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실험 개에서 Rb - 82 심근 Dynamic PET 영상을 이용한 국소 심근 혈류 예측의 기본 모델 연구
고창순(Chang Soon Koh),이명철(Myung Chul Lee),정준기(June Key Chung),이동수(Dong Soo Lee),서정돈(Joung Don Seo),정재민(Jae Min Jeong),곽철은(Cheol Eun Kwark),장기현(Kee Hyun Chang),강건욱(Keon Wook Kang),황은경(Eun Kyung Hwang) 대한핵의학회 1995 핵의학 분자영상 Vol.29 No.1
N/A This study investigates a simple mathematical model for the quantitative estimation of regional myocardial blood flow in experimental canine coronary artery thrombosis using Rb-82 dynamic myocardial positron emission tomography. The coronary thrombosis was induced using the new catheter technique by narrowing the lumen of coronary vessel gradually, which finally led to partial obstruction of coronary artery. Ten Rb-82 dynamic myocardial PET scans were performed sequentially for each experiment using our 5, 10% and 20 second acquisition protocol, respectively, and three regions of interest were drawn on the transaxial slices, one on left ventricular chamber for input function and the other two on normal and decreased perfusion segments for the flow estimation in those regions. Single compartment model has been applied to the measured sets of regional PET data, and the rate constants of influx to myocardial tissue were calculated for regional myocardia1 flow estimates with the three parameter fits of raw data by the Levenberg-Marquardt method. The results showed that, (1) single compartment model suggested by Kety-Schmidt could be used for the simple estimation of regional myocardial blood flow, (2) the calculated regional myocardial blood flow estimates were dependent on the selection of input function, which reflected partial volume effect and left ventricular wall motion, and (3) mathematically fitted input and tissue time activity curves were more suit-able than the direct application of the measured data in terms of convergence.
Tc - 99m - MIBI 심근 SPECT 영상에서 재구성 필터에 의한 인위적 관류결손에 관한 연구
고창순(Chang Soon Koh),이명철(Myung Chul Lee),정준기(June Key Chung),이동수(Dong Soo Lee),서정돈(Joung Don Seo),이경한(Kyung Han Lee),곽철은(Cheol Eun Kwark),박용우(Yong Woo Park) 대한핵의학회 1995 핵의학 분자영상 Vol.29 No.1
N/A Tc-99m-MIBI(Sestamibi) myocardial SPECT along with T1-201 tomographic imaging has demonstrated wide application and high image quality sufficient for the diagnosis of myocardial perfusion defect, which consequently reflects regional myocardial blood flow. The qualitative values of myocardial SPECT with Tc-99m-MIBI as well as the quantitative cases depend in some degree on the reconstruction techniques of multiple projections. Filtered backprojection(FBP) is the common standard for reconstruction rather than the complicated and time-consuming arithmetic methods. In FBP it is known that the distribution of radioactivity in reconstructed transverse slices varies with the selected filter parameters such as cutoff frequencies and order (Butterworth case). The cutoff frequencies basically remove and decrease the true radioactive distribution and alter the pixel counts, which lead to underestimation of true counts in specific myocardial regions. In this study, we have investigated the effect of cutoff frequencies of reconstruction filter on the artifactually induced perfusion defects, which are often demonstrated near inferior and/or inferoseptal cardiac walls due to the intense hepatic uptake of Tc-99m-MIBI. A computerized method for identifying the relative degree of artifactual perfusion defect and for comparing those degrees along with the relative amount of hepatic uptake to myocardium was developed and patient images were studied to observe the quantitative degree of underestimation of myocardial perfusion, and to propose some reasonable thresh-old of cutoff frequency in the diagnosis of perfusion defect quantitatively. We concluded that from the quantitative viewpoint cutoff frequencies may be used as high as possible with the sacrifice of homogeneity of image quality, and those frequencies lower than the common 0.3 Nyquist frequency would reveal severe degradation of radio-active distribution near inferior and/or inferoseptal myocardium when applying Butterworth or low pass filter.
관상동맥질환에서 Gated Blood Pool Scan 을 이용한 좌심실 확장기능의 분석
박영배,이영우,이명철,최창운,고창순,임상무,정준기,서정돈 대한핵의학회 1986 핵의학 분자영상 Vol.20 No.2
Resting gated blood pool scan was used to derive left ventricular functional changes in norrnals (N=13, mean age=43) and in patients with coronary artery disease (N=50, mean age=53). Peak filling rates, average filling rates, and ejection fractions were significantly depressed m coronary artery disease. (p $lt; 0.0005, each other). And in coronary artery disease with normal ejection fraction (N = 21), peak filling rates and average filling rates were depressed also, and peak filling rates of coronary artery disease with normal ejection fraction were abnormal in 61.2% and average fillin rates were abnormal in 71.4%. It appears that (1) resting peak filling rates and average filling rates were sensitive and easily obtainable pararneters of the diastolic dysfunction assosiated with coronary artery disease, (2) a significant proportion of coronary artery disease patients without any evidence of abnormal systolic function have depressed resting peak filling rates and average filling rates of the left ventricle.