• The Korean Journal of Nuclear Medicine
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• v.36 no.6
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• pp.381-391
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• 2002

Purpose: The presence of perfusion defect may influence the left ventricular mass (LVM) measurement by quantitative gated myocardial perfusion SPECT (QGS), and ischemic myocardium, usually showing perfusion defect may produce post-stress LV dysfunction. This study was aimed to evaluate the effects of extent and reversibility of perfusion defect on the automatic measurement of LVM by QGS and to investigate the effect of reversibility of perfusion defect on post-stress LV dysfunction. Subjects and Methods: Forty-six patients (male/female=34:12, mean age=64years) with perfusion defect on myocardial perfusion SPECT underwent rest and post-stress QGS. Forty patients (87%) showed reversible defect. End-diastolic volume (EDV), end-systolic volume (ESV), LV ejection fraction (EF), and LV myocardial volume were obtained from QGS by AutoQUANT program, and LVM was calculated by multiplying the LV myocardial volume by the specific gravity of myocardium. Results: LVMs measured at rest and post-stress QGS showed good correlation, and higher correlation was founded in the subjects with fixed perfusion defect and with small defect (smaller than 20%). There were no significant differences in EDVs, ESVs and EFs between obtained by rest and post-stress QGS un patients with fixed myocardial defect. Whereas, EF obtained by post-stress QGS was lower than that by rest QGS in patients with reversible defect and 10 (25%) of them showed decreases in EF more than 5% in post-stress QGS, as compared to that of rest QGS. Excellent correlations of EDVs, ESVs, EFs between rest and post-stress QGS were noted. Patients with fixed defect had higher correlation between EDVs, ESVs, EFs than patients with reversible defect. Conclusion: These results suggest that perfusion defect can affect LVM measurement by QGS and patients with reversible defect shows post-stress LV dysfunction more frequently than patients with fixed perfusion defect.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.231-238
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• 1995

Tc-99m-MIBI (Sestamibi) myocardial SPECT along with TI-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 ds the quantitative cases depend in some degree on the reconstruction techniques of multiple projections. Filtered backprojection (FBP) Is the common standard method 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 litter parameters such as cutoff frequencies and order (Butterworth case) The cutoff frequencies used in clinicAl practice partially 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 threshold 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 Wyquist frequency would reveal severe degradation of radioactive distribution near inferior and/or inferoseptal myocardium when applying Butterworth or low pass filter.

• The Korean Journal of Nuclear Medicine
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• v.27 no.2
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• pp.218-222
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• 1993

Lung/heart uptake ratio (L/H R) in $^{201}Tl$ myocardial perfusion scan is a reliable marker for long-term prognosis in patients with coronary artery disease. However, the value of L/H R in $^{99m}Tc-MIBI$ myocardial perfusion scan is controversial in determining the prognosis and severity of the coronary artery disease. The purpose of this study was to determine the clinical implications of L/H R in $^{99m}Tc-MIBI$ myocardial perfusion scan. Forty five patients who received $^{99m}Tc-MIBI$ myocardial perfusion scan were divided into control group and coronary artery disease (CAD) group by their clinical findings, EKGs, and $^{99m}Tc-MIBI$ myocardial perfusion scans. Twenty five patients in CAD group were divided into ischemic group and infarct group according to their results from $^{99m}Tc-MIBI$ myocardial perfusion scan. L/H R was calculated on the anterior planar view, 60 minutes after infusion of dipyridamole. Two regions of interest (ROI) were placed on the left lung area 8 pixel above the left ventricle and on the myocardial area which had the highest radioactivity. In the control group, there were no significant differences of L/H R according to sex and age. No significant difference of L/H R was found between the control and CAD group ($0.26{\pm}0.06,\;0.29{\pm}0.05$, p>0.05). In the CAD group, there was also no significant difference of L/H R between the ischemic group and infarct group ($0.29{\pm}0.07,\;0.30{\pm}0.04$, p>0.05). L/H R in CAD group did not show correlations with the defect area of stress polar map (r=0.18, p >0.05) and with the sum of severity weighted extent score or reversibility score which represent severity and extent of myocardial perfusion defect area in stress (r=0.18, p>0.05). We conclude that it is difficult to use L/H R as a marker for severity of CAD in dipyridamole $^{99m}Tc-MIBI$ myocardial perfusion scan.

