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| DC 欄位 | 值 | 語言 |
|---|---|---|
| dc.contributor.advisor | 鍾孝文 | |
| dc.contributor.author | Shu-Fu Shih | en |
| dc.contributor.author | 石書輔 | zh_TW |
| dc.date.accessioned | 2021-06-17T01:36:25Z | - |
| dc.date.available | 2020-08-02 | |
| dc.date.copyright | 2017-08-02 | |
| dc.date.issued | 2017 | |
| dc.date.submitted | 2017-08-01 | |
| dc.identifier.citation | [1] Hahn EL. An accurate nuclear magnetic resonance method for measuring spin-lattice relaxation times. Phys Rev 1949; 76:145–146.
[2] Messroghli DR, Radjenovic A, Kozerke S, Higgins DM, Sivananthan MU, Ridgway JP. Modified Look-Locker inversion recovery (MOLLI) for high-resolution T1 mapping of the heart. Magn Reson Med 2004; 52: 141–146. [3] Homer J, Beevers MS. Driven-equilibrium single-pulse observation of T1relaxation. A re-evaluation of a rapid 'new' method for determining NMR spin-lattice relaxation times. J Magn Reson 1985; 63: 287–297. [4] Deoni SCL, Rutt BK, Peters TM. Rapid combined T1 and T2 mapping using gradient acquisition in the steady state. Magn Reson Med 2003; 49: 515–526. [5] Lingala SG, Jacob M. Blind compressive sensing dynamic MRI. IEEE Trans Med Imaging 2013; 32:1132. [6] Bhave S, Lingala SG, Johnson CP, Magnotta VA, Jacob M. Accelerated whole-brain multi-parameter mapping using blind compressed sensing. Magn Reson Med 2016; 75:1175–1186. [7] Haase A, Frahm J, Mattaei D, Hanicke W, Merboldt KD. FLASH imaging: rapid NMR imaging using low flip-angle pulses. J Magn Reson 1986: 67, 256–266. [8] Ernst RR, Anderson WA. Application of Fourier transform to magnetic resonance spectroscopy. Rev Sci Instrum 1966; 37: 93–98. [9] Hurley SA, Yarnykh VL, Johnson KM, Field AS, Alexander AL, Samsonov AA. Simultaneous variable flip angle-actual flip angle imaging method for improved accuracy and precision of three-dimensional T(1) and B(1) measurements. Magn Reson Med 2012; 68:54–64. [10] Deoni SCL. High-resolution T1 mapping of the brain at 3T with driven equilibrium single pulse observation of T1 with high-speed incorporation of RF field inhomogeneities (DESPOT1-HIFI). J Magn Reson Imaging 2007; 26: 1106–1111. [11] Cheng HL, Wright GA. Rapid high-resolution T1 mapping by variable flip angles: accurate and precise measurements in the presence of radiofrequency field inhomogeneity. Magn Reson Med 2006; 55: 566–574. [12] Deoni SC, Peters TM, Rutt BK. Determination of optimal angles for variable nutation proton magnetic spin-lattice, T1, and spin-spin, T2, relaxation times measurement. Magn Reson Med 2004; 51: 194–199. [13] Chang LC, Koay CG, Basser PJ, Pierpaoli C. Linear least-squares method for unbiased estimation of T1 from SPGR signals. Magn Reson Med 2008; 60:496–501. [14] Donoho D. Compressed sensing. IEEE Trans Inf Theory 2006; 52: 1289–1306. [15] Lustig M, Donoho DL, Pauly JM. Sparse MRI: the application of compressed sensing for rapid MR imaging. Magn Reson Med 2007; 58: 1182–1195. [16] Gleichman S, Eldar YC. Blind compressed sensing. IEEE Trans Inf Theory 2011; 57:6958–6975. [17] Lingala SG, Jacob M. A blind compressive sensing frame work for accelerated dynamic MRI. Proc. 9th IEEE Int. Symp Biomed Imag 2012, pp. 1060–1063. [18] Winkelmann S, Schaeffter T, Koehler T, Eggers H, Doessel O. An optimal radial profile order based on the Golden Ratio for time-resolved MRI. IEEE Trans Med Imaging 2007; 26:68–76. [19] Heule R, Ganter C, Bieri O. Variable flip angle T1 mapping in the human brain with reduced T2 sensitivity using fast radiofrequency-spoiled gradient echo imaging. Magn Reson Med 2016; 75:1413–1422. [20] Stikov N, Boudreau M, Levesque IR, Tardif CL, Barral JK, Pike GB. On the accuracy of T1 mapping: searching for common ground. Magn Reson Med 2015; 73:514–522. [21] Yarnykh VL. Optimal radiofrequency and gradient spoiling for improved accuracy of T1 and B1 measurements using fast steady-state techniques. Magn Reson Med 2010; 63:1610–1626. | |
