• Journal of KIISE:Software and Applications
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• v.30 no.12
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• pp.1247-1254
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• 2003

Currently. the north american symptomatic carotid endarterectomy trial, european carotid surgery trial, and common carotid method are used to measure the carotid stenosis for determining candidate for carotid endarterectomy using the projection angiography from different modalities such as digital subtraction angiography. rotational angiography, computed tomography angiography and magnetic resonance angiography. A new computerized carotid stenosis measuring system was developed using MR angiography axial image to overcome the drawbacks of conventional carotid stenosis measuring methods, to reduce the variability of inter-observer and intra-observer. The gray-level thresholding is one of the most popular and efficient method for image segmentation. We segmented the carotid artery and lumen from three-dimensional time-of-flight MRA axial image using gray-level thresholding technique. Using the measured intima-media thickness value of common carotid artery for each cases, we separated carotid artery wall from the segmented carotid artery region. After that, the regions of segmented carotid without artery wall were divided into region of blood flow and plaque. The calculation of carotid stenosis degree was performed as the following; carotid stenosis grading is(area measure of plaque/area measure of blood flow region and plaque) * 100%.

• Journal of the Korean Institute of Telematics and Electronics
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• v.20 no.1
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• pp.63-71
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• 1983

A dye-edge tracking algorithm was used to determine the corresponding points in the two images(anterior-posterior and lateral) of the digital subtraction biplane angiography. This correspondence was used to reconstruct three dimensional images of cerebral artery in a dog experiment. The method was tested by comparing the measured image of oblique view with the computed reconstructed image. For the present study, we have developed three new algorithms. The first algorithm is to determine the corresponding dye-edge points using the fact the dye density at the moving edge avows the same changing pattern in the two projection views. This moving pattern of dye-edge density is computed using a matching method of cross-correlation for the two sequential frames' dye density. The second algorithm is for simplified perspective transformation, and the third one is to identify the specific corresponding points on the small vessels. The present method can be applied to compute the blood velocity using the dye-edge displacement and the three- dimensional distance data.

• Journal of Magnetics
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• v.20 no.1
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• pp.40-46
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• 2015

This study investigated the accuracy of magnetic resonance angiography (MRA) and computed tomography angiography (CTA) in terms of reflecting the actual vascular length. Three-dimensional time of flight (3D TOF) MRA, 3D contrast-enhanced (CE) MRA, volume-rendering after CTA and maximum intensity projection were investigated using a flow model phantom with a diameter of 2.11 mm and area of $0.26cm^2$. 1.5 and 3.0 Tesla devices were used for 3D TOF MRA and 3D CE MRA. CTA was investigated using 16 and 64 channel CT scanners, and the images were transmitted and reconstructed by volume-rendering and maximum intensity projection, followed by conduit length measurement as described above. The smallest 3D TOF MRA measure was $2.51{\pm}0.12mm$ with a flow velocity of 40 cm/s using the 3.0 Tesla apparatus, and $2.57{\pm}0.07mm$ with a velocity of 71.5 cm/s using the 1.5 Tesla apparatus; both images were magnified from the actual measurement of 2.11 mm. The measurement with the 16 channel CT scanner was smaller ($3.83{\pm}0.37mm$) than the reconstructed image on maximum intensity projection. The images from CTA from examination apparatus and reconstruction technique were all larger than the actual measurement.

• Journal of Korean Neurosurgical Society
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• v.41 no.4
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• pp.230-235
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• 2007

Objective : We investigated the incidence of the vascular abnormalities associated with spontaneous intracerebral hemorrhage [ICH] using three-dimensional computed tomographic angiography [3D-CTA]. Methods : We prospectively assessed consecutive 76 patients with spontaneous intracerebral hemorrhage [ICH] who underwent 3D-CTA between June 2003 and May 2005. The patients with a recent history of trauma or mainly subarachnoid hemorrhage were excluded. We investigated relationship between vascular abnormality and ICH location. The findings of 3D-CTA were classified as one of three patterns with ICH; type A [without evidence of vascular abnormality], type B [with no vascular abnormality as the source of hemorrhage, but with incidental vascular abnormality], and type C [presence of a vascular abnormality as the source of hemorrhage]. Results : Sites of ICH were lobar 26, basal ganglia 23, thalamus 17, posterior fossa 6 and dominant intraventricular hemorrhage [IVH] 4. Among 76 patients, sixteen [21.1%] vascular abnormalities were noted excluding 13 cases of stenoocclusive disease. Sixteen cases included 6 cases of cerebral aneurysms [7.9%], 5 moyamoya diseases [6.6%], 4 arteriovenous malformations [5.3%] and 1 dural sinus thrombosis [1.3%]. Lobar ICH [30.8%] had a higher vascular abnormalities than other types, and younger age [<40] group had a higher incidence of vascular abnormalities than old age group. The patterns of 3D-CTA include sixty cases [79.0%] of type A, 6 cases [7.8%] of type Band 10 cases [13.2%] of type C. The vascular abnormalities were found in 8 [13.5%] of 59 hypertensive patients and 8 [47.0%] of 17 non-hypertensive patients [p=0.006]. Conclusion : 3D-CT angiography is considered a useful screening tool for ICH patients with suspected cerebrovascular abnormalities and should be considered in such clinical settings, especially in lobar type and in non-hypertensive younger patients.

