• Journal of Korean Neurosurgical Society
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• v.38 no.2
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• pp.132-135
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• 2005

We report two cases of patients with ruptured vertebral artery dissecting aneurysms that were treated using double overlapping stent placement. Angiography performed immediately after the procedure revealed a significant reduction of aneurysmal filling due to the intraaneurysmal thorombosis. In one case, complete disappearance of the lesion was observed after seven days and in the another one, the size of previous aneurysm sac was decreased on 7th post-procedure day. The reduced stent porosity caused by the overlapping stents, which result in significant hemodynamic changes inside aneurysmal sac, may accelerate intraanuerysmal thromobosis and may be helpful in achieving a more rapid complete occlusion of aneurysm. This double stent method may represent a therapeutic alternatives for dissecting vertebral artery aneurysm in which conventional endovascular techniques or stent supported coil embolization is not considered feasible and surgical treatment is contraindicated.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.150-153
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• 1997

The proposed tracking algorithm approaches geometrical method or position, direction, width of vessel. This algorithm using continuity of vessel in spatial coordinates used to determine direction of the center point, after estimating boundary point in dynamic region. Therefore the tracking of vessel's contour is tracked contour as direction of entire contour in coronary artery. This algorithm is automatically processed by DIP as a compared with conventional method, because searching area varies adaptively to allocate searching region from extracted information at past. And ML estimation expressed robust method or angiography as evaluating sample values after preprocessing.

• Progress in Medical Physics
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• v.32 no.1
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• pp.1-17
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• 2021

The evolution of X-ray computed tomography (CT) has been based on the discovery of X-rays, the inception of the Radon transform, and the development of X-ray digital data acquisition systems and computer technology. Unlike conventional X-ray imaging (general radiography), CT reconstructs cross-sectional anatomical images of the internal structures according to X-ray attenuation coefficients (approximate tissue density) for almost every region in the body. This article reviews the essential physical principles and technical aspects of the CT scanner, including several notable evolutions in CT technology that resulted in the emergence of helical, multidetector, cone beam, portable, dual-energy, and phase-contrast CT, in integrated imaging modalities, such as positron-emission-tomography-CT and single-photon-emission-computed-tomography-CT, and in clinical applications, including image acquisition parameters, CT angiography, image adjustment, versatile image visualizations, volumetric/surface rendering on a computer workstation, radiation treatment planning, and target localization in radiotherapy. The understanding of CT characteristics will provide more effective and accurate patient care in the fields of diagnostics and radiotherapy, and can lead to the improvement of image quality and the optimization of exposure doses.

• Journal of radiological science and technology
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• v.26 no.1
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• pp.63-70
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• 2003

SMAS(Superior Mesenteric Artery Syndrome) is a disease caused by a chronic obstruction of the duodenum(transverse portion), which is hardly detectable. However, it is known that when the superior mesenteric artery and abdominal aorta form a narrow angle, that the transverse portion of the duodenum is pressed down between the superior mesenteric artery and the abdominal aorta, and that this can lead to obstruction of the duodenum. Measuring this angle is a complicated job using conventional angiography, and results often turns out to be inaccurate. In addition, no attempt has been made to determine the value of this angle in Koreans. In this study, we conducted abdominal CT angiography using MIP(maximum intensity projection) on patients with no clinical evidence of SMAS in order to determine the angle at which the superior mesenteric artery branches from the abdominal aorta by using PC based software(Rapidia ver. 1.2) for the image reconstruction. Accordingly, we found that the mean angle between the abdominal aorta and the superior mesenteric artery was $50.05{\pm}15.87^{\circ}$ on average, and that the angle in men($53.64{\pm}16.57^{\circ}$) is higher than in women($46.46{\pm}14.98^{\circ}$). We hope that the angles determined by our study will serve as an important indicator for detecting SMAS.

