• Journal of Yeungnam Medical Science
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• 제4권1호
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• pp.1-15
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• 1987

Magnetic Resonance (M.R.) is rapidly emerging technique that provides high quality images and potentially provides much more diagnostic information than do conventional imaging modalities. M.R.I. is conceptually quite different from currently used imaging methods. The complex nature of M.R.I. allows a great deal of flexibility in image product ion and available information, and key points are as follows. 1. M.R.I. offers a non-invasive technique with which to gene rate in vivo human images without ionizing radiation and with no known adverse biological effects. 2. Imaging mechanism of M.R.I. is quite different from conventional imaging modality and for more accurate diagnostic application, It is necessary for physician to understand imaging mechanism of M.R.I. 3. M.R. makes available basic chemical parameters that may provide to be useful for diagnostic medical imaging and more specific pathophysiologic information which are not available by alternate techniques. 4. M.R. can be produced by number of different methods. This flexibility allows the imaging technique to be applicated for particular clinical purpose. Multiplanar and three dimensional imaging may extend the imaging process beyond the single section available with current CT. 5. Future directions include efforts to; a. Further development of hard ware b. More fasternning scan time c. Respiratory and cardiac gated imaging d. Imaging of additional nuclei except hydrogen e. Further development of contrast media f. M.R. in vivo spectroscopy g. Real time M.R. imaging.

• Investigative Magnetic Resonance Imaging
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• 제21권1호
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• pp.20-27
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• 2017

Purpose: To evaluate quantification results of single breath-hold (SBH) magnetic resonance (MR) cine imaging compared to results of conventional multiple breath-hold (MBH) technique for left ventricular (LV) function in patients with cardiac arrhythmia. Materials and Methods: MR images of patients with arrhythmia who underwent MBH and SBH cine imaging at the same time on a 1.5T MR scanner were retrospectively reviewed. Both SBH and MBH cine imaging were performed with balanced steady state free precession. SBH scans were acquired using temporal parallel acquisition technique (TPAT). Fifty patients ($65.4{\pm}12.3years$, 72% men) were included. End-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV), ejection fraction (EF), myocardial mass, and LV regional wall motion were evaluated. Results: EF, myocardial mass, and regional wall motion were not significantly different between SBH and MBH acquisition techniques (all P-values > 0.05). EDV, ESV, and SV were significant difference between the two techniques. These parameters for SBH cine imaging with TPAT tended to lower than those in MBH. EF and myocardial mass of SBH cine imaging with TPAT showed good correlation with values of MBH cine imaging in Passing-Bablok regression charts and Bland-Altman plots. However, SBH imaging required significantly shorter acquisition time than MBH cine imaging ($15{\pm}7sec$ vs. $293{\pm}104sec$, P < 0.001). Conclusion: SBH cine imaging with TPAT permits shorter acquisition time with assessment results of global and regional LV function comparable to those with MBH cine imaging in patients with arrhythmia.

• Nuclear Medicine and Molecular Imaging
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• 제43권3호
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• pp.159-164
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• 2009

Coronary artery disease is on the rise over the world. Myocardial perfusion SPECT is a well established technique to detect coronary artery disease and to assess left ventricular function. In addition, it has the unique ability to predict the prognosis of the patients. Moreover, the application of ECC-gated images provided the quantitatve data and improved the accuracy. This approach has been proved to be cost-effective and suitable for the emerging economies as well as developed countries. However, the utilization of nuclear cardiology procedures vary widely considering the different countries and region of the world. Korea exits 2-3 times less utilization than Japan, and 20 times than the United States. Recently, with the emerging of new technology, namely cardiac CT, cardiac MR and stress echocardiography, the clinical usefulness of nuclear cardiology has been called in question and its role has been redefined. For the proper promotion of nuclear cardiology, special educations should be conducted since the nuclear cardiology has the contact points between nuclear medicine and cardiology. Several innovations are in horizon which will impact the diagnostic accuracy as well as imaging time and cost savings. Development of new tracers, gamma camera technology and hybrid systems will open the new avenue in cardiac imaging. The future of nuclear cardiology based on molecular imaging is very exciting. The newly defined biologic targets involving atherosclerosis and vascular vulnerability will allow the answers for the key clinical questions. Hybrid techniques including SPECT/CT indicate the direction in which clinical nuclear cardiology may be headed in the immediate future. To what extent nuclear cardiology will be passively absorbed by other modalities, or will actively incorporate other modalities, is up to the present and next generation of nuclear cardiologists.

