中風大鼠腦部梗塞體積比例和萎縮體積比例的計算

Abstract

According to recent research, stroke is one of the main causes of death as well as a source of massive economic burden that has concerned many researchers to work in the field of stroke research. Stroke is a cerebrovascular disease mainly divided into two types: ischemic stroke and hemorrhagic stroke, which refers to the partial blockage or bleeding inside blood vessels of the brain respectively. Both types of stroke lead to nutrient and oxygen deprivation in the brain, which ultimately cause brain damage or death. This study focused on ischemic stroke by using rats with middle cerebral artery occlusion (MCAO) as experimental subjects, and examining the images of their brains obtained from staining with 2, 3, 5-triphenyl tetrazolium chloride (TTC). The stroke rat brain infarct volume and atrophy volume computation system (SRBIAVC system) segmented the images via methods of background removal, gamma correction, brain center line detection, and genetic algorithm to yield a correct estimate on the volume of brain infarct and atrophy. This way, the SRBIAVC system can provide useful information in the development of new drugs for stroke treatment. In this study, the volume of infarct and atrophy was calculated based on 168 images of brain slices segmented from 28 original images of rat brains. As indicated by the experimental results, the estimates obtained by the SRBIAVC system were better than those by other methods and more closely approximated the estimates by experts.近年來的研究顯示，中風是造成死亡的主要殺手之一，同時也造成很大的經濟負擔，因此已有許多學者投入中風領域的研究。腦中風又稱為腦血管疾病，主要為兩大類，缺血型和出血型，分別是於腦血管內部產生局部性的阻塞或出血，造成腦部缺乏養分及氧氣而導致腦損傷或死亡。 本研究主要以缺血型中風為研究對象，針對中大腦動脈阻塞的大鼠為實驗對象，並以經2，3，5—氯化三苯基四氮唑染色的原始大鼠腦袋影像為研究影像。中風大鼠腦部梗塞和萎縮體積計算系統透過去背、伽碼校正、腦袋中線偵測、基因演算法等方法，來進行影像切割，並在最後正確地估算出梗塞和萎縮體積，讓此系統可以達到輔助中風藥物開發之目的。 本研究由28張的原始大鼠腦袋影像，切割出168張鼠腦切片區塊影像，並由這些影像來計算出梗塞和萎縮體積，實驗結果表明，中風大鼠腦部梗塞和萎縮體積計算系統所計算出梗塞和萎縮體積，比其他方法更來的優秀，且與專家所計算的結果也較為相近。摘要.........................i Abstract....................ii List of Contents............iii List of Figures.............iv List of Tables..............vi Chapter1.Introduction.......1 Chapter2.Related work.......6 2.1 Gamma correction........7 2.2 Local gamma correction..8 2.3 Otsu's threshold method.10 2.4 Mathematical morphology.12 2.4.1 Erosion and dilation..12 2.4.2 Opening and closing...13 2.5 Evaluation methods......14 Chapter3.SRBIAVC system.....15 3.1 Calculating the Infarct and Atrophy Regions in the Rat Brain.....15 3.1.1 Capturing the Brain Slice regions from Rat Brain Images.....15 3.1.2 Detecting the Center Line of RBS Regions..18 3.1.3 Identifying the Infarct Region..23 3.1.4 Identifying the Corpus Callosum...27 3.1.5 Removing the Corpus Callosum from Infarct Region.31 3.1.6 Calculating the Infarct Volume and Atrophy Volume32 3.2 Determining Parameters Based on Genetic Algorithm..33 3.2.1 Genetic Algorithm based Parameters Detector..34 3.2.2 The Parameters for Center line Detection...37 3.2.3 The Parameters for Corpus Callosum...38 Chapter4.Experimental Results...40 4.1 Capturing the Brain Slice regions from Rat Brain Images...40 4.2 Center line Detection...43 4.3 Infarct Region Identification....45 4.4 Corpus Callosum Identification..48 4.5 Infarct Region Identification after Corpus Callosum Removal...50 4.6 Infarct and Atrophy Volume Calculation..55 Chapter5.Conclusions....59 Reference...............6