本文選題：磁共振彈性成像(MRE)　切入點：剪切模量　出處：《東北大學》2014年碩士論文

【摘要】：磁共振彈性成像(Magnetic Resonance Elastography, MRE)是一種利用磁共振成像技術(MRI)新型的無創(chuàng)成像方法,能直觀顯示和量化組織彈性。它是傳統(tǒng)觸診機器化、定量化的一種手段,客觀且分辨率高,不受診斷部位的限制,MRE圖像表達的是組織的生物力學特性參數,它能夠檢測體內組織在外部激勵機械波作用下產生的質點位移�，F(xiàn)在已經提出多種算法去確定物體的彈性性能,MRE面臨的一個挑戰(zhàn)性問題之一就是在重建剪切模量的圖像中,如何減少噪聲影響的同時并保持較高的對比度。所以在本文中,我們重點研究了磁共振彈性成像重建的相關算法。本文介紹了基于局部頻率估計的彈性圖重建算法,它有多種實現(xiàn)方式,傳統(tǒng)的實現(xiàn)方式是基于雙帶寬高斯濾波器,而本文使用了一個新的濾波器進行局部頻率估計,是對數正態(tài)正交小波,這也是本文的一個創(chuàng)新點,將我們提出的新方法與傳統(tǒng)方法用Matlab平臺實現(xiàn)并進行分析比較,結果證明使用對數正態(tài)正交小波得到的彈性圖分辨率比傳統(tǒng)方式高。接著本文又介紹了基于微分反演算法的磁共振彈性重建算法,因微分反演法的實現(xiàn)需要對相位位移數據進行平滑和二階微分的計算,為了同時實現(xiàn)上述兩個要求,本文選用Savitzky-Golay濾波器進行實現(xiàn),它是一種實用性很強,除噪效果非常好的濾波器。將微分反演算法與局部頻率估計算法得到的彈性圖進行分析比較。最后本文又簡單介紹了一下磁共振彈性重建的另一種方法剪切模量分解法,重點介紹了其原理和推導過程。
[Abstract]:Magnetic Resonance elasticity imaging (MREs) is a new noninvasive imaging method using magnetic resonance imaging (MRI), which can directly display and quantify tissue elasticity. It is a method of traditional palpation machine and quantification, which is objective and has high resolution. The MRE images, which are not restricted by the location of diagnosis, express the biomechanical characteristic parameters of the tissue. It can detect the displacement of particles caused by external mechanical waves. Now many algorithms have been proposed to determine the elastic properties of the body. One of the challenges for MRE is to reconstruct the image of shear modulus. How to reduce the noise effect while maintaining high contrast. Therefore, in this paper, we focus on the relevant algorithms of MRI reconstruction. In this paper, we introduce an elastic image reconstruction algorithm based on local frequency estimation. There are many ways to realize it. The traditional way is based on double bandwidth Gao Si filter. In this paper, a new filter is used to estimate the local frequency, which is the logarithmic normal orthogonal wavelet, which is also an innovation of this paper. The new method proposed by us is implemented with Matlab platform and compared with the traditional method. The results show that the resolution of the elastic image obtained by using logarithmic normal orthogonal wavelet is higher than that of the traditional method. Then, an elastic reconstruction algorithm of magnetic resonance based on differential inversion algorithm is introduced in this paper. The realization of differential inversion method requires smooth and second-order differential calculation of phase displacement data. In order to realize the above two requirements simultaneously, Savitzky-Golay filter is chosen to implement it, which is very practical. The differential inversion algorithm and the local frequency estimation algorithm are analyzed and compared with the elastic graph obtained by the local frequency estimation algorithm. Finally, another method of shear modulus decomposition for magnetic resonance elastic reconstruction is briefly introduced in this paper. The principle and derivation process are emphatically introduced.
【學位授予單位】：東北大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：R445.2

【參考文獻】

相關期刊論文 前1條

1 汪紅志;劉翔;王鶴;陳珊珊;黃清明;王曉琰;陸倫;黃勇;程紅巖;李鯁穎;張學龍;;磁共振彈性成像技術在肝纖維化檢測中的研究[J];波譜學雜志;2013年02期

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本文編號：1692566