Department of Radiology, Columbia University Medical Center, New York, New York, USA.
Department of Radiology, Geisinger Medical Center, Danville, Pennsylvania, USA.
J Magn Reson Imaging. 2017 Sep;46(3):690-696. doi: 10.1002/jmri.25570. Epub 2016 Dec 26.
To validate the T1- and T2-weighted (T1w/T2w) MRI ratio technique in evaluating myelin in the neonatal brain.
T1w and T2w MR images of 10 term neonates with normal-appearing brain parenchyma were obtained from a single 1.5 Tesla MRI and retrospectively analyzed. T1w/T2w ratio images were created with a postprocessing pipeline and qualitatively compared with standard clinical sequences (T1w, T2w, and apparent diffusion coefficient [ADC]). Quantitative assessment was also performed to assess the ratio technique in detecting areas of known myelination (e.g., posterior limb of the internal capsule) and very low myelination (e.g., optic radiations) using linear regression analysis and the Michelson Contrast equation, a measure of luminance contrast intensity.
The ratio image provided qualitative improvements in the ability to visualize regional variation in myelin content of neonates. Linear regression analysis demonstrated a significant inverse relationship between the ratio intensity values and ADC values in the posterior limb of the internal capsule and the optic radiations (R = 0.96 and P < 0.001). The Michelson Contrast equation showed that contrast differences between these two regions for the ratio images were 1.6 times higher than T1w, 2.6 times higher than T2w, and 1.8 times higher than ADC (all P < 0.001). Finally, the ratio improved visualization of the corticospinal tract, one of the earliest myelinated pathways.
The T1w/T2w ratio accentuates contrast between myelinated and less myelinated structures and may enhance our diagnostic ability to detect myelination patterns in the neonatal brain.
2 Technical Efficacy: Stage2 J. MAGN. RESON. IMAGING 2017;46:690-696.
验证 T1 加权（T1w）/T2 加权（T2w）磁共振成像（MRI）比值技术在评估新生儿脑髓鞘中的作用。
从 10 名足月新生儿的单 1.5T MRI 中获得 T1w 和 T2w 磁共振图像，对这些图像进行回顾性分析。通过后处理管道创建 T1w/T2w 比值图像，并与标准临床序列（T1w、T2w 和表观扩散系数[ADC]）进行定性比较。还进行了定量评估，使用线性回归分析和米切尔逊对比度方程（一种亮度对比度强度的测量方法）来评估该比值技术在检测已知髓鞘化区域（如内囊后肢）和极低髓鞘化区域（如视辐射）的能力。
比值图像可提高对新生儿髓鞘含量的区域变化进行定性评估的能力。线性回归分析显示，在后肢和视辐射中，比值强度值与 ADC 值之间存在显著的负相关关系（R = 0.96，P < 0.001）。米切尔逊对比度方程显示，这两个区域的比值图像之间的对比度差异比 T1w 高 1.6 倍，比 T2w 高 2.6 倍，比 ADC 高 1.8 倍（均 P < 0.001）。最后，该比值图像改善了皮质脊髓束的可视化，皮质脊髓束是最早髓鞘化的通路之一。
T1w/T2w 比值可增强髓鞘化和少髓鞘化结构之间的对比度，可能提高我们检测新生儿脑髓鞘模式的诊断能力。
2 技术功效：阶段 2 J. MAGN. RESON. IMAGING 2017；46：690-696.