• 대한핵의학회지
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• 제37권4호
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• pp.207-218
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• 2003

Myocardial perfusion imaging has been increasingly used to provide prognostic data and guidance on the choice of appropriate management of patients with known or suspected coronary artery disease. The electrocardiogram gated myocardial SPECT program is corning into wide use with an advent of $^{99m}Tc-labeled$ tracers and an improvement of SPECT machines. The gated technique permits measurement of important cardiac prognostic indicators without any further discomforts or radiation burden in patients underwent standard myocardial perfusion SPECT. In addition, gated study significantly improves diagnostic yield by reducing the number of borderline interpretations and could find myocardial stunning and viable myocardium. Gated single photon emission computed tomography (SPECT) imaging allows the automated calculation of end-diastolic volume, end-systolic volume, ejection fraction, myocardial mass and the assessment of regional wall motion and thickening, and it have dramatically improved assessment of coronary artery disease in routine nuclear practice. This allows the simultaneous assessment of both perfusion and function within the same acquisition, and serves as a cost-effective technique for providing more diagnostic data with fewer diagnostic tests. Because the diagnostic and prognostic power derived from knowledge of left ventricular function can be added to that provided by assessing myocardial perfusion, gated SPECT imaging has rapidly gained widespread acceptance and is now used on a routine clinical basis in a growing number of laboratories, including South Korea. The gated SPECT technique for measurement of left ventricular parameters has been validated against a variety of well established techniques. In this work, overview of gated myocardial perfusion SPECT focus on functional parameters is presented.

• 핵의학기술
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• 제12권3호
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• pp.192-198
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• 2008

Purpose: The scan time reduction helps to yield more accurate results and induce the minimization of patient's motion. Also we can expect that satisfaction of examination will increase. Nowdays medical equipment companies have developed various programs to reduce scan time. We used Onco. Flash (Pixon method, SIEMENS) that is an image processing technique gated cardiac blood pool scan and going to evaluate its clinical usefullness. Materials and Method: We analyzed the 50 patients who were examined by gated blood pool scan in nuclear medicine department of Asan Mediacal Center from June $20^{th}$ 2008 to August $14^{th}$ 2008. We acquired the Full-time (6000 Kcounts) and Half-time (3000 Kcounts) LAO image in same position. And we acquired LVEF values ten times from Full-time, Half-time images acquired by the image processing technique and analyzed its mean and standard deviation values. To estimate LVEF in same conditions, we set automatic location of the LV ROI and background ROI based on same X and Y-axis. Also we performed blinding tests to physician. Results: After making a quantitative analysis of the 50 patients EF values, each mean${\pm}$standard deviation is shown at Full-time image $68.12{\pm}7.84%$, Half- time (acquired by imaging processing technique) $68.49{\pm}8.73%$. In the 95% confidence limit, there was no statistically significant difference (p>0.05). After blinding test with a physician for making a qualitative analysis, there was no difference between Full-time image and Half-time image acquired by the image processing technique for observing LV myocardial wall motion. Conclusion: Gated cardiac blood pool scan has been reported its relatively exact EF measured results than ultrasound or CT. But gated cardiac blood pool scan takes relatively longer time than other exams and now it needs to improve time competitive power. If we adapt Half-time technique to gated cardiac blood pool scintigraphy based on this study, we expect to reduce possible artifacts and improve accessibility as well as flexibility to exam. Also we expect patient's satisfaction.

