擴散張量影像法在人類腦組織之探討

The Evaluation Diffusion Tensor Imaging for Human Brain Tissue

聶伊辛(Yi-Hsin Nieh) ； 薛建宏(Jian-Hung Shiue) ； 李建穎(Gen-Ing Lee) ； 顏凡智(Fan-Ge Yen) ； 葉子成(Tzu-Chen Yeh) ； 莊奇容(Chi-Long Juang)

《中華放射線技術學雜誌》 28卷2期 (2004/12) Pp. 143-150

摘要

磁振造影(Magnetic Resonance Imaging, MRI)技術中的擴散加權影像(Diffusion Weighted imaging, DWI)法是目前臨床醫學上診斷急性腦梗塞的重要工具之一。由於腦組織的結構相當複雜，使得其內之水分子的擴散運動多呈非均向性。目前臨床的擴散加權影像法只能個別呈現單一方向和形跡的擴散影像，因而提出腦組織擴散張量影像法(Diffusion Tensor Image; DTI)研究。正常受試者的腦組織做非均向擴散實驗，使用的條件為：TR=2000 msec、TE=70 msec、△＝40 msec、δ=20 msec、FOV=28×28平方公分、切片厚度為10mm，用0；3；6；9 mT/m等四種不同的梯度強度，施加在讀出、相位、切面、讀出－相位、讀出－切片及相位－切片等六個方向，取24個影像進行ADC影像的重組。其結果所獲得的影像發現：腦組織的擴散受到物質本身成分或其結構走向所影響成非均向性。不同部位組織會因其水分子的走向不同，使得主要擴散方向不會固定在同一方向上。於是所獲得之擴散加權影像及外顯擴散係數(apparent diffusion coefficients, ADC)影像也會有所差異。目前最先進的應用是腦部的纖維追蹤，而此追蹤如果能與功能性磁振造影合併，也將為國內腦神經傳導開啟另一議題。

關鍵字

磁振擴散加權影像 ； 外顯擴散係數 ； 形跡 ； 張量

並列摘要

Diffusion-weighted Magnetic Resonance Imaging (MRI) is the most important clinical tools for the diagnosis of acute brain infarction. Due to the complex structure of the brain tissue, most diffusion mechanism of the brain water molecule is anisotropic. The DWI methods can only respectively take on single direction and diffusion trace images. Therefore, the research advances Diffusion Tensor Image of human brain tissue. Normal objectors' brain tissue makes anisotropic experiment, the study use condition for: TR=2000 msec, TE=70 msec, △＝40 msec, δ=20 msec, FOV=28×28 cm^2, slice thickness =10 mm, use 0; 3; 6; 9 mT/m different gradients intensity level, and direct to read, phase, slice, read-phase, read-slice and phase-slice six directions, and obtained 24 images to process ADC image's recombining. The result acquire: diffusion of brain tissue receive material in itself ingredient or it structure make for affect become anisotropic. Every tissue that water molecular content or make for different, diffusion intensity is not fixation at same direction. So, to acquire diffusion-weighted image and apparent diffusion coefficients (ADC) image can difference. Brain fiber tracing is now advancements application and this can combine functional MRI, the topic wills another act for nerves conduct of brain.

並列關鍵字

diffusion-weighted MR Imaging ； apparent diffusion coefficients ； trace ； tensor