7T 下高分辨率人颈椎脊髓成像。
High-resolution human cervical spinal cord imaging at 7 T.
机构信息
Department of Radiology, New York University Langone Medical Center, New York, NY, USA.
出版信息
NMR Biomed. 2012 Jul;25(7):891-9. doi: 10.1002/nbm.1809. Epub 2011 Dec 20.
We present high-resolution anatomical imaging of the cervical spinal cord in healthy volunteers at the ultrahigh field of 7 T with a prototype four-channel radiofrequency coil array, in comparison with 3-T imaging of the same subjects. Signal-to-noise ratios at both field strengths were estimated using the rigorous Kellman method. Spinal cord cross-sectional area measurements were performed, including whole-cord measurements at both fields and gray matter segmentation at 7 T. The 7-T array coil showed reduced sagittal coverage, comparable axial coverage and the expected significantly higher signal-to-noise ratio compared with equivalent 3-T protocols. In the cervical spinal cord, the signal-to-noise ratio was found by the Kellman method to be higher by a factor of 3.5 with the 7-T coil than with standard 3-T coils. Cervical spine imaging in healthy volunteers at 7 T revealed not only detailed white/gray matter differentiation, but also structures not visualized at lower fields, such as denticulate ligaments, nerve roots and rostral-caudal blood vessels. Whole-cord cross-sectional area measurements showed good agreement at both field strengths. The measurable gray/white matter cross-sectional areas at 7 T were found to be comparable with reports from histology. These pilot data demonstrate the use of higher signal-to-noise ratios at the ultrahigh field of 7 T for significant improvement in anatomical resolution of the cervical spinal cord, allowing the visualization of structures not seen at lower field strength, particularly for axial imaging.
我们在 7T 超高场使用原型四通道射频线圈阵列,对健康志愿者的颈椎脊髓进行高分辨率解剖成像,并与相同受试者的 3T 成像进行比较。使用严格的 Kellman 方法估计两种场强下的信噪比。进行脊髓横截面积测量,包括在两种场强下的整个脊髓测量和 7T 时的灰质分割。7T 阵列线圈显示出矢状覆盖减少,与等效 3T 方案相比,轴向覆盖相当,预期信号噪声比显著更高。在颈椎脊髓中,通过 Kellman 方法发现,7T 线圈的信噪比比标准 3T 线圈高 3.5 倍。7T 健康志愿者颈椎成像不仅可以显示详细的白/灰质分化,还可以显示较低场强下无法显示的结构,如齿状韧带、神经根和头-尾血管。在两种场强下,全脊髓横截面积测量均显示出良好的一致性。在 7T 时可测量的灰质/白质横截面积与组织学报告相当。这些初步数据表明,在 7T 的超高场使用更高的信噪比可显著提高颈椎脊髓的解剖分辨率,允许观察到较低场强下无法看到的结构,特别是在轴向成像方面。