• The KIPS Transactions:PartB
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• v.12B no.5 s.101
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• pp.543-552
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• 2005

This paper proposes the extraction of coronary arteries based on DSA(Digital Subtraction Angiography) through a texture analysis of background in the angiography. DSA is a well established modality for the visualization of coronary arteries. DSA involves the subtraction of a mask image - an image of the heart before injection of contrast medium - from live image. However, this technique is sensitive to the movement of background and can result to a wrong detection by the variance of background gray-level intensity between two images. Therefore, this paper solves a structural problem resulted from a background movement bV selecting an image which has the least difference of movement through an analysis of the similarity of background texture and proposes a method to extract only the blood vessel efficiently through local gray-level correction of the selected image. Using the coronary angiogram of 5 patients clinical data, we proved that the proposed method has the lower false-detection rate, approximately $2\%$, and the higher accuracy than the existing methods.

• Journal of Korean Neurosurgical Society
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• v.30 no.sup1
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• pp.165-169
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• 2001

Apatient, 51 years old woman, had suffered form headache and decrease of visual acuity. She had $3{\times}3cm$ sized giant aneurysm originated in cavernous and clinoid portion of left ICA(C4,C5) in the cerebral angiography. Before craniotomy, left CCA was exposed and 6F double lumen catheter was inserted in left ICA through the sheath. Pre-operative angiography was done. balloon catheter was positioned at the petrous portion of ICA. Eyebrow approach was done and giant aneurysm was exposed. The proximal blood flow was controlled with balloon dilatation and suction and decompression was tried, then multiple clips were applied. The loss of distal blood flow under intra-operative angiography was notified after clipping. The position of clips were repositioned to preserve blood flow & the rich flow was confirmed at distal part of clipping. In the post-operative cerebral angiography, the same finding was shown.

• Journal of Korean Neurosurgical Society
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• v.29 no.3
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• pp.345-352
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• 2000

Objective : The purpose of this study was to compare computed tomographic angiography(CTA) with conventional cerebral angiography(CCA) and to assess usefulness of CTA in detection and anatomic definition of intracranial aneurysms of the circle of Willis in subarachnoid hemorrhage. Patients and Methods : Fifty consecutive patients with known or suspected intracranial saccular aneurysms underwent CTA with preoperative CCA from 1997 to 1999. Using surface shaded display post-processing technique, CTA was interpreted for the presence, location of aneurysms and anatomic features. The image obtained with CTA was then compared with CCA image. Results : In 47 patients, CCA revealed 57 cerebral aneurysms and CTA revealed 54 aneurysms. Two of the 57 cerebral aneurysms were located outside of the imaging volume of CTA and one case was misdiagnosed. The sensitivity of CTA was 94.7% and the specificity was 100%. The results obtained with CTA were, compared with the results obtained with CCA, equal in determining dome shape, direction and lobularity. However, CTA provided a 3-dimensional representation of aneurysmal lesion very useful for surgical planning. Moreover, CTA was useful for rapid and relatively noninvasive detection of aneurysms in the circle of Willis. Conclusion : CTA can be a diagnostic tool for the patients with acute subarachnoid hemorrhage due to a ruptured aneurysm of the circle of Willis and provides adequate anatomic detail for surgical planning, especially to complex cerebral aneurysms. However, we think CCA is necessary because of CTA limitations including its difficulty in detecting unusually located aneurysms(including those in cavernous sinus or distal artery) and combined vascular lesion (including arteriovenous malformation) and acquiring dynamic flow information.

• Journal of Korean Neurosurgical Society
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• v.65 no.5
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• pp.710-718
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• 2022

Objective : Although endovascular treatment for intracranial aneurysms is considered effective and safe, its durability is still debated. Also, few studies have described angiographic follow-up plan after endovascular treatment of intracranial aneurysm, especially in ruptured cases. Hence, we report the long-term results of follow-up angiography protocol. Methods : Radiological records of 639 cases of coil embolization with ruptured aneurysms from March 2003 to December 2016 were retrospectively reviewed. Patients who received treatment of a saccular aneurysm less than 7 mm resulted with near complete occlusion were included. Two hundred thirty-eight aneuryms which received the follow-up angiography at least once were enrolled. We classified four periods of follow-up as follows : post-treatment 1 year (defined as the first period), from 1 to 2 years (the second period), 2 to 5 years (the third period), and over 5 years (long-term). Results : We identified 14 cases (6.4%) of recurrence from 218 aneurysms in follow-up angiography in the first period. Among 143 aneurysms in the second period, five cases (3.5%) of recurrence were identified. There were no findings suspicious of recanalization in 97 patients in the third period. Of the total 238 cases, there were 19 recurrences, for a recurrence rate of 8.0%. Six (31.6%) out of 19 recurrences showed a tendency toward repeat recurrences even after additional treatment. Twenty-eight received long-term follow-up over 5 years and there was no recurrence. Conclusion : Most of the recurrence were found during the first and the second year. We suggest that at least one digital subtraction angiography examination may be necessary around post-treatment 2 years, especially in ruptured cases. If the angiographic results are favorable at 2 years post-treatment, long-term result should be favorable.

