Alkalay Ron, David Hackney
Center for Advanced Orthopaedic Studies, Department of Orthopedics, Beth Israel Deaconess Medical Center and Harvard medical School, Boston, MA, United States.
Department of Radiology, Beth Israel Deaconess Medical Center and Harvard medical School, Boston, MA, United States of America.
Clin Biomech (Bristol). 2019 Jan;61:38-45. doi: 10.1016/j.clinbiomech.2018.06.007. Epub 2018 Jun 18.
Understanding the association between MR parameters and age related deterioration in human intervertebral disks forms an important step in the development of clinical diagnostic protocols for disk disease.
Ten unfixed thoracic and lumbar cadaver disk joints, age 37-81 years were imaged at 9.4 T using T2 relaxation (CPMG) and ADC (DWI spin echo) MR protocols. For each MR parameter, spatial maps were computed from the axial images, with the AF and NP segmented based on the T2 maps. Linear regression tested for the correlation between mean and variance (COV) of T2 and ADC with age in the disk, nucleus and annulus, and the effect of thoracic vs. lumbar spine on these correlations.
In the disk, age negatively correlated with mean ADC (P < 0.001) and positively with COV of ADC (P < 0.001) and T2 (P < 0.05). Age was negatively correlated with mean T2 (P < 0.01), mean ADC (P < 0.001) and positively with COV of ADC (P < 0.001) and T2 (P < 0.05) in the NP and positively correlated with mean T2 (P < 0.05), COV of ADC (P < 0.01) and T2 (P < 0.05) and negatively with mean ADC (P < 0.05) in the AF. Compared to thoracic disks, lumbar disks showed higher mean ADC (P < 0.05), lower mean T2 (P < 0.001) and higher COV of ADC (P < 0.01) and T2 (P < 0.05).
Compared to T2, MR diffusion was a more sensitive measure of age mediated changes in disk tissues. Strong differences in the association of MR parameters with age between the lumbar and thoracic suggest that mechanical environment effects tissue specific MR parameters' association with age.
了解磁共振成像（MR）参数与人类椎间盘年龄相关退变之间的关联是制定椎间盘疾病临床诊断方案的重要一步。
对10个未固定的胸腰椎尸体椎间盘关节（年龄37 - 81岁）在9.4T磁场下采用T2弛豫（CPMG）和表观扩散系数（ADC，扩散加权成像自旋回波）MR协议进行成像。对于每个MR参数，从轴向图像计算空间图，并根据T2图对纤维环（AF）和髓核（NP）进行分割。采用线性回归分析椎间盘、髓核和纤维环中T2和ADC的均值及变异系数（COV）与年龄之间的相关性，以及胸段与腰段脊柱对这些相关性的影响。
在椎间盘内，年龄与平均ADC呈负相关（P < 0.001），与ADC的COV呈正相关（P < 0.001），与T2呈正相关（P < 0.05）。在髓核中，年龄与平均T2呈负相关（P < 0.01）、与平均ADC呈负相关（P < 0.001），与ADC的COV呈正相关（P < 0.001），与T2呈正相关（P < 0.05）；在纤维环中，年龄与平均T2呈正相关（P < 0.05）、与ADC的COV呈正相关（P < 0.01），与T2呈正相关（P < 0.05），与平均ADC呈负相关（P < 0.05）。与胸段椎间盘相比，腰段椎间盘的平均ADC更高（P < 0.05），平均T2更低（P < 0.001），ADC的COV更高（P < 0.01），T2的COV更高（P < 0.05）。
与T2相比，MR扩散是椎间盘组织中年龄介导变化更敏感的指标。腰段和胸段之间MR参数与年龄的关联存在显著差异，提示力学环境影响组织特异性MR参数与年龄的关联。
