Department of System Control Engineering, Graduate School of Engineering, Tokushima Bunri University, 1314-1 Shido, Sanuki-city, Kagawa 769-2193, Japan; Department of Radiological Technology, Faculty of Health and Welfare, Tokushima Bunri University, 1314-1 Shido, Sanuki-city, Kagawa 769-2193, Japan; Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan.
Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, 5-11-80 Kodatsuno, Kanazawa, Ishikawa 920-0942, Japan; Department of Radiology, Otsu City Hospital, 2-9-9, Motomiya, Otsu-city, Shiga 520-0804, Japan.
Eur J Radiol. 2022 Apr;149:110202. doi: 10.1016/j.ejrad.2022.110202. Epub 2022 Feb 9.
We performed echo-planar imaging (EPI) and turbo spin-echo (TSE) diffusion-weighted imaging (DWI) using magnetic resonance imaging (MRI) to obtain basic clinical data of the apparent diffusion coefficient (ADC) in various parts of normal brains and compared the datasets using our retrospective distortion correction technique.
The normal brains of 32 patients who underwent health check were scanned on a 1.5-T MRI instrument using EPI- and TSE-DWI. Distortion was corrected by (1) segmentation: the b0 images were segmented based on the plural threshold values; (2) edge detection: the edge was detected in the images obtained in step (1); (3) non-rigid image registration: non-rigid image registration using Demons algorithm was achieved between the b0 images of EPI-DWI and TSE-DWI, thereby, creating a displacement field; and (4) image warp: the displacement field was applied to the b1000 image to warp. Twenty-six parts of the brain were measured from the images of b0 and b1000 and the ADCs were calculated. The signal-to-noise ratio (SNR) of the cerebrospinal fluid was measured to identify the cause of the difference between the two sequences. These were compared using Wilcoxon signed-rank test (P = 0.05).
The ADC was significantly higher measured by EPI-DWI than by TSE-DWI. The SNR of EPI-DWI was significantly higher than that of the TSE-DWI.
Care must be taken when measuring ADCs near the base of the skull, such as the brain stem, where the SNR of the imaging technique is likely to decrease or distort.
我们使用磁共振成像（MRI）进行了 echo-planar 成像（EPI）和 turbo 自旋回波（TSE）扩散加权成像（DWI），以获得正常大脑各部位表观扩散系数（ADC）的基本临床数据，并使用我们的回顾性失真校正技术比较了这些数据集。
对 32 名接受健康检查的患者的正常大脑在 1.5-T MRI 仪器上进行了 EPI 和 TSE-DWI 扫描。通过以下步骤（1）分段：根据多个阈值对 b0 图像进行分段；（2）边缘检测：在步骤（1）中获得的图像中检测边缘；（3）非刚性图像配准：使用 Demons 算法在 EPI-DWI 和 TSE-DWI 的 b0 图像之间实现非刚性图像配准，从而创建位移场；以及（4）图像变形：将位移场应用于 b1000 图像以进行变形。从 b0 和 b1000 图像测量了 26 个脑区，并计算了 ADC 值。测量脑脊液的信噪比（SNR）以确定两个序列之间差异的原因。使用 Wilcoxon 符号秩检验（P=0.05）比较这些结果。
EPI-DWI 测量的 ADC 明显高于 TSE-DWI。EPI-DWI 的 SNR 明显高于 TSE-DWI。
在测量靠近颅底的 ADC 时，如脑干，必须注意成像技术的 SNR 可能会降低或失真。
