• The Korean Journal of Nuclear Medicine
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• v.39 no.2
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• pp.75-81
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• 2005

Myocardial perfusion and function can be quantified using SPECT and PET. There was controversy over the usefulness of the correction techniques for physical artifacts, such as photon attenuation and scatter, in the quantification of myocardial perfusion using SPECT. However, the cumulated results of many investigations have leaded the consensus on the usefulness of the correction procedures to improve the accuracy and specificity of the myocardial SPECT in the assessment of coronary artery diseases. Although the clinical value of the myocardial perfusion PET has not been preyed yet, the absolute myocardial blood flow and perfusion reserve values quantified using myocardial PET are employed in many basic investigations. In this paper, the methods for the quantitative myocardial SPECT and PET will be reviewed.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.3
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• pp.207-214
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• 2009

Positron emission tomogrpahy (PET) represents the most advanced scintigraphic imaging technology. With the increase in availability of PET, the clinical use of PET has grown in medical fields. This can be employed for cardiovascular research as well as for clinical applications in patients with various cardiovascular disease. PET allows non-invasive functional assessment of myocardial perfusion, substrate metabolism and cardiac innervation and receptors as well as gene expression in vivo. PET is regarded as the gold standard for the detection of myocardial viability, and it is the only method available for the quantitative assessment of myocardial blood flow. This review focuses on the clinical applications of myocardial perfusion PET in coronary artery disease.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.223-230
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• 1995

This study investigates a combined mathematical model for the quantitative estimation of regional myocardial blood flow in experimental canine coronary artery occlusion and in patients with ischemic myocardial diseases 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. Thirty four Rb-82 dynamic myocardial PET scans were performed sequentially for each experiment using our 5, 10 and 20 second acquisition protocol, respectively, and six to seven regions of interest were drawn on each transaxial slices, one on left ventricular chamber for input function and the others on normal and decreased perfusion myocardial segments for the flow estimation in those regions. Two compartment model and graphical analysis method have been applied to the measured sets of regional PET data, and the rate constants of influx to myocardial tissue were calculated for regional myocardial flow estimates with the two parameter fits of raw data by the Levenberg-Marquardt method. The results showed that, (I) two compartment model suggested by Kety-Schmidt, with proper modification of the measured data and volume of distribution, 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 in previously used graphical analysis, and (3) mathematically fitted input and tissue time activity curves were more suitable than the direct application of the measured data in terms of convergence.

• The Korean Journal of Nuclear Medicine
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• v.39 no.2
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• pp.133-140
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• 2005

The potential for recovery of left ventricular dysfunction after myocardial revascularization represents a practical clinical definition for myocardial viability. The evaluation of viable myocardium in patients with severe global left ventricular dysfunction due to coronary artery disease and with regional dysfunction after acute myocardial infarction is an important issue whether left ventricular dysfunction may be reversible or irreversible after therapy. If the dysfunction is due to stunning or hibernation, functional improvement is observed. but stunned myocardium may recover of dysfunction with no revascularization. Hibernation is chronic process due to chronic reduction in the resting myocardial blood flow. There are two types of myocardial hibernation: "functional hibernation" with preserved contractile reserve and "structural hibernation" without contractile reserve in segments with preserved glucose metabolism. This review focus on the application of F-18 FDG and other radionuclides to evaluate myocardial viability. In addition the factors influencing predictive value of FDG imaging for evaluating viability and the different criteria for viability are also reviewed.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.33-37
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• 2010