• Korean Journal of Veterinary Research
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• v.59 no.2
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• pp.55-58
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• 2019

This study was performed to examine the visualization and anatomical variants of the hepatic artery with dual-phase computed tomography (CT) angiography and three-dimensional volume rendering imaging analysis in clinically normal dogs. Seven healthy beagle dogs were enrolled and underwent dual CT angiography. Arterial phase images could be obtained with multi-detector CT angiography using the fixed-scan method in these dogs. Contrast enhancement of the hepatic parenchyma was quite minimal because of the unique blood supply system of the liver. In most dogs, the main hepatic arterial branches were the right lateral branch, left branch, and right medial branch. Although hepatic arterial variation appears to be common in dogs, only one dog in this study had the caudate lobar branch as the first branch of the hepatic artery. Further study on a larger number of dogs with CT images will be needed to identify and classify the pattern of hepatic arterial variations.

• Journal of Korean Neurosurgical Society
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• v.65 no.2
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• pp.245-254
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• 2022

Objective : The etiology of angiographically occult spontaneous subarachnoid hemorrhage (AOsSAH) is unclear. Three-dimensional (3D) high-resolution vessel wall magnetic resonance imaging (HVM) might be useful in detecting the hidden arterial wall angiopathy in patients with AOsSAH. We aimed to demonstrate the feasibility of HVM for detecting the arterial cause of AOsSAH. Methods : Patients, who were diagnosed with AOsSAH in the first evaluations and underwent HVM, were enrolled. Their clinical and radiologic data were retrospectively reviewed. Especially, focal enhancement of arterial wall on HVM and repetitive catheterized angiograms were precisely compared. Results : Among 251 patients with spontaneous SAH, 22 patients were diagnosed with AOsSAH in the first evaluations (8.76%). After excluding three patients who did not undergo 3D-HVM, 19 patients were enrolled and classified as convexal (n=2) or perimesencephalic (n=4), and diffuse (n=13) groups. In convexal and perimesencephalic groups, no focal enhancement on HVM and no positive findings on repetitive angiography were noted. In diffuse group, 10 patients showed focal enhancement of arterial wall on HVM (10/13, 76.9%). Repeated angiography with 3D reconstruction revealed four patients of angiographically positive causative arteriopathy and possible lesion in one case in the concordant location of intramural enhancement on 3D-HVM (5/10, 50%). Three of them were treated with endovascular stent insertion. All patients, except one, recovered with good clinical outcome (3-month modified Rankin score, 0 and 1). Conclusion : 3D-HVM was useful in detecting hidden true arteriopathy in AOsSAH. It may provide new insights into the etiologic investigation of AOsSAH by proving information about the arterial wall status.

• Journal of Korean Neurosurgical Society
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• v.39 no.6
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• pp.427-431
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• 2006

Objective : The purpose of this study is to assess the usefulness of three-dimensional computed tomography angiography [3D-CTA] as a postoperative follow-up examination after intracranial aneurysms have been clipped. Methods : Between January 2002 and June 2005, 522 consecutive patients received treatment for intracranial aneurysms. A retrospective analysis of 310 patients with postoperative 3D-CTAs was performed to evaluate aneurysmal remnants and de novo aneurysms. This study was conducted in 271 patients with at least immediate and 6-month routine 3D-CT As for postoperative clipped aneurysm and 39 patients with 3D-CTAs for clipped aneurysm before 2002 when there was no 3D-CTA in our hospital. Results : Eight patients had abnormal CT angiographic findings. Aneurysm remnants were revealed in 4 patients and de novo aneurysms were discovered in 5 patients. Two patients were found at the postoperative 6-month 3D-CTA performed routinely. In 1 patient, the aneurysm was demonstrated on the way to the examination of syncope. In 2 patients, the author recommended 3D-CTA although there was no symptom because the patients had visited our institute long time ago [5.1, 4.5 years]. Of the 8 patients, 2 remnants and 1 de novo aneurysm were treated by endovascular treatment. Three de novo aneurysms at the middle cerebral artery and 1 pericallosal artery aneurysm were treated by direct clipping because these aneurysms were not suitable for the endovascular treatment in point of anatomical configuration. One patient with both remnant and de novo aneurysm was treated conservatively. Conclusion : 3D-CTA is an available, non-invasive diagnostic tool for the postoperative follow-up examination of aneurysmal state in patients after clipping.

