• Korean Journal of Radiology
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• v.1 no.2
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• pp.91-97
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• 2000

Objective: To determine whether the time-intensity curves acquired by test and main dose contrast injections for MR angiography are similar. Materials and Methods: In 11 patients, repeated contrast-enhanced 2D-turbo-FLASH scans with 1-sec interval were obtained. Both test and main dose timeintensity curves were acquired from the abdominal aorta, and the parameters of time-intensity curves for the test and main boluses were compared. The parameters used were arterial and venous enhancement times, arterial peak enhancement time, arteriovenous circulation time, enhancement duration and enhancement expansion ratio. Results: Between the main and test boluses, arterial and venous enhancement times and arteriovenous circulation time showed statistically significant correlation (p < 0.01), with correlation coefficients of 0.95, 0.92 and 0.98 respectively. Although the enhancement duration was definitely greater than infusion time, reasonable measurement of the end enhancement point in the main bolus was impossible. Conclusion: Only arterial and venous enhancement times and arteriovenous circulation time of the main bolus could be predicted from the test-bolus results. The use of these reliable parameters would lead to improvements in the scan timing method for MR angiography.

• Proceedings of the KSMRM Conference
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• 1998.10a
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• pp.114-118
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• 1998

• Korean Journal of Radiology
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• v.2 no.3
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• pp.121-131
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• 2001

Echocardiography and catheterization angiography suffer certain limitations in the evaluation of congenital heart diseases in adults, though these are overcome by MRI, in which a wide field-of view, unlimited multiplanar imaging capability and three-dimensional contrast-enhanced MR angiography techniques are used. In adults, recently introduced fast imaging techniques provide cardiac MR images of sufficient quality and with less artifacts. Ventricular volume, ejection fraction, and vascular flow measurements, including pressure gradients and pulmonary-to-systemic flow ratio, can be calculated or obtained using fast cine MRI, phase-contrast MR flow-velocity mapping, and semiautomatic analysis software. MRI is superior to echocardiography in diagnosing partial anomalous pulmonary venous connection, unroofed coronary sinus, anomalies of the pulmonary arteries, aorta and systemic veins, complex heart diseases, and postsurgical sequelae. Biventricular function is reliably evaluated with cine MRI after repair of tetralogy of Fallot, and Senning's and Mustard's operations. MRI has an important and growing role in the morphologic and functional assessment of congenital heart diseases in adolescents and adults.

• Journal of Oral Medicine and Pain
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• v.25 no.1
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• pp.29-39
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• 2000

Lysyl Oxidase from fetal bovine aorta was purified to homogenity using extraction, Sephacryl S200HR chromatography, Hydropore AX ion-exchange high performance liquid column chromatography, Cibacron blue affinity chromatography, and Sephacryl S-300 HR chromatography in the presence of protease inhibitor. The purified enzyme was active toward lathyritic collagen as well as elastin and was sensitive to aminonitriles such as BAPN. Upon Sephacryl S-300 HR chromatography, the enzyme was eluted as a peak with a $K_{av}$ value of 0.45 (65% of $V_t$ ) and it eluted from high performance liquid ion-exchange column (Hydropore |AX) at single position (ionic strength, I = 0.1~0.15). Once purified, it showed one band upon SDS-PAGE. It migrated to a band the mobility of which corresponded to a Mr of 33,500 upon reduction while it migrated to a 24,500 Mr position under the non-reducing condition. In constrast to other reports, it is concluded that fetal bovine aorta contains only one type of lysy oxidase.

• Journal of Chest Surgery
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• v.27 no.11
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• pp.902-906
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• 1994

Between May 1991 and August 1993, 16 patients underwent repair of complete atrioventricular septal defect without another major anomaly at Cardiovascular Center,Yonsei University College of Medicine. Ages of the patients ranged from 3 months to 38 years with a mean of 42 months. Among 16, 10 patients[63%] are associated with Down`s syndrome. All patients underwent primary repair except and one who received had been repaire of coactation of aorta and patent ductus arteriosus 2 month before. Preoperative mitral valve regurgitation [MR] was evaluated with Doppler echocardiography and angiography which revealed absent or grade I in 1, grade II in 8, grade III in 4, and grade IV in 3. Operative technique was performed under the moderate hypothermic cardiopulmonary bypass with crystalloid cardioplegia. Intraoperative echocardiography was performed epicardial approach [n=7] in the operative table or transthoracic approach [n=9] at intensive care unit. In all patients except 3, MR were improved. But in 3 patients, was not improved or exagerated comparing preoperative one. All of them were died.One patient was showed MR grade IV in intraoperative echocardiography, we re-repaired atriventricular valve with cardiopulmonary bypass. During follow-up period [at a mean of 11 months after repair], doppler echocardiography was performed in all patients. The follow up echocardiography revealed that the degree of MR in immediate postoperative period was not changed except in two patients in whom it was aggravated. Thus it seems that intraoperative and early postoperative echocardiography was employed important role of survival and can be predictable for long term results.