Purpose: In the early stage of using PET/CT, it was used to damper revision but recently shows that CT with MDCT is commonly used and works well for an anatomical diagnosis. This hospital makes the accuracy and convenience more higher in the diagnosis and evaluate of coronary heart disease through concurrently running myocardial perfusion SPECT examination, myocardial PET examination with FDG, and CT coronary artery CT angiography(coronary CTA) used PET/CT with 64-slice. This report shows protocol and image based on results from about 400 coronary heart disease examinations since having 64 channels PET/CT in July 2007. Materials and Methods: An Equipment for this examination is 64-slice CT and Discovery VCT (DVCT) that is consisted of PET with BGO ($Bi_4Ge_3O_{12}$) scintillation crystal by GE health care. First myocardial perfusion SPECT with pharmacologic stress test to reduce waiting time of a patient and get a quick diagnosis and evaluation, and right after it, myocardial FDG PET examination and coronary CTA run without a break. One-stop evaluation protocol of ischemic heart disease is as follows. 1)Myocardial perfusion SPECT with pharmacologic stress: A patient is injected with $^{99m}Tc$-MIBI 10 mCi and does not have any fatty food for myocardial PET examination and drink natural water with ursodeoxcholic acid 100 mg and we get SPECT image in an hour. 2)Myocardial FDG PET: To reduce blood fatty content and to increase uptake of FDG, we used creative oral glucose load using insulin and Acipimox to according to blood acid content. A patient is injected with $^{18}F$-FDG 5 mCi for reduction of his radiation exposure and we get a gated image an hour later and get delay image when we need. 3) Coronary CTA: The most important point is to control heart rate and to get cooperation of patient's breath. In order to reduce a heart rate of him or her below 65 beats, let him or her take beta blocker 50 mg ~ 200 mg after a consultation with a doctor about it and have breath-practices then have the examination. Right before the examination, we spray isosorbide dinitrate 3 to 5 times to lower tension of bessel wall and to extension a blood wall of a patient. It makes to get better the shape of an anatomy. At filming, a patient is injected CT contrast with high pressure and have enough practices before the examination in order to have no problem. For reduction of his radiation exposure, we have to do ECG-triggered X-ray tube modulation exposure. Results: We evaluate coronary artery stenosis through coronary CTA and study correlation (culprit vessel check) of a decline between stenosis and perfusion from the myocardial perfusion SPECT with pharmacologic stress, coronary CTA, and can check viability of infarction or hibernating myocardium by FDG PET. Conclusion: The examination makes us to set up a direction of remedy (drug treatment, PCI, CABG) because we can estimate of effect from remedy, lesion site and severity. In addition, we have an advantage that it takes just 3 hours and one-stop in that all of process of examinations run in succession and at the same time. Therefore it shows that the method is useful in one stop evaluation of ischemic heart disease.

• The Korean Journal of Nuclear Medicine
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• v.29 no.1
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• pp.48-53
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• 1995

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 myocardial 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 suitable than the direct application of the measured data in terms of convergence.

• The Korean Journal of Nuclear Medicine
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• v.39 no.2
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• pp.118-123
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• 2005

Positron emission tomography (PET) serves as a gold standard for noninvasive in vivo measurement of myocardial blood flow (MBF) and coronary flow reserve (CFR). CFR can be defined as the ratio of maximally vasodilated MBF over its basal flow. It is an important parameter for the evaluation of functional severity of coronary stenosis and prognositification in various diseases such as dilated cardiomyopathy. $^{13}NH_3,\;H_2^{15}O,\;^{82}Rb$ are widely used radiopharmaceuticals for measuring MBF and CFR, This review introduces imaging techniques and its clinical utility. Cardiac application or PET and PET/CT is expected to be increased in near future.