| dc.identifier.uri | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/67533 | - |
| dc.description.abstract | 多激發角度T1圖譜是一種基於非平衡梯度回訊序列的T1定量方法，此方法利用多組來自不同激發角度的影像以準確估計T1，因此常需要在掃描時間及不同激發角度的數量上作權衡。本論文探討了利用盲壓縮感知以加速多激發角度T1圖譜的可行性，這種技術可以在不預先假設一組固定的基底函數之下，使用稀疏限制重建影像。我們使用真實大腦影像，運用後處理的方式比較不同取樣方式的結果並討論演算法參數的選擇。我們在初步的結果中展示了5倍加速後的定量T1圖譜，希望能提供此更快速的多激發角度T1圖譜實際應用時的參考。 | zh_TW |
| dc.description.abstract | Variable flip angle T1 mapping is a T1 quantification technique based on spoiled gradient echo (SPGR) sequence. This method requires multiple images at different flip angles for accurate T1 estimations, so a trade-off is often made between acquisition time and the number of flip angles. This thesis aims to investigate the feasibility of faster variable flip angle T1 mapping by incorporating blind compressed sensing. This technique used sparsity constraint to reconstruct images without the assumption of a fixed dictionary. We retrospectively subsample in vivo brain images and compare the results of quantitative T1 maps with a 5-fold acceleration and provide a reference for practical implementation of a faster variable flip angle T1 mapping. | en |
| dc.description.provenance | Made available in DSpace on 2021-06-17T01:36:25Z (GMT). No. of bitstreams: 1 ntu-106-R04945006-1.pdf: 3698043 bytes, checksum: efcad6e4b04105e160890c5e678de454 (MD5) Previous issue date: 2017 | en |
| dc.description.tableofcontents | 中文摘要 ……………… i
ABSTRACT ……………… ii CONTENTS ……………… iii LIST OF FIGURES ……………… v LIST OF TABLES ……………… vi Chapter 1 Introduction ……………… 1 Chapter 2 Theories ……………… 3 2.1 Spoiled gradient echo sequence ……………… 3 2.2 Variable flip angle T1 mapping ……………… 4 2.2.1 Linear and nonlinear fitting methods ……………… 4 2.2.2 Choices of flip angles and number of fitting points ……………… 6 2.3 Blind compressed sensing ……………… 6 2.3.1 Overview of compressed sensing ……………… 6 2.3.2 Concepts of blind compressed sensing ……………… 7 2.3.3 Optimization algorithm ……………… 9 2.3.4 Choices of parameters ……………… 12 Chapter 3 Material and Methods ……………… 13 3.1 In vivo data acquisition ……………… 13 3.2 Subsampling patterns ……………… 13 3.3 Blind compressed sensing parameters ……………… 17 3.4 Experiments design ……………… 18 Chapter 4 Results ……………… 20 4.1 Performance of different sampling schemes ……………… 20 4.2 Basis functions ……………… 31 4.3 Dictionary size and regularization parameters ……………… 33 4.4 T1 map results ……………… 36 Chapter 5 Discussion ……………… 39 5.1 Randomness in the subsampling patterns ……………… 39 5.2 Inaccuracies in variable flip angle T1 mapping ……………… 40 5.3 Applicability to 3D coverage ……………… 41 REFERENCES ……………… 42 | |
| dc.language.iso | en | |
| dc.subject | 多激發角度T1圖譜 | zh_TW |
| dc.subject | T1圖譜 | zh_TW |
| dc.subject | 壓縮感知 | zh_TW |
| dc.subject | 盲壓縮感知 | zh_TW |
| dc.subject | 取樣方式 | zh_TW |
| dc.subject | compressed sensing | en |
| dc.subject | T1 mapping | en |
| dc.subject | variable flip angle T1 mapping | en |
| dc.subject | sampling pattern | en |
| dc.subject | blind compressed sensing | en |
| dc.title | 應用盲壓縮感知加速多激發角度T1圖譜的可行性研究 | zh_TW |
| dc.title | Feasibility of Accelerated Variable Flip Angle T1 Mapping Using Blind Compressed Sensing | en |
| dc.type | Thesis | |
| dc.date.schoolyear | 105-2 | |
| dc.description.degree | 碩士 | |
| dc.contributor.oralexamcommittee | 劉華姍,林益如,吳文超,王福年 | |
| dc.subject.keyword | 多激發角度T1圖譜,T1圖譜,壓縮感知,盲壓縮感知,取樣方式, | zh_TW |
| dc.subject.keyword | variable flip angle T1 mapping,T1 mapping,compressed sensing,blind compressed sensing,sampling pattern, | en |
| dc.relation.page | 44 | |
| dc.identifier.doi | 10.6342/NTU201702362 | |
| dc.rights.note | 有償授權 | |
| dc.date.accepted | 2017-08-01 | |
| dc.contributor.author-college | 電機資訊學院 | zh_TW |
| dc.contributor.author-dept | 生醫電子與資訊學研究所 | zh_TW |
| 顯示於系所單位： | 生醫電子與資訊學研究所 | |
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| ntu-106-1.pdf 未授權公開取用 | 3.61 MB | Adobe PDF |
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