• The Korean Journal of Nuclear Medicine Technology
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• v.16 no.2
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• pp.49-56
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• 2012

Purpose : Gated myocardial perfusion SPECT provides not only myocardial perfusion status, but various functional parameters of left ventricle (LV). The purpose of this study was to analyze ejection fraction (EF) for correlation and difference between $^{201}Tl$ gated myocardial perfusion SPECT and echocardiography depending on extent of perfusion defect, gender and LV volumes. Materials and Methods : From April 2011 to May 2012, we analyzed 291 patients (male:female =165:126; mean: $64.6{\pm}10.8$ years) who were examined both $^{201}Tl$ gated myocardial perfusion SPECT and echocardiography at less than 7 days apart in our hospital. 101 patients showed perfusion defect and the rest of the people without any defect. We applied automatic analysis (Quantitative gated SPECT, QGS), and calculated EF, End-diastolic volume (EDV) and End-systolic volume (ESV) from Stress (G-Stress) and Rest (G-Rest) studies. And we analyzed the correlation and difference for EF between $^{201}Tl$ gated SPECT and echocardiography. Results : The correlation of LVEF among G-Stress, G-Rest and echocardiography was quite a good (G-Stress vs. G-Rest: r=0.909, G-Stress vs. echocardiography: r=0.833, G-Rest vs. echocardiography: r=0.825). And there were significant differences in EDV, ESV and EF in total patients (p<0.01). The normal group showed significant difference in EF (p<0.01) and the group with perfusion defect also demonstrated significant difference (a group with reversible defect: p<0.01, fixed defect: p<0.01) depending on extent of perfusion defect. We analyzed difference in normal group by gender. In normal group, there was no significant difference (p>0.05) in EF from men. However, there was a significant difference (p<0.01) from women. When we classified two groups by average size of EDV in Korean women, there was no significant difference in a group of above average size of EDV (p>0.05). Conclusion : When compared among Stress and Rest of $^{201}Tl$ gated SPECT and echocardiography, we confirmed that there was a good correlation for LVEF. But there were significant differences among three studies. And extent of perfusion defect, gender and LV volumes are independent determinants of the accuracy of LVEF. So, it is hard to compare and interchange quantitative indices among modalities. We should take additional researches to prove results of our study.

• The Korean Journal of Nuclear Medicine
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• v.30 no.1
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• pp.104-111
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• 1996

We did Tc-99m sestamibi myocardial perfusion SPECT in 36 patients with acute myocardial infarction when they arrived at the emergency room. And we compared myocardial perfusion images with ECG findings. Then we obtained the follows. The myocardial infarction by the obstruction of left coronary descending artery and right coronary artery showed a good concordance in the diagnosis and infarction site between myocardial perfusion images and ECG findings. The 7 patients with myocardial infarction by a left circumflex coronary artery showed a perfusion defect in the lateral wall in myocardial perfusion SPECT images. But 4 patients of them showed ST segment elevation, 2 patients showed ST depression and 1 patient showed normal ECG findings. The diagnostic sensitivity of Tc-99m sestamibi myocardial perfusion SPECT was 100% by a qualified analysis. The perfusion defect site in the myocardial perfusion SPECT were corresponded with the infarct related coronary artery in 31 patients which was diagnosed by coronary angiograpy. The size of perfusion defect in the po1ar map was $31{\pm}18%(M{\pm}SD)$, in the myocardial infarction with left anterior descending coronary arery obstruction, $31{\pm}13% (M{\pm}SD)$ in the myocardial infarction with right coronary artery obstruction and $25{\pm}5.9%(M{\pm}SD)$ in the myocardial infarction with left circumflex coronary artery obstruction. We concluded that emergency myocardial perfusion SPECT images are useful in the diagnose of myocardial infarction and it's very useful when we are difficult to diagnose with ECG like as lateral wall infarction or left bundle branch block.

• The Korean Journal of Nuclear Medicine Technology
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• v.18 no.2
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• pp.28-32
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• 2014

Purpose Patient motion during myocardial perfusion SPECT can produce images that show visual artifacts and perfusion defects. This artifacts and defects remain a significant source of unsatisfactory myocardial perfusion SPECT. Motion correction has been developed as a way to correct and detect the patient motion for reducing artifacts and defects, and each motion correction uses different algorithm. We corrected simulated motion patterns with several motion correction methods and compared those images. Materials and Methods Phantom study was performed. The anthropomorphic torso phantom was made with equal counts from patient's body and simulated defect was added in myocardium phantom for to observe the change in defect. Vertical motion was intentionally generated by moving phantom downward in a returning pattern and in a non-returning pattern throughout the acquisition. In addition, Lateral motion was generated by moving phantom upward in a returning pattern and in a non-returning pattern. The simulated motion patterns were detected and corrected similarly to no-motion pattern image and QPS score, after Motion Detection and Correction Method (MDC), stasis, Hopkins method were applied. Results In phantom study, Changes of perfusion defect were shown in the anterior wall by the simulated phantom motions, and inferior wall's defect was found in some situations. The changes derived from motion were corrected by motion correction methods, but Hopkins and Stasis method showed visual artifact, and this visual artifact did not affect to perfusion score. Conclusion It was confirmed that motion correction method is possible to reduce the motion artifact and artifactual perfusion defect, through the apply on the phantom tests. Motion Detection and Correction Method (MDC) performed better than other method with polar map image and perfusion score result.

