2014-05-012024-05-18https://scholars.lib.ntu.edu.tw/handle/123456789/701299摘要：在眾多現代醫學影像中，磁振造影 (Magnetic Resonance Imaging, MRI) 以非侵入性、無游離性輻射之方式，產生高空間解析度的腦部影像。其對於臨床醫學與基礎生物醫學研究的貢獻尤其重大。然而，在實際造影過程中，核磁共振影像的訊號頻率會因為核磁共振影像系統本身不穩定度或是成像物體(人體)的生理訊號或移動干擾而有所漂移，造成的後果是核磁共振訊號偏離共振頻率理論值的離共振現象(off-resonance)。傳統上要降低離共振現象的方式為對離共振的磁場進行”離磁場強度造影”(field mapping)。但是此一方式有許多限制: 包括(1)所求得的 field map 僅為具有片面資訊的一靜態影像。(2)求出之 field map 被認為與實驗進行時的離共振現象一致，然而實際上因機器不穩定度與生理動態變化影像，此一假設並不一定正確。(3)成像時間會因進行 field mapping 而拉長。 本計劃旨在研究發展尖端核磁共振影像硬體技術。具體而言，將研發與多通道核磁共振相列線圈整合之多通道量測核磁共振影像磁場偵測器(field probe)，並用以搭配各種脈衝程序在成像同時量測出高空間解析度的影像。此一硬體架構在本計劃初期將應用於動態功能性核磁共振影像(functional MRI)以瞭解人腦功能。<br> Abstract: Magnetic resonance imaging (MRI) has become an indispensible diagnostic tools in clinical medicine because of its non-invasiveness, non-ionized radiation energy source, ad high spatial resolution. However, the resonance frequency of a MRI system can drift over time. Further being contaminated by physiological noise and motion artifacts, MRI signal can be significantly degraded. These adverse effects can be all described by the off-resonance phenomena. Conventionally the off-resonance challenge can be partially mitigated by the combination of fielding mapping and image processing strategies. Such approaches are limited by the fact that 1) the mapped off-resonance field is stationary, while the disturbance can demonstrate a dynamic structure, 2) discrepancy between pulse sequences in field mapping and the experiment of interest, and 3) increased scanning time due to the field mapping procedure. This project aims at developing multi-channel field probe system, which will be used to dynamically monitor the field distribution without modifying the pulse sequence of the experiment of interest. Importantly, this field probe system will be integrated with multi-channel radio-frequency (RF) coil arrays in dynamic functional MRI (fMRI) of human brain.核磁共振影像射頻線圈相列線圈硬體磁場偵測器magnetic resonance imagingMR IRF coilradio-frequency coilhardwarephased arrayfield probe