本文選題：激光散斑成像 + 動靜脈分割��； 參考：《華中科技大學(xué)》2012年博士論文

【摘要】：了解腦組織不同成分在正常生理狀態(tài)下或者病理狀態(tài)下的動態(tài)響應(yīng),對研究神經(jīng)血管耦合機(jī)制、腦部疾病的診斷預(yù)防、藥物評估以及術(shù)中監(jiān)測等都有重大意義。激光散斑襯比成像技術(shù)以其簡單的成像系統(tǒng)、高時空分辨率、無需掃描的且非接觸的二維流速全場成像等特點(diǎn),在腦皮層功能研究、視網(wǎng)膜疾病和皮膚疾病的診斷和治療、藥物評價等領(lǐng)域的血流動態(tài)變化檢測中取得了重大應(yīng)用,是生命科學(xué)基礎(chǔ)研究和臨床診斷的重要工具。但是該技術(shù)本身不具備動靜脈分割能力,不能獨(dú)立的實(shí)現(xiàn)腦皮層不同成分的血流變化分析�；诠鈱W(xué)影像的動靜脈分割技術(shù)是提取組織不同成分的一個有效技術(shù)手段,對于基礎(chǔ)研究、臨床診斷、術(shù)中監(jiān)測等有很重大的意義。不過,目前的動靜脈分割技術(shù)和激光散斑襯比成像技術(shù)結(jié)合,會出現(xiàn)很多問題,比如降低系統(tǒng)時間分辨率、使成像系統(tǒng)結(jié)構(gòu)變得復(fù)雜。因此,本文對激光散斑數(shù)據(jù)所攜帶的信息進(jìn)行進(jìn)一步分析：通過分析激光散斑強(qiáng)度的分布,提出了基于單波長激光散斑相對最小反射率(Relative temporal minimum reflectance, RTMR)分析的動靜脈分割法,該方法具有簡單、自動以及準(zhǔn)確率高等優(yōu)點(diǎn)。該技術(shù)結(jié)合激光散斑襯比成像,在不改變激光散斑成像系統(tǒng)地前提下,實(shí)現(xiàn)了腦皮層不同組織成分獨(dú)立的血流變化分析。主要內(nèi)容如下： (1)提出一種自動有效的基于單波長激光散斑相對最小反射率分析的動靜脈分割法。襯比值比較小,并且CCD記錄的散斑圖像互相統(tǒng)計獨(dú)立時,Rayleigh分布函數(shù)是實(shí)際的積分散斑強(qiáng)度概率密度函數(shù)的一個很好的近似。通過Rayleigh分布函數(shù)得出激光散斑最小光強(qiáng)的表達(dá)式,發(fā)現(xiàn)它是平均光強(qiáng)和血流速度的整合參數(shù)。在激光散斑最小光強(qiáng)圖內(nèi),根據(jù)激光散斑最小光強(qiáng)值,對血管進(jìn)行分類。不過由于平均光強(qiáng)分布和入射光強(qiáng)有關(guān),因此激光散斑最小光強(qiáng)存在背景不均勻現(xiàn)象,為此引入激光散斑相對最小反射率這個參量�？臻g任意一點(diǎn)的激光散斑相對最小反射率定義為：該點(diǎn)的激光散斑最小光強(qiáng)除以該點(diǎn)在激光散斑時域內(nèi)均圖內(nèi)的鄰域的非血管腦皮層組織的平均光強(qiáng)。在RTMR圖中：動脈血管區(qū)域值最大；靜脈血管區(qū)域值相對最小,部分可能和非血管皮層區(qū)域重疊；非血管腦皮層區(qū)域的RTMR值在了兩類血管之間。為了避免誤判靜脈區(qū)域,所以先通過RTMR值采用多閾值法逐個像素的提取動脈網(wǎng)絡(luò)(即對于血管內(nèi)的一個像素,如果它的RTMR值比它的鄰域內(nèi)非血管腦組織像素的RTMR值平均值大,則該像素屬于動脈),然后從血管網(wǎng)絡(luò)圖中減去動脈結(jié)構(gòu),得出靜脈網(wǎng)絡(luò)。實(shí)驗(yàn)證明基于單波長激光散斑相對最小反射率分析的動靜脈分割法的準(zhǔn)確率高,動脈的PTR (True Positive rate)是98.5%,靜脈的PTR是95%,動脈的誤判率是1.5%,靜脈的誤判率是5%。同時分析了激光散斑相對最小反射率分析的有效波長,成像深度等參數(shù),其中最佳波長可能是600nm,成像深度大概是幾百微米。 (2)基于單波長激光散斑相對最小反射率分析的動靜脈分割法和激光散斑襯比成像技術(shù)結(jié)合,實(shí)現(xiàn)大鼠腦皮層不同成分組織在CSD模型中的獨(dú)自的血流變化分析。準(zhǔn)確地顯示了微小區(qū)域內(nèi),微動脈、微靜脈以及非血管腦皮層組織各自在CSD過程中的血流變化情況。
[Abstract]:It is of great significance to understand the dynamic response of different components of the brain under normal physiological or pathological conditions. It is of great significance for the study of the mechanism of the neurovascular coupling, the diagnosis and prevention of brain diseases, the evaluation of drugs and the monitoring of the operation. The non contact two-dimensional full field imaging is an important application in the research of cerebral cortex function, the diagnosis and treatment of the retina disease and the skin disease, the drug evaluation and so on. It is an important tool for the basic and clinical diagnosis of life science. However, the technique itself does not have the ability to divide the veins. The analysis of blood flow changes in different components of the cerebral cortex can not be realized independently. The technique of arteriovenous segmentation based on optical images is an effective technique for extracting different components of tissue. It is of great significance for basic research, clinical diagnosis, and intraoperative monitoring. However, the pre eye arteriovenous segmentation and laser speckle contrast imaging With the combination of technology, there will be many problems, such as reducing the time resolution of the system and making the structure of the imaging system complicated. Therefore, the information carried by the laser speckle data is further analyzed in this paper. By analyzing the distribution of laser speckle intensity, the relative minimum reflectivity (Relative temporal mini) based on the single wavelength laser speckle is proposed. Mum reflectance, RTMR) analysis of the method of arteriovenous segmentation. This method has the advantages of simple, automatic and high accuracy. This technique combines laser speckle contrast imaging and without changing the laser speckle imaging system, and realizes the analysis of the independent blood flow of different tissues in the cerebral cortex. The main contents are as follows:
