• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.711-714
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• 1998

H$_2$$^{15}$ O PET을 이용하여 심근혈류를 측정할 때 물의 분포가 조직마다 불균일한 특성을 나타내고자 관류 가능한 조직분획(perfusable tissue index; PTI)$^{1)}$ 개념을 도입한 연구가 보고된 바 있으나 PTI로는 비균일성을 정량적으로 다루지 못하였다$^{2)}$ . 반면에 단일 구획 모델에서 분배계수(partition coefficient: λ)를 변수로 추정하여 혈류분포의 비 균일성을 나타낼 수 있음을 컴퓨터 모의실험으로 보인 연구가 있다$^{3)}$ . 이 연구에서는 이미 앞서 발표한 연구의 혈류측정 모델을 정상인 실험용 개에 적용하였으며 그 결과 혈류와 분배계수 모두가 정상 범위 안에 들어옴을 확인하였다. 또한 컴퓨터 모의실험을 통해 얻은 분배계수와 비균일성 지표인 구성비균일성(constitution heterogeneity; CH) 와의 관계를 이용하여 동물실험에서 측정한 분배계수로부터 CH를 유추해 보았다.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.31 no.3 s.52
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• pp.259-263
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• 2005

The aim of the present study is to evaluate relationship between UV-induced MED and perfusion value assessed by Laser Doppler Perfusion Imager. In this study, A increasing linear relationship is seen between perfusion and dose (p<0.05). The dose-response curve show a steep slope in the case of lower MED values group after MED point, For higher MED group, increase with a gentle slope.

• Journal of Chest Surgery
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• v.34 no.2
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• pp.111-117
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• 2001

배경: 심근 수축력과 더불어 전신저항은 개심술 후 적절한 심박출량을 유지하기 위한 매우 중요한 요인이다. 후부하의 변화를 비관혈적으로 평가할 수 있는지 알아 보고자 대동맥 혈류파형의 변화를 관찰하였다. 대상 및 방법: 개흉한 8마리의 잡견에서 연속파형 Doppler 심초음파를 이용하여 nitroprusside 단독 또는 epinephrine과의 병합투여 잔후로 상행 대동맥 혈류를 측정하였다. 결과: Nitroprusside의 투여로 동맥압과 전신저항은 약물의 투여량에 비례하여 감소함으로써(p<0.05 vs 기준치), 대동맥 혈류파형의 최고속도, 평균가속 및 분거리(속도시간적분$\times$심박동수)는 증가하였고, 가속시간은 짧아졌으며(p<0.05 vs 기준치), 가속시간/박출시간의 비는 변화가 없었다. Nitroprusside 투여로 인한 전신저항의 변화는 속도시간적분이나 Doppler 시간간격 지표보다는 최고속도(r=0.60, p=0.001)와 평균가속(r=0.52, p=0.003)과 상관관계가 있었다. Epinephrine과의 병합투여로 전신저항이 증가하지 않는 한 nitroprusside 단독투여에 비해서 최고속도, 평균가속 및 속도시간적분이 더 크게 증가했으나, 전신저항이 증가되면 이 Doppler 지표들은 감소하는 경향을 보였다. 결론: Doppler 심초음파를 이용하여 상행 대동맥 혈류파형의 최고속도와 평균가속을 연속적으로 측정함으로써 후부하의 변화를 비관혈적으로 평가할 수 있으리라 생각된다.

• Journal of the Korean Society of Clothing and Textiles
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• v.25 no.10
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• pp.1745-1753
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• 2001

본 연구는 한랭 환경 하에서의 인체의 국소 가온 자극이 생리, 감각반응에 끼치는 영향을 검토했다. 건강한 성인여자 7명을 대상으로, 기온 $25^{\circ}C$, 습도50%의 환경 하에서 균일한 국소 가온을 부하 했을 때 피부온, 고막온, 손가락, 발가락 혈류량, 온냉감, 쾌적감의 반응에 미치는 영향을 검토한 결과는 다음과 같다. 1) 국소가온에 의해 가온 부위 피부온은 유의하게 상승하고 가온 부위에 따라 상승도에는 유의한 차가 보였다. 2) 국소가온에 의해 고막온은 머리의 가온 시에 높은 상승, 전완의 가온 시에 상승하고, 다른 가온 부위에서는 하강의 경향이 보였다. 3) 국소가온에 의해 혈류량의 변화는 3개의 군으로 분류된다. 가온과 함께 손가락 혈류량이 증가하는 군, 발가락 혈류량이 변화하는 군, 양쪽의 혈류량이 적게 변화하는 군으로 나누어진다. 이것을 각 피험자의 평균 피부온 수준 즉 체온조절 수준과 관계 있는 것으로 논할 수 있다 4)국소 가온에 의해 각 부 위 피부온으로의 파급효과는 머리, 상완의 가온 시에 크지만 대퇴, 하퇴 다리의 가온 시에는 대부분의 부위에서 영향이 보이지는 않았다. 5) 이와 같이 국소 가온에 의 한 생리, 감각반응은 가온 부위에 따라 다르고 머리, 상완의 가온 시에는 생리반응이 크고 하퇴, 다리의 가온시에는 국소의 감각변화가 컸다.

