• Journal of Korean Neurosurgical Society
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• v.54 no.4
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• pp.280-288
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• 2013

Objective : Perfusion computed tomography (PCT) has the ability to measure quantitative value and produce maps of mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV). We assessed cerebral hemodynamics by using these parameters and acetazolamide (ACZ) challenge for pre- and post-procedural evaluation in patients with unilateral cerebrovascular stenotic disease. Methods : Thirty patients underwent pre-procedural PCT with ACZ challenge, and 24 patients (80%) was conducted follow up PCT after angioplasty with same protocol. The mean MTT, CBF, and CBV were measured and compared in both middle cerebral arterial (MCA) territories before and after ACZ challenge. Hemispheric ratio and percent change after ACZ challenge were calculated before and after angioplasty. Results : The mean stenosis rate was 76.6%. Significant increases in MTT (32.6%, p=0.000) and significant decreases in CBF (-14.2%, p=0.000) were found in stenotic side MCA territories. After ACZ challenge, there were significant changes in MTT (37.4%, p=0.000), CBF (-13.1%, p=0.000), and CBV (-10.5%, p=0.001) in pre-procedural perfusion study. However, no significant increases were found in MTT, or decreases in CBF and CBV in post-procedural study. There were no significant changes after ACZ challenge also. In addition, the degrees of these changes (before and after ACZ challenge) were highly correlated with the stenotic degrees in pre-procedural perfusion study. Conclusion : PCT with ACZ challenge appears to be a useful tool to assess the cerebral perfusion status especially in patients with unilateral symptomatic stenotic disease.

• The Korean Journal of Nuclear Medicine
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• v.26 no.2
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• pp.235-243
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• 1992

Patterns of abnormality in regional cerebral perfusion and its relation to clinical severity was evaluated with 32 head injury patients using $^{99m}Tc-HMPAO$ single photon emission tomography (SPECT). The findings were compared with computed tomography (CT) done within 48 hours of each SPECT study. The initial SPECT study was done within 7 days of injury in 16 cases, between 1 week and 2 months in 12, and after over 2 months in 4. Nineteen of the patients underwent followup SPECT and CT after a mean interval of 1 to 2 months. The initial SPECT showed abnormalities in 96% (31/32) of the patients while CT showed abnormal findings in only 81% (26/32). There were a total of 54 supratentorial SPECT lesions in all. Ninity percent (49/54) of these were of regional hypoperfusion, while 5 lesions showed focal hyperperfusion. The lesions were most often localized in the frontal and temporal lobes. Fifty five percent (30/54) were areas not detected as a lesion on CT. Cerebellar diaschisis was observed in 50% (16/32) of the patients. The degree of perfusion abnormality was quantified by the product of differential activity and a size factor. Correlation between the degree of perfusion abnormality and the clinical severity (Glasgow coma scale) failed to show statistical significance (p=0.053). The amount of change in the degree of perfusion abnormality on follow up SPECT was compared to the amount of change in clinical severity. Perfusion abnormality showed a tendancy to improve in most patients, and the degree of improvement showed significant correlation with the amount of clinical improvement (p < 0.01).

• Molecules and Cells
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• v.42 no.1
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• pp.45-55
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• 2019

The liver is involved in a wide range of activities in vertebrates and some other animals, including metabolism, protein synthesis, detoxification, and the immune system. Until now, various methods have been devised to study liver diseases; however, each method has its own limitations. In situ liver perfusion machinery, originally developed in rats, has been successfully adapted to mice, enabling the study of liver diseases. Here we describe the protocol, which is a simple but widely applicable method for investigating the liver diseases. The liver is perfused in situ by cannulation of the portal vein and suprahepatic inferior vena cava (IVC), with antegrade closed circuit circulation completed by clamping the infrahepatic IVC. In situ liver perfusion can be utilized to evaluate immune cell migration and function, hemodynamics and related cellular reactions in each type of hepatic cells, and the metabolism of toxic or other compounds by changing the composition of the circulating media. In situ liver perfusion method maintains liver function and cell viability for up to 2 h. This study also describes an optional protocol using density-gradient centrifugation for the separation of different types of hepatic cells, allowing the determination of changes in each cell type. In summary, this method of in situ liver perfusion will be useful for studying liver diseases as a complement to other established methods.