• Journal of Korean Neurosurgical Society
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• v.61 no.4
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• pp.478-484
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• 2018

Objective : Cerebrovascular disease (CVD) was the third most common cause of death in South Korea in 2014. Evidence from abroad suggests that comprehensive stroke centers play an important role in improving the mortality rate of stroke. However, surgical treatment for CVD is currently slightly neglected by national policy, and there is still regional imbalance in this regard. For this reason, we conducted a survey on the necessity of, and the requirements for, establishing regional comprehensive cerebrovascular surgery centers (CCVSCs). Methods : This investigation was performed using the questionnaire survey method. The questionnaire was consisted with two sections. The first concerned the respondent's opinion regarding the current status of demand and the regional imbalance of cerebrovascular surgery in South Korea. The second section asked about the requirements for establishing regional CCVSCs. We sent the questionnaire to 100 board members of the Korean Society of Cerebrovascular Surgeons. Results : Most experts agreed that cerebrovascular surgery patients were concentrated in large hospitals in the capital area, and 83.6% of respondents agreed that it was necessary to alleviate the regional imbalance of cerebrovascular surgery. With regards to personnel, over 90% of respondents answered that at least two neuro-vascular surgeons and two neuro-interventionists are necessary to establish a CCVSC. Regarding facilities, almost all respondents stated that each CCVSC would require a neuro-intensive care unit and hybrid operating room. The survey asked the respondents about 13 specific neurovascular surgical procedures and whether they were necessary for a regional CCVSC. In the questions about the necessity of cerebrovascular surgical equipment, all seven pieces of equipment were considered essential by all respondents. A further five pieces of equipment were considered necessary on site: computed tomographic angiography, magnetic resonance angiography, conventional angiography, surgical microscope, and surgical navigation. Our results may provide a basis for future policy regarding treatment of cerebrovascular disease, including surgery. Conclusion : Raising the comprehensiveness of treatment at a regional level would lower the national disease burden. Policies should be drafted regarding comprehensive treatment including surgery for cerebrovascular disease, and related support plans should be implemented.

• Journal of Korean Neurosurgical Society
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• v.54 no.2
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• pp.93-99
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• 2013

Objective : Neurologic complications during carotid artery stenting (CAS) are usually associated with distal embolic event. These embolic incident during CAS are highly associated with the carotid plaque instability. The current study was undertaken to identify the angiographic characteristics of carotid plaque vulnerability, which was represented as filling defect in the cerebral protection filters during CAS. Methods : A total of 107 patients underwent CAS with use of a distal protection filter. Angiographic carotid plaque surface morphology was classified as smooth, irregular, and ulcerated. To determine predictable factors of filling defect in the protection filters, 11 variables were retrospectively analyzed which might influence filling defect in the protection filters during CAS. Results : Filling defects during CAS were presented in the 33 cerebral protection filters. In multivariate analysis, angiographic ulceration [odds ratio (OR), 6.60; 95% confidence interval (CI) : 2.24, 19.4; p=0.001], higher stenosis degree (OR, 1.06; 95% CI : 1.00, 1.12; p=0.039), and coexistent thrombus (OR, 7.58; 95% CI : 1.69, 34.05; p=0.08) were highly associated with filling defect in the cerebral protection devices during CAS. Among several variables, angiographic surface ulceration was the only significant factor associated with flow stagnation during CAS (OR, 4.11; 95% CI : 1.33, 12.72; p=0.014). Conclusion : Plaque surface morphology on carotid angiography can be a highly sensitive marker of plaque instability during CAS. The independent risk factors for filling defect in the filter devices during CAS were plaque ulceration, stenosis degree, and coexistent thrombus.

• Investigative Magnetic Resonance Imaging
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• v.9 no.2
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• pp.94-100
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• 2005

Purpose : This study was designed to evaluate the usefulness of 3T-TOF MR angiography (3T-TOF MRA) compared with transcranial Doppler sonography (TCD) and conventional angiography (CA) in patients with suspected cerebral infarction. Materials and Methods : Fifty four patients with clinical symptoms of cerebral infarction were involved in this study, and had undergone 3T-TOF MRA and TCD, with CA in 11 patients. On the basis of divisions of the carotid artery, four groups were designated: group I, both vertebral arteries and basilar artery; group II, segment between 2 cm below bifurcation of common carotid artery and genu portion of internal carotid artery; group III, segment between petrous portion of internal carotid artery and bifurcation of anterior and middle cerebral artery; group IV, from bifurcation of anterior and middle cerebral artery to thier distal branches. Two radiologists retrospectively reviewed the vascular imaging and stenosis in 3T-TOF MRA, TCD, and CA. Results : A total of 432 arteries, 108 in each group, were available. The assessment of vascular imaging quality in 3T-TOF MRA is scored 2.98, 2.96, 2.91, 2.88 in 4 groups, respectively. Agreement among 3T-TOF MR angiography, TCD, and CA was high. Conclusion : 3T-TOF MR angiography may be useful method for the assessment of stenotic lesions of cranial vasculature in patients with cerebral infarction.

