Delayed gadolinium‐enhanced MRI of cartilage (dGEMRIC) and T₂ characteristics of human knee articular cartilage: Topographical variation and relationships to mechanical properties

Abstract

The macromolecular structure and mechanical properties of articular cartilage are interrelated and known to vary topographically in the human knee joint. To investigate the potential of delayed gadolinium-enhanced MRI of cartilage (dGEMRIC), T 1 , and T 2 mapping to elucidate these differences, full-thickness cartilage disks were prepared from six anatomical locations in nonarthritic human knee joints (N ‫؍‬ 13). Young's modulus and the dynamic modulus at 1 Hz were determined with the use of unconfined compression tests, followed by quantitative MRI measurements at 9.4 Tesla. Mechanical tests revealed reproducible, statistically significant differences in moduli between the patella and the medial/ lateral femoral condyles. Typically, femoral cartilage showed higher Young's (>1.0 MPa) and dynamic (>8 MPa) moduli than tibial or patellar cartilage (Young's modulus <0.9 MPa, dynamic modulus <8 MPa). dGEMRIC moderately reproduced the topographical variation in moduli. Additionally, T 1 , T 2 , and dGEMRIC revealed topographical differences that were not registered me-

Does Intraarticular Inflammation Predict Biomechanical Cartilage Properties?

“…The aggregate modulus in our study was within the range previously reported for normal human lateral femoral condyles [4,22,50]. However, the calculated dynamic modulus was lower than described by Kurkijärvi et al [22].…”

“…However, the calculated dynamic modulus was lower than described by Kurkijärvi et al [22]. They reported on the dynamic modulus of 13 nonarthritic samples of the distal lateral femur with a mean dynamic modulus of 10.0 MPa and a SD of 3.7 MPa.…”

“…They reported on the dynamic modulus of 13 nonarthritic samples of the distal lateral femur with a mean dynamic modulus of 10.0 MPa and a SD of 3.7 MPa. Whether these higher values are caused by the small sample size (n = 13) in their study or because they present samples from nonarthritic knees remains unclear [22]. The MRI synovitis grades did not correlate with cartilage biomechanics.…”

Probing articular cartilage damage and disease by quantitative magnetic resonance imaging

“…Nonetheless, T 1,Gd has been correlated with proteoglycan content [27,79,99]. T 1,Gd also varies depending on the region of cartilage [31,49] and is higher in load-bearing cartilage compared with non-contact regions [100]. Some studies have used dGEMRIC to compute GAG content in healthy cartilage [31] and cartilage with preradiographic damage [49].…”

“…T 1,Gd also varies depending on the region of cartilage [31,49] and is higher in load-bearing cartilage compared with non-contact regions [100]. Some studies have used dGEMRIC to compute GAG content in healthy cartilage [31] and cartilage with preradiographic damage [49]. Overall, T 1,Gd is lower with preradiographic damage [47] and with radiographic cartilage damage and OA [43,46,48] when compared with healthy joints.…”