• 대한영상의학회지
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• 제81권2호
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• pp.302-309
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• 2020

파브리병(Fabry disease)은 매우 드문 X-연관 유전 대사 질환으로 알파 갈락토시다아제(alpha galactosidase A)의 결핍으로 인하여 다양한 세포 및 기관에 글리코스핑고지질(glycosphingolipid)의 축적을 초래하는 질환이다. 심장 침범이 비교적 흔하며 비정상적인 지질침착으로 인한 심근 염증, 좌심실 비대 및 심근 섬유증을 일으킨다. 심장 침범은 환자 예후를 결정하는 중요한 요인이므로 이를 진단하는 것은 매우 중요하다. 심장 자기공명영상은 심실의 기능, 부피 측정을 위한 표준기법으로 알려져 있으며 심근의 조직 변화를 볼 수 있는 유용한 기법이다. 특히 최근 많이 쓰이는 T1 지도화 기법을 통한 심근 조영 전 T1 수치를 이용하여 파브리병의 심장 침범을 조기 진단할 수 있으며 자기공명영상을 이용한 심근 질량 측정으로 치료 모니터링을 할 수 있다. 심장 자기공명영상은 파브리병 환자에서 다양한 역할을 할 수 있을 것으로 생각되며 이에 대해 정리해보고자 한다.

• The Korean Journal of Physiology and Pharmacology
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• 제28권4호
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• pp.335-344
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• 2024

Diphenyleneiodonium (DPI) has been widely used as an inhibitor of NADPH oxidase (Nox) to discover its function in cardiac myocytes under various stimuli. However, the effects of DPI itself on Ca²⁺ signaling and contraction in cardiac myocytes under control conditions have not been understood. We investigated the effects of DPI on contraction and Ca²⁺ signaling and their underlying mechanisms using video edge detection, confocal imaging, and whole-cell patch clamp technique in isolated rat cardiac myocytes. Application of DPI suppressed cell shortenings in a concentration-dependent manner (IC₅₀ of ≅0.17 µM) with a maximal inhibition of ~70% at ~100 µM. DPI decreased the magnitude of Ca²⁺ transient and sarcoplasmic reticulum Ca²⁺ content by 20%-30% at 3 µM that is usually used to remove the Nox activity, with no effect on fractional release. There was no significant change in the half-decay time of Ca²⁺ transients by DPI. The L-type Ca²⁺ current (I_Ca) was decreased concentration-dependently by DPI (IC₅₀ of ≅40.3 µM) with ≅13.1%-inhibition at 3 µM. The frequency of Ca²⁺ sparks was reduced by 3 µM DPI (by ~25%), which was resistant to a brief removal of external Ca²⁺ and Na⁺. Mitochondrial superoxide level was reduced by DPI at 3-100 µM. Our data suggest that DPI may suppress L-type Ca²⁺ channel and RyR, thereby attenuating Ca²⁺-induced Ca²⁺ release and contractility in cardiac myocytes, and that such DPI effects may be related to mitochondrial metabolic suppression.

• 대한임상검사과학회지
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• 제38권2호
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• pp.135-140
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• 2006

Magnetocardiography (MCG) is the measurement and analysis of the magnetic component of the electro-magnetic field of the human heart, usually conducted externally, using extremely sensitive devices such as a Superconducting Quantum Interference Device (SQUID). MCG is a totally noninvasive method, it uses neither radiation nor ultrasonics. The magnetic activity of the heart is registered from outside the thorax. MCG has a very high sensitivity and a high spatial resolution for very a small, local myocardial current. In comparison to the electrical signals measured by an ECG, the magnetic signal does not disturb the boundaries of tissues with different electrical properties. MCG measures the myocardial function rather than describing the morphology. MCG is a relatively new technique that promises good spatial resolution and extremely high temporal resolution, thus complementing other heart activity measurement techniques such as Electrocardiography (ECG). The clinical uses of MCG are in detecting various cardiac disorders including myocardial infarction, ventricular hypertrophy, ventricular conduction defects, Wolff-Parkinson-White (WPW) syndrome, sudden cardiac death and fetal magnetocardiography. Magnetocardiography may be used alone or together with electrcardiography for the measurement of spontaneous or overloaded activity and for research or clinical purposes.