• Journal of Chest Surgery
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• v.54 no.6
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• pp.487-493
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• 2021

Background: Predicting postoperative lung function after pneumonectomy is essential. We retrospectively compared postoperative lung function to predicted postoperative lung function based on computed tomography (CT) volumetry and perfusion scintigraphy in patients who underwent pneumonectomy. Methods: Predicted postoperative lung function was calculated based on perfusion scintigraphy and CT volumetry. The predicted function was compared to the postoperative lung function in terms of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV₁), using 4 parameters: FVC, FVC%, FEV₁, and FEV₁%. Results: The correlations between postoperative function and predicted function based on CT volumetry were r=0.632 (p=0.003) for FVC% and r=0.728 (p<0.001) for FEV₁%. The correlations between postoperative function and predicted postoperative function based on perfusion scintigraphy were r=0.654 (p=0.002) for FVC% and r=0.758 (p<0.001) for FEV₁%. The preoperative Eastern Cooperative Oncology Group (ECOG) scores were significantly higher in the group in which the gap between postoperative FEV₁ and predicted postoperative FEV₁ analyzed by CT was smaller than the gap analyzed by perfusion scintigraphy (1.2±0.62 vs. 0.4±0.52, p=0.006). Conclusion: This study affirms that CT volumetry can replace perfusion scintigraphy for preoperative evaluation of patients needing pneumonectomy. In particular, it was found to be a better predictor of postoperative lung function for poor-performance patients (i.e., those with high ECOG scores).

• 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.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.13-22
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• 2005

It has been known that pulsatile flow is physiologic and more favorable to tissue perfusion than nonpulsatile flow. The purpose of this study is to directly compare the effect of pulsatile versus nonpulsatile blood flow to renal tissue perfusion in extracorporeal circulation by using a tissue perfusion measurement system. Material and Method: Total cardiopulmonary bypass circuit was constructed to twelve Yorkshire swines, weighing 20$\~ $30 kg. Animals were randomly assigned to group 1 (n=6, non pulsatile centrifugal pump) or group 2 (n=6, pulsatile T-PLS pump). A probe of the tissue perfusion measurement system $(QFlow^{TM}-500)$ was inserted into the renal pa­renchymal tissue. Extracorporeal circulation was maintained for an hour at a pump flow of 2 L/min after aortic cross-clamping. Tissue perfusion flow of the kidney was measured at baseline (before bypass) and every 10 minutes after bypass. Serologic parameters were collected at baseline and 60 minutes after bypass. Result: Baseline parameters were not different between the groups. Renal tissue perfusion flow was substantially higher in the pulsatile group throughout the bypass (ranged 48.5$\~$ 64 in group 1 vs. 65.8$\~$88.3 mL/min/100 g in group 2, p=0.026$\~$ 0.45) The difference was significant at 30 minutes bypass $(47.5{\pm}18.3\;in\;group\;1\;vs.\;83.4{\pm}28.5$ mL/min/100 g in group 2, p=0.026). Serologic parameters including plasma free hemoglobin, blood urea nitrogen, and creatinine showed no differences between the groups at 60 minutes after bypass (p=NS). Conclusion: Pulsatile flow is more beneficial to tissue perfusion of the kidney in short-term extracorporeal circulation. Further study is suggested to observe the effects to other vital organs or long-term significance.

• 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.

