發(fā)布時(shí)間：2018-05-26 16:28

  本文選題：彌散張量 + 磁共振　； 參考：《浙江大學(xué)》2014年碩士論文

【摘要】：生物體的組織結(jié)構(gòu)會(huì)對(duì)其中的水分子彌散運(yùn)動(dòng)造成影響,反過(guò)來(lái)水分子的彌散運(yùn)動(dòng)反映了所處位置的組織特性。彌散張量磁共振成像(DT-MRI)在磁共振成像的基礎(chǔ)上利用多于六個(gè)的非線性相關(guān)方向梯度磁場(chǎng)檢測(cè)組織內(nèi)水分子在這些方向上的彌散速率,在此基礎(chǔ)上計(jì)算出水分子的彌散張量,用以研究這些組織內(nèi)部的精細(xì)結(jié)構(gòu)。當(dāng)前DT-MRI技術(shù)被廣泛地應(yīng)用于研究腦白質(zhì)神經(jīng)纖維,而較少涉及心臟領(lǐng)域。 心臟疾病的高發(fā)使得對(duì)心臟結(jié)構(gòu)特征與疾病的發(fā)病機(jī)理的研究變得越發(fā)迫切。與腦圖像剛性特征不同,心臟處于永不停歇的運(yùn)動(dòng)狀態(tài),這使得利用心臟圖像進(jìn)行疾病的診斷嚴(yán)重依賴于醫(yī)生的經(jīng)驗(yàn)和專業(yè)知識(shí),所得結(jié)果也有較大誤差。為更好地對(duì)比不同心臟彌散張量圖像所反映的信息從而為診斷提供強(qiáng)有力的支撐,就需要對(duì)心臟彌散張量進(jìn)行配準(zhǔn),從而使其達(dá)到空間對(duì)準(zhǔn)。 心臟的收縮、舒張是一個(gè)復(fù)雜的不規(guī)則運(yùn)動(dòng),這種不規(guī)則性使處于不同狀態(tài)的兩個(gè)心臟之間存在較大的形變。單純利用參數(shù)模型,如剛性變換、仿射變換、投影變換都不能很好地描述兩者之間的這種差異。心臟各部位的形變程度不同使得對(duì)心臟圖像的配準(zhǔn)需要分解為局部區(qū)域。為此,本文利用基于B樣條的自由變換模型來(lái)對(duì)局部差異進(jìn)行描述,得到局部范圍內(nèi)的形變場(chǎng),通過(guò)挨個(gè)地進(jìn)行局部配準(zhǔn)達(dá)到最終的配準(zhǔn)目的。為了在配準(zhǔn)精度與速度之間取得平衡,本文使用金字塔模型將整個(gè)的配準(zhǔn)分割為一個(gè)由粗到精的過(guò)程,提高了配準(zhǔn)的精度和速度。 得到配準(zhǔn)結(jié)果后,使用保持主向量方向PPD策略對(duì)張量進(jìn)行重定向以使張量主向量的方向與所在位置的周圍組織方向保持一致。 本文使用這種方法對(duì)心臟的二維彌散張量圖像進(jìn)行了配準(zhǔn)獲得了比較好的結(jié)果,并為將來(lái)進(jìn)一步的研究打下了基礎(chǔ)。
[Abstract]:The tissue structure of the organism will affect the diffusion of water molecules, which in turn reflects the tissue characteristics of the water molecules. Diffusion Zhang Liang Magnetic Resonance Imaging (DT-MRI) on the basis of magnetic resonance imaging, the diffusion rate of water molecules in these directions is measured by using more than six nonlinear correlation gradient magnetic fields, and the diffusion Zhang Liang of water molecules is calculated on this basis. Used to study the fine structure of these tissues. At present, DT-MRI technique is widely used to study white matter nerve fibers, less involved in the field of heart. The high incidence of heart disease makes it more urgent to study the structure and pathogenesis of heart disease. Unlike the rigid features of brain images, the heart is in a state of unceasing motion, which makes the diagnosis of diseases by using cardiac images rely heavily on the experience and professional knowledge of the doctors, and the results also have a large error. In order to better compare the information reflected in different diffused Zhang Liang images and provide strong support for diagnosis, it is necessary to register the cardiac diffused Zhang Liang to achieve spatial alignment. The contraction and relaxation of the heart is a complex irregular movement, which causes a large deformation between two hearts in different states. Simply using parametric models such as rigid transformation affine transformation and projection transformation can not well describe the difference between them. The degree of deformation in different parts of the heart makes the registration of the heart image need to be decomposed into local regions. In this paper, a free transformation model based on B-spline is used to describe the local difference, and the deformation field in the local range is obtained, and the final registration is achieved by local registration one by one. In order to achieve a balance between registration accuracy and speed, the pyramidal model is used to divide the whole registration into a coarse to fine process, which improves the accuracy and speed of registration. After the registration results are obtained, the Zhang Liang is redirected by using the PPD strategy to keep the direction of the principal vector so that the direction of the principal vector of the Zhang Liang is consistent with the direction of the surrounding tissue in the position. In this paper, this method is applied to the registration of two-dimensional diffused Zhang Liang images of the heart, and a good result is obtained, which will lay a foundation for further research in the future.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：R445.2

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 羅述謙,呂維雪;醫(yī)學(xué)圖像配準(zhǔn)技術(shù)[J];國(guó)外醫(yī)學(xué).生物醫(yī)學(xué)工程分冊(cè);1999年01期

，

本文編號(hào)：1937995