• Investigative Magnetic Resonance Imaging
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• v.16 no.1
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• pp.67-75
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• 2012

Purpose : We studied enhanced method to view the vessels in the brain using Magnetic Resonance Angiography (MRA). Noticing that Maximum Intensity Projection (MIP) image is often used to evaluate the arteries of the neck and brain, we propose a new method for view brain vessels to stereo image in 3D space with more superior and more correct compared with conventional method. Materials and Methods: We use 3T Siemens Tim Trio MRI scanner with 4 channel head coil and get a 3D MRA brain data by fixing volunteers head and radiating Phase Contrast pulse sequence. MRA brain data is 3D rotated according to the view angle of each eyes. Optimal view angle (projection angle) is determined by the distance between eye and center of the data. Newly acquired MRA data are projected along with the projection line and display only the highest values. Each left and right view MIP image is integrated through anaglyph imaging method and optimal stereoscopic MIP image is acquired. Results: Result image shows that proposed method let enable to view MIP image at any direction of MRA data that is impossible to the conventional method. Moreover, considering disparity and distance from viewer to center of MRA data at spherical coordinates, we can get more realistic stereo image. In conclusion, we can get optimal stereoscopic images according to the position that viewers want to see and distance between viewer and MRA data. Conclusion: Proposed method overcome problems of conventional method that shows only specific projected image (z-axis projection) and give optimal depth information by converting mono MIP image to stereoscopic image considering viewers position. And can display any view of MRA data at spherical coordinates. If the optimization algorithm and parallel processing is applied, it may give useful medical information for diagnosis and treatment planning in real-time.

• Journal of Chest Surgery
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• v.29 no.8
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• pp.861-866
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• 1996

Surgical angioplasty of isolated stenosis of the left main coronary artery(LMCA) restores a more physiologic flow to the myocardium, allows percutdneous transluminal coronary angioplasty (PTCA) of distal coronary stenoses at a later stage, and is a less time consuming and convenient procedure than the conventional coronary artery bypass grafting(CABG) . Between Jul. 1994 and Dec. 1995, 7 surgical angioplasty had been performed. LMCA stenoses involved ostium in 2 patients, middle third in 3, and dis- tal third in 2. In 2 patients, the origin of left anterior descending coronary artery was involved in conjunction with LMCA. T e additional coronary artery stenoses were found in 2 cases. One patient was emergently operated after coronary angiography following his cardiac arrest. LMCA was approached anteriorly in all patients. The pulmonary artery was transected in 3 patients for a better exposure. The onlay patch consisted or autologous or bovine pericardium. There was no postoperative myocardial infarction or mortality. Left ventricular functions were well preserved in all patients. Postoperative coronary angiography revealed widely patent LMCA in 5 cases, and mild narrowing of distal anastomotic sites in 2 cases. Provided that well defined indications are followed correctly, surgical angioplasty can be a safe alternative to conventional CABG.

• Journal of radiological science and technology
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• v.38 no.2
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• pp.121-126
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• 2015

To image diagnosis in neurovascular diseases using Multi-Detector Computed Tomography(MDCT), injected the same contrast material when inspecting Brain Computed Tomography Angiography(BCTA) to examine radiation dose and Image quality on changing Cerebral Artery CT number by tube voltage. Executed an examination with same condition[Beam Collimation $128{\times}0.6mm$, Pitch 0.6, Rotation Time 0.5s, Slice Thickness 5.0mm, Increment 5.0mm, Delay Time 3.0sec, Care Dose 4D(Demension ; D)] except for tube voltage on 50 call patients for BCTA and divided them into two groups (25 people for a group, group A: 80, group B: 120kVp). From all the acquired images, set a ROI(Region of Interest) on four spots such as left cerebral artery, right cerebral artery, posterior cerebral artery and cerebral parenchyma to compare quantitative evaluation, qualitative evaluation and effective dose after measuring CT number value from Picture Archiving Communications System(PACS). Evaluating images with CT number acquired from BCTA examination, images with 80 kVp was 18% higher in Signal to Noise Ratio and 19% in Contrast to Noise Ratio than those with 120 kVp. It was seen that expose dose was decreased by over 50% with tube voltage 80 kVp than with 120 kVp. Group A (25 patients) was examination with tube voltage 80kVp while group B with 120 kVp to examine radiation dose and Image quality. It is considered effective to inspect with lower tube voltage than with conventional high kVp, which can reduce radiation dose without any affect on diagnosis.