Cartilage Restoration Laboratory, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA 15213, United States.
Osteoarthritis Cartilage. 2010 Apr;18(4):539-46. doi: 10.1016/j.joca.2010.02.001. Epub 2010 Feb 6.
To examine the sensitivity of ultra-short echo time (UTE) T(2)* mapping to collagen matrix degeneration in human articular cartilage.
Magnetic resonance imaging (MRI) UTE-T(2)* maps and standard T(2) maps were acquired on four human tibial plateau explants. Thirty-three osteochondral cores were harvested for polarized light microscopy (PLM), and composition analyses. Collagen matrix integrity was evaluated from PLM and histological images. Matrix integrity and composition was compared to standard T(2) values and UTE-T(2)* values on a spatially registered basis.
UTE-T(2)* values varied with matrix degeneration (P=0.008) and were lower in severely degraded cartilage compared to healthy tissue (P=0.012). A trend for higher UTE-T(2)* values in healthy tissue compared to mildly degenerate tissue (P=0.051) was detected. Standard T(2) values were not found to vary with matrix degeneration (P=0.13) but tended to be higher in severely degraded cartilage compared to healthy tissue. UTE-T(2)* value variations were independent of type-II collagen and glycosaminoglycan contents. UTE-T(2)* mapping of deep cartilage, adjacent to subchondral bone, was more robust than standard T(2) mapping in this zone.
UTE-T(2)* mapping of articular cartilage is sensitive to matrix degeneration and detects short-T(2) signal, particularly in deep tissue, that is not well captured by standard T(2) mapping. Correlation of UTE-T(2)* values and PLM indices supports the hypothesis that both may be sensitive to collagen microstructure. Further exploration of UTE-T(2)* mapping as a non-invasive tool to detect early articular cartilage degeneration is warranted.
探讨超短回波时间（UTE）T*（2）映射在人类关节软骨胶原基质退变中的敏感性。
对 4 个人胫骨平台标本进行磁共振成像（MRI）UTE-T*（2）映射和标准 T*（2）映射。采集 33 个骨软骨核用于偏光显微镜（PLM）和成分分析。从 PLM 和组织学图像评估胶原基质完整性。在空间配准的基础上，将基质完整性和组成与标准 T*（2）值和 UTE-T*（2）值进行比较。
UTE-T*（2）值随基质退变而变化（P=0.008），与健康组织相比，严重退变软骨的 UTE-T*（2）值较低（P=0.012）。检测到健康组织的 UTE-T*（2）值比轻度退变组织高（P=0.051）的趋势。未发现标准 T*（2）值随基质退变而变化（P=0.13），但与健康组织相比，严重退变软骨的标准 T*（2）值较高。UTE-T*（2）值的变化与 II 型胶原和糖胺聚糖含量无关。与标准 T*（2）映射相比，软骨深层（毗邻软骨下骨）的 UTE-T*（2）映射在该区域更为稳健。
关节软骨的 UTE-T*（2）映射对基质退变敏感，并检测到标准 T*（2）映射无法很好捕捉的短 T*（2）信号，特别是在深层组织中。UTE-T*（2）值与 PLM 指数的相关性支持这样一种假设，即两者都可能对胶原微观结构敏感。进一步探索 UTE-T*（2）映射作为一种非侵入性工具来检测早期关节软骨退变是有必要的。
