Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada.
International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, Canada.
J Neuroimaging. 2020 Jan;30(1):50-57. doi: 10.1111/jon.12659. Epub 2019 Aug 13.
Acquiring and interpreting quantitative myelin-specific MRI data at an individual level is challenging because of technical difficulties and natural myelin variation in the population. To overcome these challenges, we used multiecho T myelin water imaging (MWI) to create T metric healthy population atlases that depict the mean and variation of myelin water fraction (MWF), and intra- and extracellular water mobility as described by geometric mean T (IEGMT ).
Cervical cord MWI was performed at 3T on 20 healthy individuals (10M/10F, mean age: 36 years) and 3 relapsing remitting multiple sclerosis (RRMS) participants (1M/2F, age: 39/42/37 years). Anatomical data were collected for the purpose of image segmentation and registration. Atlases were created by coregistering and averaging T metrics from all controls. Voxel-wise z-score maps from 3 RRMS participants were produced to demonstrate the preliminary utility of the MWF and IEGMT atlases.
The average MWF atlas provides a representation of myelin in the spinal cord consistent with well-known spinal cord anatomical characteristics. The IEGMT atlas also depicted structural variations in the spinal cord. Z-score analysis illustrated distinct abnormalities in MWF and IEGMT in the 3 RRMS cases.
Our findings highlight the potential for using a quantitative T relaxation metric atlas to visualize and detect pathology in spinal cord. Our MWF and IEGMT atlases (URL: https://sourceforge.net/projects/mwi-spinal-cord-atlases/) can serve as normative references in the cervical spinal cord for other studies.
由于技术难度和人群中天然髓鞘的变化，在个体水平上获取和解释定量的髓鞘特异性 MRI 数据具有挑战性。为了克服这些挑战，我们使用多回波 T 髓鞘水成像（MWI）创建 T 度量健康人群图谱，描述髓鞘水分数（MWF）的平均值和变化，以及由几何平均 T（IEGMT）描述的细胞内和细胞外水流动性。
在 3T 上对 20 名健康个体（10M/10F，平均年龄：36 岁）和 3 名复发缓解型多发性硬化症（RRMS）参与者（1M/2F，年龄：39/42/37 岁）进行颈髓 MWI。收集解剖数据用于图像分割和配准。通过对所有对照者的 T 度量进行配准和平均，创建图谱。对 3 名 RRMS 参与者的体素级 z 分数图进行制作，以展示 MWF 和 IEGMT 图谱的初步效用。
平均 MWF 图谱提供了与已知的脊髓解剖学特征一致的脊髓髓鞘的表示。IEGMT 图谱还描绘了脊髓的结构变化。z 分数分析表明，3 例 RRMS 病例的 MWF 和 IEGMT 存在明显异常。
我们的研究结果突出了使用定量 T 弛豫度量图谱可视化和检测脊髓病变的潜力。我们的 MWF 和 IEGMT 图谱（网址：https://sourceforge.net/projects/mwi-spinal-cord-atlases/）可作为其他研究中颈髓的正常参考。
