter: Nothing to Disclose

Annie Horng MD, Abstract Co-Author: Nothing to Disclose

Gudrun Pforte, Abstract Co-Author: Nothing to Disclose

Maximilian F. Reiser MD, Abstract Co-Author: Nothing to Disclose

Christian Glaser MD, Abstract Co-Author: Nothing to Disclose

In the diagnostic process of osteoarthrosis (OA) there is no tool for quantitative grading of disease as there is, for example, in osteoporosis. However, especially considering therapeutic decision making a tool with cut off-values for the diagnosis of OA and its different stages of severity would be of high interest especially with respect to a simple pratical day-to-day approach. Therefore the purpose of this study was to evaluate T-scores based on quantitative cartilage volumetric parameters for the diagnosis of patellofemoral osteoarthritis.

69 patients (39 female) with clinically proven patellofemoral OA classified according to the Kellgren-Lawrence-Score were compared to 185 healthy subjects (76 female, all < 35years). A sagittal 3D FLASH WE sequence (0.32 x 2 mm3) was acquired at 1.5 T. After semiautomatic segmentation, volume, mean thickness and volume normalized to cartilage bone interface (vol/CBI) were calculated. T-Scores, ROC-curves, AUC and sensitivity /specificity for selected cutoff values were calculated.   

Using vol/CBI the highest sensitivity (1.000) and specificity (0.978) for the diagnosis “OA” was reached at a T-value of -1.935. Using a T-value of -2.4862 (comparable to -2.5 for osteoporosis), sensitivity was 0.942 and specificity 0.995. Using the lowest observed T-value of -2.987, sensitivity is 0.884 and specificity 1.000. The AUC from vol/CBI is 0.999, from volume and mean thickness 0.980 and 0.891 with p < 0.001. An AUC value of 1.000 is reached for the female subgroup for vol/CBI.

In this study a cutoff T-value of -1.9 yields highest sensitivity whereas a T-value of -2.5 would moderately increase specificity at the cost of some sensitivity. AUC values indicate that vol/CBI has the best discriminatory power for patellofemoral OA among the available parameters. Sensitivities and specificities obtained for selected cutoff values suggest that T-scores based on quantitative cartilage volumetric parameters may be a suitable adjunct for the diagnostic workup of OA in population based approaches.

T-scores based on quantitative cartilage volumetric parameters may be a suitable adjunct for the diagnostic workup of OA in population based approaches.

Weckbach, S, Horng, A, Pforte, G, Reiser, M, Glaser, C, T-Scores for Osteoarthrosis of the Patellofemoral Joint Using Quantitative MR Volumetry of Cartilage  .  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8006072.html