• Journal of Magnetics
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• v.21 no.3
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• pp.421-424
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• 2016

The purpose of this study is to evaluate an effectiveness of switching turbo direction to improve motion artifacts of small bowels and aorta. From June to October 2015, 60 patients suspected of having Crohn's disease were enrolled. The MR Enterography scans were performed using same protocol other than the turbo direction: with the Z phase encoding (group A) and with Y phase encoding (group B). Qualitative analysis of each group was performed to evaluate the effectiveness of switching turbo direction from Z to Y. As a result, the 5-point Likert scale for paired observers were $2.33{\pm}0.88$ for group A and $3.80{\pm}0.85$ for group B on dynamic contrast enhanced coronal images. In conclusion, group B is proved to be superior to group A and can lessen the motion artifacts derived from phase shifts.

• Proceedings of the KSMRM Conference
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• 1999.11a
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• pp.105-105
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• 1999

• Korean Journal of Radiology
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• v.1 no.3
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• pp.142-151
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• 2000

Objective: To determine the optimal scan timing for contrast-enhanced magnetic resonance angiography and to evaluate a new timing method based on the arteriovenous circulation time. Materials and Methods: Eighty-nine contrast-enhanced magnetic resonance angiographic examinations were performed mainly in the extremities. A 1.5T scanner with a 3-D turbo-FLASH sequence was used, and during each study, two consecutive arterial phases and one venous phase were acquired. Scan delay time was calculated from the time-intensity curve by the traditional (n = 48) and/or the new (n = 41) method. This latter was based on arteriovenous circulation time rather than peak arterial enhancement time, as used in the traditional method. The numbers of first-phase images showing a properly enhanced arterial phase were compared between the two methods. Results: Mean scan delay time was 5.4 sec longer with the new method than with the traditional. Properly enhanced first-phase images were found in 65% of cases (31/48) using the traditional timing method, and 95% (39/41) using the new method. When cases in which there was mismatch between the target vessel and the time-intensity curve acquisition site are excluded, erroneous acquisition occurred in seven cases with the traditional method, but in none with the new method. Conclusion: The calculation of scan delay time on the basis of arteriovenous circulation time provides better timing for arterial phase acquisition than the traditional method.

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.96-103
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• 1998

Purpose : To assess the clinical utility of turbo contrast-enhanced magnetic resonance angiography(CE MRA) in the evaluation of the aortic arch and its major branches and to compare the image quality of CE MRA among different coils used. Materials and Methods : Turbo three-phase dynamic CE MRA encompassing aortic arch and its major branches was prospectively performed after manual bolus IV injection of contrast material in 29 patients with suspected cerebrovascular diseases at 1.0T MR unit. the raw data were obtained with 3-D FISH sequence (TR 5.4ms, TE 2.3ms, flip angle 30, slab thickness 80nm, effective slice thickness 4.0mm, matrix size $100{\times}256$, FOV 280mm). Total data acquisition time was 4. to 60 seconds. We subjectively evaluated the imge quality with three-rating scheme : "good" for unequivocal normal finding, "fair" for relatively satisfactory quality to diagnose 'normal' despite intravascular low signal, and "poor" for equivocal diagnosis or non-visualization of the origin or segment of the vessels due to low signal or artifacts which needs catheter angiography. At the level of the carotid bifurcation, it was compared with conventional 2D-TOF MRA image. Overall image quality was also compared visually and quantitatively by measuring signal-to-noise ratios (SNRs) of the ascending aorta, the innominate artery and both common carotid arteries among the three different coils used(CP body array(n=12), CP neck array(n=9), and head-and-neck(n=8). Results : Demonstration of the aortic arch and its major branches was rated as "good" in 55% (16/29) and "fair" in 34%(10/29). At the level of the carotid bifurcation, image quality of turbo CE MRA was same as or better than conventional 2D-TOF MRA in 65% (17/26). Overall image quality and SNR were significantlygreater with CP body array coil than with CP neck array or head-and-neck coil. Conclusions : Turbo CE MRA can be used as a screening exam in the evaluation of the major branches of the aortic arch from their origin to the skull base. Overall imagequality appears to be better with CP body array coil than with CP neck array coil or head-and-neck coil.

• Journal of Chest Surgery
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• v.35 no.8
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• pp.599-604
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• 2002

Acute or chronic aortic dissection may lead to the rupture, which is the major cause of death. A dissecting aneurysm of ascending aorta(Stanford type A dissection) can rupture into the superior vena cava producing a aortocaval fistula, which is rare, but has been reported mostly in the cases of abdominal aortic aneurysm. We report a case of 67-year-old man with type A chronic dissection and aortocaval fistula, presenting symptoms of superior vena syndrome. The preoperative diagnosis was composed of radiologic examinations, including computed tomography, magnetic resonance imaging angiography and aortography. The dissecting aneurysm was resected and replaced, and the aortocaval fistula was repaired under deep hypothermic circulatory arrest. The details are described here.