指導教授：郭德盛臺灣大學：電機工程學研究所黃尹宬Huang, Yin-Cheng KrisYin-Cheng KrisHuang2014-11-282018-07-062014-11-282018-07-062014http://ntur.lib.ntu.edu.tw//handle/246246/262868漸變式驅動平衡方法為近十幾年來逐步發展的平衡穩定態自由旋進磁振影 像之變形。概念上，此版本的脈衝序列可分為兩部分：漸變式驅動平衡之磁化準 備時期以及隨後的固定傾角資料讀取時期。本論文作者於受試者實驗中發現：本 造影技術具有脂肪信號抑制的效果，前提為中央k 空間的資料來自暫態時期之影 像擷取。此外本技術呈現T2 權重影像對比。為分析這些影像特徵，我們採用程 式模擬及數學公式闡述，簡明呈現了在共振自旋與特定離共振自旋的時間演化行 為。我們另外募集了三十位健康受試者，測試漸變式驅動平衡技術作為超快速多 切面T2 權重腦部影像的可行性。為進行影像品質比較，我們亦採行了快速自旋 迴訊與快速梯度自旋迴訊兩種方法。我們也展示了幾位腦部病變患者的影像差異。 結果顯示：與其他兩種方法相比，漸變式驅動平衡方法大幅減少掃描時間與運動 假影干擾，但信噪比、灰質白質區分度、鐵質偵測等表現則較差。在如不自主運 動疾患等一些特殊臨床場合，漸變式驅動平衡技術有機會作為標準磁振造影方法 之外的替代方案。Transition into Driven Equilibrium (TIDE) balanced steady-state free precession (bSSFP) sequence is a variant of bSSFP MRI technique that has been developed over the last decade. The pulse sequence can be conceptually divided into two parts: a TIDE preparation and a repetitive constant flip angle readout. The authors of this thesis independently discovered fat suppression phenomenon during volunteer studies of TIDE bSSFP, when transient-phase data were sampled and registered at central k-space. In addition, this imaging method also shows a T2-weighted contrast. To analyze these specific properties, we used simulations and mathematical deduction to demonstrate concisely the evolution behaviors of on-resonance spins as well as certain off-resonance spins. We recruited thirty healthy volunteers to validate the image quality for TIDE bSSFP for use as an ultrafast multisection T2-weighted image of the brain. For image quality comparison, turbo spin echo (TSE) and turbo gradient spin-echo (TGSE) were also used. We also exhibited the differences between imaging methods on a few patients with brain pathologies. As a result, TIDE bSSFP provides T2-weighted images with reduced scan times and reduced motion artifact interference compared with TSE and turbo gradient spin-echo, with the trade-off of reduced SNR as well as poorer gray-white matter differentiation and iron load sensitivity. In certain situations like patients with involuntary motions, TIDE bSSFP technique may serve as a supplement to standard MRI methods.口試委員審定書 Acknowledgement 中文摘要 i Abstract ii Table of Contents iii Chapter 1 Introduction 1-1 1.1 Background of balanced steady-state free precession imaging 1-1 1.2 Off-Resonance spins and their influences on the bSSFP images 1-3 1.3 Transient phase phenomena in bSSFP imaging 1-6 Reference 1-8 Chapter 2 TIDE bSSFP: Another Catalyzation Method with A Different Contrast and Transient Off-Resonance Suppression 2-1 2.1 Catalyzing a smooth transition into the steady state using TIDE 2-1 2.2 Variable Contrasts from Different Strategies in TIDE 2-3 2.3 Discovery of The Fat Suppression Phenomenon of in our preliminary TIDE bSSFP studies 2-5 2.4 TIDE as A Fat-Suppression Preparation with Other Imaging Readout Modules 2-9 Reference 2-11 Chapter 3 Characterization of The Transient Off-Resonance Suppression Phenomenon 3-1 3.1 Simulations 3-1 3.1.1 Matrix operator formalism in magnetization evolutions 3-1 3.1.2 Simulation settings 3-4 3.1.3 Simulation results 3-5 3.2 Analytical Expression of Frequency-selective IR-like behaviors in TIDE bSSFP 3-10 3.3 Experimental Verification 3-14 3.3.1 Experimental settings 3-14 3.3.2 Experiment results 3-15 3.4 Discussion 3-18 Reference 3-21 Chapter 4 Clinical application: TIDE bSSFP as an Ultrafast Multisection T2-Weighted Imaging of the Brain 4-1 4.1 Image Experiments and Evaluation Methods 4-2 4.1.1 Healthy volunteers and patients with brain pathologies 4-2 4.1.2 Scanning protocols 4-3 4.1.3 Qualitative Analysis of Brain Imaging 4-4 4.1.4 Image Processing and Quantitative Data Analysis 4-5 4.1.5 Statistical Analysis 4-6 4.2 Image Results with Qualitative and Quantitative Analyses 4-7 4.2.1 Images acquired with the three imaging techniques 4-7 4.2.2 Results of Qualitative Analysis 4-11 4.2.3 Quantitative Analysis of Regional SNRs and CNRs 4-14 4.2.4 Images of Patients with Brain Pathologies 4-17 4.3 Discussion 4-22 Reference 4-28 Chapter 5 Conclusion 5-13712526 bytesapplication/pdf論文公開時間：2019/08/12論文使用權限：同意有償授權(權利金給回饋本人)磁振造影平衡穩定態自由旋進漸變式驅動平衡脂肪信號抑制T2權重影像thesishttp://ntur.lib.ntu.edu.tw/bitstream/246246/262868/1/ntu-103-F93921059-1.pdf