• Radiation Oncology Journal
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• v.25 no.1
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• pp.26-33
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• 2007

[ $\underline{Purpose}$ ]: The aim of this study is to evaluate and compare the incidence and aspects of myocardial perfusion defects in patients who were subjected to either two-dimensional or three-dimensional simulation techniques for early left-sided breast cancer. The myocardial perfusion defects were determined from using single photon emitted computerized tomography (SPECT) myocardial perfusion images. $\underline{Materials\;and\;Methods}$: Between January 2002 and August 2003, 32 patients were enrolled in this study. The patients were diagnosed as having early (AJCC stage T1-T2N0M0) left-sided breast cancer and were treated with tangential irradiation after breast-conserving surgery and systemic chemotherapy. The patients were divided into two groups according to the type of simulation received: two-dimensional simulation using an X-ray fluoroscope simulator or three-dimensional simulation with a CT simulator. All patients underwent technetium-99m-sestamibi gated perfusion SPECT at least 3 years after radiotherapy. The incidence and area of myocardial perfusion defects were evaluated and were compared in the two groups, and at the same time left ventricular ejection fraction and cardiac wall motion were also analyzed. The cardiac volume included in the radiation fields was calculated and evaluated to check for a correlation between the amount of irradiated cardiac volume and aspects of myocardial perfusion defects. $\underline{Results}$: A myocardial perfusion defect was detected in 11 of 32 patients (34.4%). There were 7 (46.7%) perfusion defect cases in 15 patients who underwent the two-dimensional simulation technique and 4 (23.5%) patients with perfusion defects in the three-dimensional simulation group (p=0.0312). In 10 of 11 patients who had myocardial perfusion changes, the perfusion defects were observed in the cardiac apex. The left ventricular ejection fraction was within the normal range and cardiac wall motion was normal in all patients. The irradiated cardiac volume of patients in the three-dimensional simulation group was less than that of patients who received the two-dimensional simulation technique, but there was no statistical significance as compared to the incidence of perfusion defects. $\underline{Conclusion}$: Radiotherapy with a CT simulator (three-dimensional simulation technique) for early left-sided breast cancer may reduce the size of the irradiated cardiac volume and the incidence of myocardial perfusion defects. Further investigation and a longer follow-up duration are needed to analyze the relationship between myocardial perfusion defects and clinical ischemic heart disease.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.3-9
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• 2009

Purpose: It is well-known that stress-induced stunning and reversible perfusion defect have impact on ejection fraction (EF) when performing myocardial perfusion SPECT. Due to these reasons, gated SPECT is recommended at stress and rest studies. And there was many experiments to analyze between Stress and Rest EF by using $^{99m}Tc$-MIBI. The aim of this study is to analyze between stress EF and rest EF at myocardial perfusion SPECT by using $^{201}Tl$ and define possible predictors of EF variability. Materials and Methods: From 2008 June to 2009 February, we analyzed 144 patients undergoing $^{201}Tl$ gated myocardial perfusion SPECT in ASAN medical center. To analyze the data, we use QGS (Quantitative gated SPECT) software, and derived End-systolic volume (ESV), End-diastolic volume (EDV), EF from the result. In this study, we comparatively analyzed stress/rest EF correlation based on stress/rest EF, EDV, ESV and reversibility of myocardial perfusion defect by using paired t-test, Bland-Altman analysis. Results: Mached pairs of stress EF and rest EF demonstrated excellent correlation (r=0.92) with no statistically significant difference (p=0.11). Bland-Altman analysis demonstrated a mean ${\Delta}EF$ was 0.52% (95% confidential interval[CI], -1.17~0.12%). No statistically significant difference between a mean ${\Delta}EF$ and hypothetic mean of 0 (${\Delta}EF$=0) (p=0.10). In the correlation of ${\Delta}EF$ according to stress/rest EDV and ESV, except rest ESV of <28mL (p<0.05), there was no statistically significant difference. In the correlation of ${\Delta}EF$ according to reversibility of perfusion defect, patients with reversible perfusion defect has statistically significant difference of ${\Delta}EF$ (p<0.05). ${\Delta}EF$ of stress/rest EF showed no statistically significant difference except 55% of rest EF (p<0.05). Conclusion: Like studies with $^{99m}Tc$-MIBI, there was generally no statistically significant difference between stress and rest EF in this study results. However a stress EF of <55%, a rest ESV of <28mL and patients with reversible perfusion defect showed statistically significant difference in ${\Delta}EF$. If performing $^{201}T$ myocardial perfusion SPECT to patients with abnormal cardiac function or reversible perfusion defect, consider this study results and apply it. We expect this study results could be useful predictors of ${\Delta}EF$ variability.