(1) an automatic and effective dynamic vein segmentation method based on the relative minimum reflectance analysis of single wavelength laser speckle is proposed. When the contrast ratio is small, and when the CCD recorded speckle images are independent of each other, the Rayleigh distribution function is a good approximation of the actual intensity probability density function of the integral speckle intensity. The Rayleigh distribution function is obtained. The expression of the minimum light intensity of laser speckle shows that it is an integral parameter of the average intensity of light and the velocity of blood flow. The minimum intensity of laser speckle, Gon Jon Tu Hei, is classified according to the minimum intensity of laser speckle. However, the minimum intensity of the speckle is inhomogeneous due to the average intensity distribution and the incidence of the incident light intensity. The relative minimum reflectivity of the laser speckle is introduced. The minimum reflectance of the laser speckle at any point of space is defined as the minimum intensity of the laser speckle intensity divided by the mean light intensity of the non vascular cortical tissue in the neighbourhood of the laser speckle in the time domain of the laser speckle. In the RTMR diagram, the regional value of the arterial blood vessel is the largest; The regional values of venous vessels are relatively minimal and partially overlap with the non vascular cortex regions; the RTMR value of the non vascular cortical regions is between the two types of blood vessels. In order to avoid misjudging the venous area, the arterial network is extracted pixel by pixel by the multi threshold method by the RTMR value (that is, a pixel in the blood vessel, if its RTMR ratio is compared. " The average value of the RTMR value of the adjacent non vascular brain tissue is large, and the pixel belongs to the artery. Then the arterial structure is subtracted from the vascular network map and the vein network is obtained. The experimental results show that the accuracy of the arteriovenous segmentation based on the relative minimum reflectance analysis of single wavelength laser speckle is high, and the PTR (True Positive rate) of the artery is 98.5%, The PTR of the vein is 95%, the error rate of the artery is 1.5%, the error rate of the vein is 5%. and the effective wavelength of the relative minimum reflectance analysis of the laser speckle, the imaging depth and other parameters, of which the best wavelength may be 600nm, and the imaging depth is probably hundreds of microns.
(2) based on the combination of the single wavelength laser speckle relative minimum reflectivity analysis and the laser speckle contrast imaging technique, the individual blood flow changes in the CSD model of the rat cerebral cortex were analyzed. The microarteries, the venules and the non vascular cortical tissues were respectively in the CSD. The change of blood flow in the process.

【學(xué)位授予單位】：華中科技大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2012
【分類號】：R318.51

【引證文獻(xiàn)】

相關(guān)博士學(xué)位論文 前1條

1 武穎麗;粗糙目標(biāo)激光散斑統(tǒng)計特性及其微運(yùn)動檢測[D];西安電子科技大學(xué);2013年

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本文編號：1773248