超高速磁振造影技術之研究: 以多截面射頻脈衝激發之 平行磁振成像系統

Parallel Imaging with Simultaneous Multiple Slice RF Pulse Excitation

葉俊傑(Chun-Chieh Yeh)

指導教授 ： 陳志宏

共同指導教授 ： 姚晶

國立臺灣大學/電機資訊學院/電機工程學研究所/碩士(2004年)

https://doi.org/10.6342/NTU.2004.10378

摘要

摘要

關鍵詞：超高速磁振造影；多截面射頻脈衝激發；平行磁振成像

由於核磁共振影像技術(Magnetic Resonance Imaging)的非侵入性及多樣化的組織影像對比機制，已廣泛被運用在臨床醫學診斷及功能性影像研究，為了能即時得到動態影像，需要越來越高時間解析度，所以發展平行磁振成像技術(Parallel Imaging)來突破目前成像速度限制是相當重要課題。
研究動機是簡化同步多截面射頻激發脈衝(Simultaneous Multi Slice RF pulse Excitation)設計及分離方法，並結合平行磁振成像敏感度編碼技術（Sensitivity Encoding）平行重建影像。
設計2,3,4個同步多截面射頻激發脈衝及混合截面分離方法經過仿體驗證。另外以敏感度空間分佈關係將多截面激發混合截面分離；在平行影像重建部分導入規範化（Regularization）減輕雜訊擴大情形，增進運算過程穩定性。
在台大Bruker 3T機器上，以體線圈激發同步雙截面脈衝搭配雙通道心臟陣列線圈接收，達到增加四倍時間解析度。
未來將結合高溫超導高信雜比陣列線圈，渦型電流補償系統並且最佳化掃瞄參數，以期能將核磁造影成像速度增加一個數量級，並期待未來在功能性影像及生醫分子影像研究做出貢獻。

關鍵字

多截面射頻脈衝激發 ； 平行磁振成像 ； 超高速磁振造影

並列摘要

Abstract

Keywords： Simultaneous Multi Slice RF pulse Excitation；
Ultrafast MRI；Parallel Imaging

MRI (Magnetic Resonance Imaging) has been used in clinical diagnosis and scientific research because of its non-invasive and variety of tissue contrast mechanism . In order to get dynamic image in real time, temporal resolution should be improved . So it is important to break through the present speed limitation of magnetic resonance.
Our research focus on the development of Simultaneous Multi Slice RF pulse Excitation to raise the frequency band efficiency and combined with sensitivity encoding.
Simultaneous Multi Slice RF pulse Excitation and mixed slices separation has been verified on phantom and fruit.We also use multicoil arrays for separation of signal from multiple slices simultaneously excited;Tikhonov regularization was introduced to mitigate the noise amplification in SENSE reconstruction.
The result of our study established on NTUEE Bruker 3T,we use body coil to excite duoslice RF pulse and received by two channel cardiac phased array.The temporal resolution was improved four times.
With high temperature superconductive coil array,eddy current compensation,spiral pulse sequence and optimized scanning parameter,we expect to enhance one order of MRI acquisition. Futhermore, this result is applied on micro-image, and genome image.

並列關鍵字

Parallel Imaging ； Simultaneous Multi Slice RF pulse Excitation ； Ultrafast MRI

參考文獻

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