• The Korean Journal of Nuclear Medicine
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• v.34 no.6
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• pp.445-455
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• 2000

Purpose: We evaluated the distribution of hypoperfusion in patients with traumatic brain injury (TBI) and the relationship of thalamic hypoperfusion to severity of cognitive and behavioral sequelae. Materials and Methods: Tc-99m ECD SPECT and MRI were performed in 103 patients (M/F=81/22, mean age $34.7{\pm}15.4$ yrs) from 0.5 to 55 months (mean 10.3 months) after TBI. The patients were divided into three groups showing no abnormalities (G1), focal (G2) and diffuse injury (G3) on MRI. Psychometric tests assessed 11 cognitive or behavioral items. In all patients, we evaluated the distribution of hypoperfused areas in SPECT, and in 57/103 patients, neuropsychological (NP) abnormalities in patients with thalamic hypoperfusion were compared with those of patients without thalamic hypoperfusion. Results: The perfusion deficits were most frequently located in the frontal lobe (G1, 42.3%: G2 34.5%: G3 33.3%), temporal lobe ($24{\sim}26%$) thalami ($21{\sim}22.4%$), parietal and occipital lobe (${\leq}10%$). Numbers of NP abnormalities in the cases of cortical hypoperfusion with or without concomitant thalamic hypoperfusion were following: the former $4.7{\pm}1.5$ and the latter $3.2{\pm}1.4\;in\;G1,\;5.0{\pm}1.1\;and\;4.8{\pm}1.2\;in\;G2,\;6.8{\pm}1.8\;and\;6.3{\pm}1.1\;in\;G3$, respectively. This difference according to thalamic hypoperfusion was significant in G1 (p=0.002), but was not significant in G2 or G3. Conclusion: SPECT in patients with TBI had demonstrated hypoperfusion mostly involving the frontal, temporal and thalami. In normal group on MRI, frontal hypoperfusion was more prominent than that of any other group, Furthermore in this group, SPECT could predict severity of NP outcome by concomitant thalamic hypoperfusion with cerebral cortical abnormalities.

• Journal of the Korean Magnetics Society
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• v.26 no.4
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• pp.142-148
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• 2016

To evaluate the effect of flip angle on flow rate measurements obtained with phase contrast MRI according to the flip angle degree in ascending aorta and velocity encoding (VENC) was (150 m/s). 1.5T MRI in patients 17 (female: 8, male: 9, mean age $57.9{\pm}15.4$) as a target by applying a non-breath holding techniques to flip angle VENC (150 cm/s) in each of the ascending aorta was measured by changing $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$. Blood was obtained a peak velocity, average velocity, net forward volume, net forward volume/body surface area. Ascending aorta from average velocity (AV) measured the average value of the flip angle $20^{\circ}$ (9.87 cm/s), $30^{\circ}$ (9.6 cm/s) and $40^{\circ}$ (10.05 cm/s). Blood flow VENC in was blood flow change in flip angle change was high most blood flow measurement when the flip angle $30^{\circ}$ in VENC, crouching each blood flow is also proportional to the increases in the $20^{\circ}$ to $40^{\circ}$ and was increased, the deviation of the peak velocity and the average velocity is the smallest deviation from the flip angle $30^{\circ}$. Flip angle $20^{\circ}$, $30^{\circ}$ and $40^{\circ}$ in peak velocity, average velocity, net forward volume, net forward volume/body surface area was no statistically significant difference (p > .05). Blood flow velocity and blood flow is measured by applying to adjust the flip angle accurately calculate the blood flow is important information for diagnosis and treatment of cardiovascular diseases, and can help in the examination on the blood flow measurement.