• Journal of the Korean Society of Radiology
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• v.12 no.1
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• pp.47-52
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• 2018

Brain perfusion CT scanning is often employed usefully in clinical conditions as it accurately and promptly provides information about the perfusion state of patients having acute ischemic stroke with a lot of time constraints and allows them to receive proper treatment. Despite those strengths of it, it also has a serious weakness that Lens may be exposed to a lot of dose of radiation in it. In this study, as a way to reduce the dose of radiation to Lens in brain perfusion CT scanning, this researcher conducted an experiment with Bismuth shielding and change of patients' position. TLD (TLD-100) was placed on both lens using the phantom (PBU-50), and then, in total 4 positions, parallel to IOML, parallel to IOML (Bismuth shielding), parallel to SOML, and parallel to SOML (Bismuth shielding), brain perfusion scanning was done 5 times for each position, and dose to Lens were measured. Also, to examine how the picture quality changed in different positions, 4 areas of interest were designated in 4 spots, and then, CT number and noise changes were measured and compared. According to the results of conducting one-way ANOVA on the doses measured, as the significance probability was found to be 0.000, so there was difference found in the doses of radiation to crystalline lenses. According to the results of Duncan's post-hoc test, with the scanning of being parallel to IOML as the reference, the reduction of 89.16% and 89.66% was observed in the scanning of being parallel to SOML and that of being parallel to SOML (Bismuth shielding) respectively, so the doses to Lens reduced significantly. Next, in the scanning of being parallel to IOML (Bismuth shielding), the reduction of 37.12% was found. According to the results, reduction in the doses of radiation was found the most significantly both in the scanning of being parallel to SOML and that of being parallel to SOML (Bismuth shielding). With the limit of the equivalent dose to Lens as the reference, this researcher conducted comparison with the dose to occupational exposure and dose to Public exposure in the scanning of being parallel to IOML and found 39.47% and 394.73% respectively; however in the scanning of being parallel to SOML (Bismuth shielding), considerable reduction was found as 4.08% and 40.8% respectively. According to the results of evaluation on picture quality, every image was found to meet the evaluative standards of phantom scanning in terms of the measurement of CT numbers and noise. In conclusion, it would be the most useful way to reduce the dose of radiation to Lens to use shields in brain perfusion CT scanning and adjust patients' position so that their lens will not be in the field of radiation.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.51-57
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• 2011

Purpose: The aim of this study is to identify clinical usefulness of Wide Beam Reconstruction (WBR) which is called Xpress.cardiac$^{TM}$ to confirm the agreement between segmental perfusion and regional wall motion in myocardium compared to conventional OSEM method. Materials and Methods: Subjects were separated two groups. First group was composed of 20 normal control group. Second group was composed of 10 patients (abnormal group) who had coronary artery disease. Subjects underwent myocardial perfusion SPECT ($^{201}Tl$ rest and $^{99m}Tc$-MIBI stress). Image acquisition and reconstruction were that rest stage was each step per 30, 15 seconds and stress stage was each step per 25, 13 seconds, OSEM and WBR methods were applied. Segmental perfusion and regional wall motion were applied 20-segment model of QPS, QGS algorithm in AutoQuant. Status of perfusion was composed of 5 point scoring system (0=normal, 1=mild, 2=moderate, 3=severe hypokinesia, 4=dyskinesia). Status of regional wall motion was also composed of 5 point scoring (0=normal, 1=mild, 2=moderate, 3=severe hypokinesia, 4=dyskinesia). We evaluated the agreement between conventional OSEM and WBR through automatic quantification value. Results: The agreement of rest segmental perfusion between conventional OSEM and WBR in normal patients was 99% (396/400, k=0.662, p<0.0001) and one of rest regional wall motion was 83.8% (335/400, k=0.283), the agreement of stress segmental perfusion was 95.8%(383/400, k=0.656), one of stress regional wall motion was 87.3% (349/400, k=0.390). The match rate of rest segmental perfusion in abnormal patients was 83% (166/200, k=0.605, p<0.0001) and one of rest regional wall motion was 55.5% (111/200, k=0.385), the agreement of stress segmental perfusion was 79.5% (159/200, k=0.682), one of stress regional wall motion was 63.5% (127/200, k=0.486). Conclusion: Compared to conventional OSEM, WBR method had a good agreement of segmental perfusion in myocardium in normal and abnormal groups. However regional wall motion showed meaningful low agreement. Although WBR offers high resolution and contrast ratio, it is not useful method for gated myocardial perfusion SPECT.

• 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.