• The Korean Journal of Nuclear Medicine
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• v.38 no.3
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• pp.225-232
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• 2004

Purpose : Transient wall motion abnormality and contractile dysfunction of the left ventricle (LV) can be observed in patients with coronary artery disease due to post-stress myocardial stunning. To understand clinical characteristics of stress induced LV dysfunction, we have compared the findings of exercise stress test, myocardial perfusion SPECT and coronary angiography between subjects with and without post-stress LV dysfunction. Materials and Methods : Among subjects who underwent exercise stress test, myocardial perfusion SPECT and coronary angiography within a month of interval, we enrolled 36 patients with post-stress LV election fraction (LVEF) was $\geq5%$ lower than rest (stunning group) and 16 patients with difference of post-stress and rest LVEF was lesser than 1 %(non-stunning group) for this study. Treadmill exercise stress gated myocardial perfusion SPECT was performed with dual head SPECT camera using 740 MBq Tc-99m MIBI and coronary angiography was also performed by conventional Judkins method. Results : Stunning group had a significantly higher incidence of hypercholesterolemia than non-stunning group(45.5 vs. 7.1%, p=0.01). Stunning group also had higher incidence of diabetes mellitus and lower incidence of hypertension, but these were not statistically significant. Stunning group had larger and more severe perfusion defect in stress perfusion myocardial SPECT than non-stunning group(extent 18.2 vs. 9.2%, p=0.029; severity 13.5 vs. 6.9, p=0.040). Stunning group also had higher degree of reversibility of perfusion defect, higher incidence of positive exercise stress test and higher incidence of having severe stenosis ($80{\sim}99%$) in coronary angiography than non-stunning group, but these were not statistically significant. In stunning group, all of 4 patients without perfusion defect had significant coronary artery stenosis and had received revascularization treatment. Conclusion : Patients with post-stress LV dysfunction had larger and more severe perfusion defect and severe coronary artery stenosis than patients without post-stress LV dysfunction. All of the patients without perfusion defect in stunning group had significant coronary artery stenosis and needed revascularization. Therefore, we suggest that invasive diagnostic procedures and therapeutic interventions might be needed in patients with post-stress LV dysfunction.

• The Korean Journal of Nuclear Medicine
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• v.27 no.1
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• pp.51-58
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• 1993

We have anlayzed the polar maps of dipyridamole stress/rest $^{99m}Tc$-MIBI SPECT and compared the quantitated perfusion defects of dipyridamole stress polar map and the findings of coronary angiography in 56 pateints with coronary artery diseases. We performed the same day dipyridamole stress-rest myocardial SPECT, reconstructed the polar maps according to Cedars-Sinai method and quantitated perfusion detects of total myocardium and the territory of each artery, comparing the polar maps of patients with normal files. Stenosis more than 50 percent was considered significant and myocardial ischemic score was calculated as summed score of percents of main coronary arteries. Positive concordance of myocardial SPECT with coronary angiography were 82.6% with left anterior descending artery (LAD), 85.7% with left circumflex artery (LCx) and 78.6% with right coronary artery (RCA). Perfusion defect of SPECT polar map and the stenosis of coronary artery showed the contingency phi of 0.55 (p<0.0001) with total atreries, 0.38 (p = 0.016) with LAD, 0.50 (p<0.0001) with LCx and 0.40 (p = 0.007) with RCA. Dipyridamole stress percent defect of polar map was correlated with myocardial ischemic score with Spearman's rho of 0.47 (p = 0.001) in total arteries, 0.48 (p=0.001) in LAD, 0.56 (p < 0.001) in LCx and 0.38 (p=0.002) in RCA. These findings revealed that defect of the dipyridamole stress myocardial $^{99m}Tc$-MIBI SPECT and the percent extent of this defect were related with significant artery stenosis of individual arteries and the degree of stenosis. We thought that we could use the defects in the polar map of dipyridamole stress $^{99m}Tc$-MIBI SPECT for the quantification of myocardiasl perfusion decrease.