• The Korean Journal of Nuclear Medicine
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• v.28 no.1
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• pp.17-21
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• 1994

We studied 115 patients with seizure who had been performed brain SPECT, brain MRI or CT and EEG. To evaluate the pattern of brain SPECT in seizure patients 28 of them had secondary epilepsies, 87 had primary epilepsies. In primary epilepsies, 42 were generalized seizure and 45 were partial seizure. The causes of secondary epilepsies were congenital malformation, cerebromalacia, cerebral infarction, multiple sclerosis, AV-malformation, granuloma and etc, in order. In 28 secondary epilepsies, 25 of them, brain SPECT lesions was concordant with MRI or CT lesions, 3 were disconcordant. The brain SPECT findings of generalized seizure were normal in 22 patients, diffuse irregular decreased perfusion in 8, decreased in frontal cortex in 4, temporal in 5 and frontotemporal in 3. In 45 partial seizure, 19 brain SPECT were concordant with EEG (42.4%).

• Journal of Oral Medicine and Pain
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• v.34 no.1
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• pp.115-122
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• 2009

The following results were obtained, after experimenting on change of masseter muscle and bloodstream epithelium with Transcutaneous Electrical Nerve Stimulator(TENS), among 16 male adults. 1. According to applying TENS, it was observed that bloodstream in muscle increases at 1.5, 3.0 Hz. 2. According to applying TENS, it was observed that concentration of moving blood cells in muscle increase at 1.5, 3.0, 6.0 Hz. 3. According to applying TENS, it was observed that velocity of bloodstream in muscle increases only at 1.5 Hz 4. Through experiment, applying TENS at level of 6.0 and 10.0 Hz, all bloodstream, concentration of moving blood cells, and velocity of bloodstream increasing rates were lower in muscle compared to of them in overlying epithelium; and especially increasing bloodstream and its velocity were most frequent at 6.0 Hz, and bloodstream of 10.0 Hz. From the results above when a physical therapy of TENS is carried out the frequency of 1.5, 3.0 H is effective, and as the frequency increases it is disadvantageous to the muscle.

• Restorative Dentistry and Endodontics
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• v.30 no.6
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• pp.470-476
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• 2005

The purpose of this Study was to invest)gate the function or calcitonin gene-related peptide (CGRP) in regulatory mechanism of pulpal microcirculation with the aim of elucidating neurogenic inflammation. Experiments were performed on twelve cats under general anesthesia. CGRP was administered through the femoral vein to see the systemic Influence and through the external carotid artery to see the local effect. Sympathetic nerve to the dental pulp was stimulated electrically and pulpal blood flow (PBF) was measured with a laser Doppler flowmeter on the canine teeth to the drug administration. The paired variables of control and experimental data were compared by paired t-test and differences with p < 0.05 were considered statistically significant. Systemic administration of CGRP $(0.3{\mu}g/ka)$ exerted decreases in systemic blood pressure and caused changes in PBF with an initial increase i311owed by decrease and a move marked second increase and decrease. Close intra-arterial (i.a.) injection of CCRP $(0.03{\mu}g/kg)$ resulted in slight PBF increase. The effect of CGRP resulted in no significant increase in PBF in the presence of $CGRP_{8-37}$. The electrical stimulation of the sympathetic nerve alone resulted in PBF decreases. The j.a. administration of CGRP following the electrical stimulation of the sympathetic nerve compensated the decreased PBF. Therefore, CGRP effectively blocked the sympathetic nerve stimulation-induced PBF decrease. Results of the present study have provided evidences that even though the local vasodilatory function of CGRP are weak, CCRP is effectively involved in blocking the vasoconstriction caused by sympathetic nerve stimulation in the feline dental pulp.

• Investigative Magnetic Resonance Imaging
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• v.10 no.2
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• pp.70-80
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• 2006

Spin echo gradient moment nulling pulse sequences were designed and implemented on a clinical magnetic resonance imaging system. A new technique was introduced for flow compensation that minimized echo time and effectively suppresses unwanted echoes on the slice selection gradient axis in spin echo sequences. A unified gradient shape was used in all orders of flow compensation up to the third order. A dual-purpose gradient was applied for flow compensation and to reduce unwanted artifacts. The sequences were used to generate images of phantoms and/or human brains. This technique was especially good at reducing eddy currents and artifacts related to imperfection of the refocusing pulse. The developed sequences were found to have shorter echo times and better flow compensation in through-plane flow than those of the previous models that were used by other investigators.