• Journal of Korean Neurosurgical Society
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• v.67 no.1
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• pp.115-121
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• 2024

After treatment of unilateral vertebral artery dissecting aneurysm (VADA), de novo VADA rarely occurs on the contralateral side. In this article, we report a case of subarachnoid hemorrhage (SAH) due to de novo VADA in the contralateral vertebral artery (VA) 3 years after parent artery occlusion of unilateral VADA, with a review of the literature. A 47-year-old woman was admitted to our hospital complaining of headache and impaired consciousness. Head computed tomography showed SAH, and three-dimensional computed tomography angiography showed a fusiform aneurysm in the left VA. We performed an emergency parent artery occlusion. Three years and 3 months after the initial treatment, the patient presented to our hospital with complaints of headache and neck pain. Magnetic resonance imaging revealed SAH, and magnetic resonance angiography revealed de novo VADA in the right VA. We performed a stent-assisted coil embolization. The patient had a good postoperative course and was discharged with a modified Rankin scale score of 0. Long-term follow-up is necessary in patients with VADA because contralateral de novo VADA can develop even several years after the initial treatment.

• Korean Journal of Radiology
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• v.24 no.7
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• pp.681-689
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• 2023

Objective: Three-dimensional rotational angiography (3D-RA) is increasingly used for the evaluation of intracranial aneurysms (IAs); however, radiation exposure to the lens is a concern. We investigated the effect of head off-centering by adjusting table height on the lens dose during 3D-RA and its feasibility in patient examination. Materials and Methods: The effect of head off-centering during 3D-RA on the lens radiation dose at various table heights was investigated using a RANDO head phantom (Alderson Research Labs). We prospectively enrolled 20 patients (58.0 ± 9.4 years) with IAs who were scheduled to undergo bilateral 3D-RA. In all patients' 3D-RA, the lens dose-reduction protocol involving elevation of the examination table was applied to one internal carotid artery, and the conventional protocol was applied to the other. The lens dose was measured using photoluminescent glass dosimeters (GD-352M, AGC Techno Glass Co., LTD), and radiation dose metrics were compared between the two protocols. Image quality was quantitatively analyzed using source images for image noise, signal-to-noise ratio, and contrast-to-noise ratio. Additionally, three reviewers qualitatively assessed the image quality using a five-point Likert scale. Results: The phantom study showed that the lens dose was reduced by an average of 38% per 1 cm increase in table height. In the patient study, the dose-reduction protocol (elevating the table height by an average of 2.3 cm) led to an 83% reduction in the median dose from 4.65 mGy to 0.79 mGy (P < 0.001). There were no significant differences between dose-reduction and conventional protocols in the kerma area product (7.34 vs. 7.40 Gy·cm², P = 0.892), air kerma (75.7 vs. 75.1 mGy, P = 0.872), and image quality. Conclusion: The lens radiation dose was significantly affected by table height adjustment during 3D-RA. Intentional head off-centering by elevation of the table is a simple and effective way to reduce the lens dose in clinical practice.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.2
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• pp.196-204
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• 2016

World Health Organization reported that heart-related diseases such as coronary artery stenoses show the highest occurrence rate which may cause heart attack. Using Computed Tomography angiography images will allow radiologists to detect and have intervention by creating 3D roadmapping of the vessels. However, it is often complex and difficult do reconstruct 3D vessel which causes very large amount of time and previous researches were studied to segment vessels more accurate automatically. Therefore, in this paper, Region Competition, Geodesic Active Contour (GAC), Multi-atlas based segmentation and Active Shape Model algorithms were applied to segment aortic root from CTA images and the results were analyzed by using mean Hausdorff distance, volume to volume measure, computational time, user-interaction and coronary ostium detection rate. As a result, Extracted 3D aortic model using GAC showed the highest accuracy but also showed highest user-interaction results. Therefore, it is important to improve automatic segmentation algorithm in future