title: In vitro determination of biomechanical properties of human articular cartilage in osteoarthritis using multi-parametric MRI.
abstract: The objective of this study was to evaluate the correlations between MR parameters and the biomechanical properties of naturally degenerated human articular cartilage. Human cartilage explants from the femoral condyles of patients who underwent total knee replacement were evaluated on a micro-imaging system at 3T. To quantify glycosaminoglycan (GAG) content, delayed gadolinium-enhanced MRI of the cartilage (dGEMRIC) was used. T(2) maps were created by using multi-echo, multi-slice spin echo sequences with six echoes: 15, 30, 45, 60, 75, and 90 ms. Data for apparent diffusion constant (ADC) maps were obtained from pulsed gradient spin echo (PGSE) sequences with five b-values: 10.472, 220.0, 627.0, 452.8, 724.5, and 957.7. MR parameters were correlated with mechanical parameters (instantaneous (I) and equilibrium (Eq) modulus and relaxation time (tau)), and the OA stage of each cartilage specimen was determined by histological evaluation of hematoxylin-eosin stained slices. For some parameters, a high correlation was found: the correlation of T(1Gd) vs Eq (r=0.8095), T(1Gd) vs I/Eq (r=-0.8441) and T(1Gd) vs tau (r=0.8469). The correlation of T(2) and ADC with selected biomechanical parameters was not statistically significant. In conclusion, GAG content measured by dGEMRIC is highly related to the selected biomechanical properties of naturally degenerated articular cartilage. In contrast, T(2) and ADC were unable to estimate these properties. The results of the study imply that some MR parameters can non-invasively predict the biomechanical properties of degenerated articular cartilage.
authors.affiliation: MR Center, Highfield MR, Department of Radiology, Medical University of Vienna, Lazarettgasse 14, 1090 Vienna, Austria. vladimir.juras@meduniwien.ac.at
authors.forename: Vladimir
authors.initials: V
authors.lastname: Juras
authors.forename: Michal
authors.initials: M
authors.lastname: Bittsansky
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Majdisova
authors.forename: Pavol
authors.initials: P
authors.lastname: Szomolanyi
authors.forename: Irene
authors.initials: I
authors.lastname: Sulzbacher
authors.forename: Stefan
authors.initials: S
authors.lastname: Gäbler
authors.forename: Jürgen
authors.initials: J
authors.lastname: Stampfl
authors.forename: Georg
authors.initials: G
authors.lastname: Schüller
authors.forename: Siegfried
authors.initials: S
authors.lastname: Trattnig
mesh_terms: D001696:Biomechanical Phenomena; D002358:Cartilage, Articular / Q000473:pathology* / Q000503:physiopathology*; D003198:Computer Simulation; D055119:Elastic Modulus; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D066298:In Vitro Techniques; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008954:Models, Biological; D020370:Osteoarthritis, Knee / Q000473:pathology* / Q000503:physiopathology*; D013314:Stress, Mechanical
chemical_list: D006025:Glycosaminoglycans