• The Korean Journal of Nuclear Medicine
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• v.35 no.6
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• pp.398-400
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• 2001

The authors report a case of unsuspected myocardial ischemia detected during CoDe FDG PET (coincidence detection fluorodeoxyglucose positron emission tomogram) which was performed for the evaluation of a solitary pulmonary nodule. Camera-based FDG PET without attenuation correction often reveals false defect in the inferior wall of the left ventricle in normals due to excessive attenuation. However, this asymptomatic patient had increased uptake in the inferior wall suggesting ischemic myocardium. The scan finding was confirmed by Tl-201 myocardial SPECT and coronary angiogram. The patient then underwent successful PTCA of mild RCA and right ventricular branch followed by right upper lobectomy for small cell lung cancer.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.5
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• pp.354-361
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• 2008

Purpose: N-13 ammonia uptake and retention in the myocardium is related to perfusion and metabolism. There are several potential advantages of N-13 ammonia positron emission tomography (PET) to detect myocardial ischemia, such as higher spatial resolution, greater counting efficiencies, and robust attenuation correction. But there are few reports comparing Tc-99m myocardial perfusion single photon emission tomography (MPS) and N-13 ammonia PET. We thus compared adenosine stress N-13 ammonia PET/CT and Tc-99m sestamibi MPS in patients with suspected coronary artery stenosis. Materials and Methods: Seventeen patients (male 13 : $63{\pm}11$ years old) underwent adenosine stress N-13 ammonia PET/CT (Discovery ST, GE), Tc-99m sestamibi MPS (dual head gamma camera, Hawkeye, GE) and coronary angiography within 1 week. N-13 ammonia PET/CT and Tc-99m sestamibi MPS images were assessed with a 20-segment model by visual interpretation and quantitative analysis using automatic quantitative software (Myovation, GE). Results: Both sensitivities and specificities of detecting an individual coronary artery stenosis were higher for N-13 ammonia PET/CT than Tc-99m sestamibi MPS (PET/CT: 91%/89% vs MPS: 65%/82%). N-13 ammonia PET/CT showed reversibility in 52% of segments that were considered non-reversibile by Tc-99m sestamibi MPS. In the 110 myocardial segments supplied by the stenotic coronary artery, N-13 ammonia PET/CT showed higher count densities than Tc-99m MPS on rest study (p < 0.01), and the difference of count density between the stress and the rest studies was also larger on N-13 ammonia PET/CT. Conclusion: Adenosine stress N-13 ammonia PET/CT had higher diagnostic sensitivity and specificity, more reversibility of perfusion defects and greater stress/rest uptake differences than Tc-99m sestamibi MPS. Accordingly, N-13 ammonia PET/CT might offer better assessment of myocardial ischemia and viability.

• The Korean Journal of Nuclear Medicine
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• v.38 no.3
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• pp.218-224
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• 2004

We compared rest perfusion PET with redistribution perfusion SPECT to investigate the concordant rate between PET and SPECT images and analyze the discordant pattern. Materials and Methods: Rest N-13 ammonia and F-18 FDG PET were performed on 18 patients with old myocardial infarction and left ventricular dysfunction whose dipyridamole - 4hr redistribution TI-201 SPECT showed one or more severe fixed defects. Regional perfusion and metabolism were evaluated visually and quantitatively with 5-segment myocardial model. Results: There were high concordant rate in uptake pattern (80/90 segments, 88.9%) and high correlation coefficient on quantitative analysis (R=0.81, p<0.001) between redistribution TI-201 SPECT and N-13 ammonia PET images. Nine of 18 patients had SPECT-PET concordant pattern (Group I). Ten segments (9 in inferior wall, 1 in apex) from the remaining 9 patients showed SPECT-PET discordant pattern with abnormal TI-201 defect and near normal N-13 ammonia uptake (Group II). The diastolic and systolic left ventricular dimensions were significantly increased in Group II compared to those of Group I. When attenuation uncorrected N-13 ammonia PET images were reconstructed in Group II, it resulted in PET images with severe inferior wall defects nearly identical to those seen in redistribution TI-201 SPECT images. Conclusion: Redistribution TI-201 SPECT images showed high concordant rate and correlation with rest N-13 ammonia PET images. Most of discordant segments had fixed thallium defects in inferior wall with nearly normal N-13 ammonia uptake, which may result from severe left ventricular dilatation and attenuation by the left hemidiaphragm and cardiac blood pool.