• Journal of Cardiovascular Imaging
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• 제31권2호
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• pp.71-82
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• 2023

BACKGROUND: Cardiac magnetic resonance fingerprinting (cMRF) enables simultaneous mapping of myocardial T1 and T2 with very short acquisition times. Breathing maneuvers have been utilized as a vasoactive stress test to dynamically characterize myocardial tissue in vivo. We tested the feasibility of sequential, rapid cMRF acquisitions during breathing maneuvers to quantify myocardial T1 and T2 changes. METHODS: We measured T1 and T2 values using conventional T1 and T2-mapping techniques (modified look locker inversion [MOLLI] and T2-prepared balanced-steady state free precession), and a 15 heartbeat (15-hb) and rapid 5-hb cMRF sequence in a phantom and in 9 healthy volunteers. The cMRF_5-hb sequence was also used to dynamically assess T1 and T2 changes over the course of a vasoactive combined breathing maneuver. RESULTS: In healthy volunteers, the mean myocardial T1 of the different mapping methodologies were: MOLLI 1,224 ± 81 ms, cMRF_15-hb 1,359 ± 97 ms, and cMRF_5-hb 1,357 ± 76 ms. The mean myocardial T2 measured with the conventional mapping technique was 41.7 ± 6.7 ms, while for cMRF_15-hb 29.6 ± 5.8 ms and cMRF_5-hb 30.5 ± 5.8 ms. T2 was reduced with vasoconstriction (post-hyperventilation compared to a baseline resting state) (30.15 ± 1.53 ms vs. 27.99 ± 2.07 ms, p = 0.02), while T1 did not change with hyperventilation. During the vasodilatory breath-hold, no significant change of myocardial T1 and T2 was observed. CONCLUSIONS: cMRF_5-hb enables simultaneous mapping of myocardial T1 and T2, and may be used to track dynamic changes of myocardial T1 and T2 during vasoactive combined breathing maneuvers.

• 핵의학기술
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• 제12권1호
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• pp.33-38
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• 2008

Purpose: The Gated cardiac blood pool scan is non-invasive method that a quantitative evaluation of left ventricular function. Also this scan have shown the value of radionuclide ejection fraction measurements during the course of chemotherapy as a predictor of cardiac toxicity. Therefore a reliable method of monitoring its cardiotoxic effects is necessary. the purpose of this study is to minimize the overestimate of left ventricular ejection fraction (LVEF) by modified body position to reduce the influence of scattered rays from surrounding organs of the heart in the background region of interest. Materials and Methods: Gated cardiac blood pool scan using in vivo $^{99m}Tc$-red blood cell (RBC) was carried out in 20 patients (mean $44.8{\pm}8.6$ yr) with chemotherapy for a breast carcinoma. Data acquisition requires about 600 seconds and 24 frames of one heart cycle by the multigated acquisition mode, Synchronization deteriorates toward the end of the cycle and with the distance from the trigger signal (R-wave) by ECG gating. Gated cardiac blood pool scan was studied with conventional method (supine position and the detector head in $30-45^{\circ}$ left anterior oblique position and caudal $10-20^{\circ}$ tilt) and compared with modified method (left lateral flexion position with 360 mL of drinking water). LVEF analysis was performed by using the automatically computer mode. Results: The ROI counts of modified scan method were lower than LV conventional method ($1429{\pm}251$ versus $1853{\pm}243$, <0.01). And LVEF of modified method was also decrease compared with conventional method ($58.3{\pm}5.6%$ versus $65.3{\pm}6.1%$, <0.01). Imaging analysis indicated that stomach was expanded because of water and spleen position was changed to lateral inferior compared with conventional method. Conclusion: This study shows that the modified method in MUGA reduce the influence of scattered rays from surrounding organs. Because after change the body position to left lateral flexion and drinking water, the location of spleen, left lobe of liver and stomach had changed and they could escaped from background ROI. Therefore, modified method could help to minimize the overestimate LVEF (%).