• Journal of the Korean Society of Radiology
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• v.83 no.1
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• pp.3-27
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• 2022

Cardiac CT has been proven to provide diagnostic and prognostic evaluation of coronary artery disease for cardiovascular risk stratification and treatment decision-making based on rapid technological development and various research evidence. Coronary CT angiography has emerged as a gateway test for coronary artery disease that can reduce invasive angiography due to its high negative predictive value, but the diagnostic specificity is relatively low. However, coronary CT angiography is likely to overcome its limitations through functional evaluation to identify the hemodynamic significance of coronary artery disease by analyzing myocardial perfusion and fractional flow reserve through cardiac CT. Recently, studies have been actively conducted to incorporate artificial intelligence to make this more objective and reproducible. In this review, functional imaging techniques of cardiac computerized tomography are explored.

• Journal of the Korean Society of Radiology
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• v.85 no.2
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• pp.258-269
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• 2024

Treatment of patients with coronary artery disease commonly involves the use of balloon-expandable stent placements, currently recognized as the most prevalent approach for coronary artery revascularization. Nevertheless, the occurrence of restenosis remains a significant complication following percutaneous coronary interventions. The diagnostic role of coronary CT angiography (CCTA) in detecting stent restenosis has limitations primarily attributable to challenges in accurately discerning the lumen, due to issues such as blooming and motion artifacts. As a result, many cases often necessitate a transition to conventional coronary angiography. However, recent advancements in CT technology have led to notable improvements in both sensitivity and specificity, underscoring the growing significance of CCTA as a diagnostic tool. The consistent reporting of high negative predictive value is particularly noteworthy. This review aims to explore the historical context, current status, and recent trends in diagnosing coronary artery stent restenosis using CCTA.

• Investigative Magnetic Resonance Imaging
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• v.13 no.2
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• pp.152-160
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• 2009

Purpose : To intra-individually compare diagnostic accuracy of high-resolution contrast-enhanced magnetic resonance angiography (CE-MRA) with computed tomography angiography (CTA) and digital subtraction angiography (DSA) for the assessment of supraaortic steno-occlusive disease. Materials and Methods : Twenty-eight patients (20 men, 8 women, 53-79 years of age) underwent supraaortic CE-MRA, CTA and DSA. CE-MRA was performed on two 1.5T MR scanners (voxel dimension: $0.66{\times}0.66{\times}1.1$ or $1.2\;mm^3$), and CTA on 64-slice CT scanners (voxel dimension: $0.42{\times}0.42{\times}0.63\;mm^3$). All the three examinations were completed within 40 days (median 19 days; range 1-40 days). Retrospective evaluation and measurement of diameter of 6 extracranial and 9 intracranial arterial segments was done by 2 experienced radiologists. Results: A total of 420 arterial segments were examined by CE-MRA, CTA and DSA. On DSA, 34 stenoocclusive lesions were noted at extracranial (n= 19) and intracranial (n = 15) vessels. For extracranial stenosis greater than 70%, sensitivity, specificity, positive predictive value (PPV) and negative predictive values (NPV) were 94.7%, 98.7%, 90.0% and 99.3% on CE-MRA, and 94.7%, 99.3%, 94.7% and 99.3% on CTA. For intracranial stenosis greater than 50%, sensitivity; specificity, PPV and NPV were 93.3%, 98.3%, 77.8%and 99.6% on CE-MRA, and 86.7%, 97.9%, 72.2% and 99.1 % on CTA, with DSA as the standard of reference. Conclusion : Supraaortic CE-MRA is as reliable as CTA in depicting the arterial stenosis, and is effective in screening of significant stenosis of both extracranial and intracranial arterial stenosis.

• Journal of radiological science and technology
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• v.34 no.2
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• pp.105-116
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• 2011

In this study, we present the measurements of effective dose from CT of head & neck region. A series of dose measurements in anthropomorphic Rando phantom was conducted using a radio photoluminescent glass rod dosimeter to evaluate effective doses of organs of head and neck region from the patient. The experiments were performed with respect to four anatomic regions of head & neck: optic nerve, pons, cerebellum, and thyroid gland. The head & neck CT protocol was used in the single scan (Brain, 3D Facial, Temporal, Brain Angiography and 3D Cervical Spine) and the multiple scan (Brain+Brain Angiography, Brain+3D Facial, Brain+Temporal, Brain+3D Cervical spine, Brain+3D Facial+Temporal, Brain+3D Cervical Spine+Brain Angiography). The largest effective dose was measured at optic nerve in Brain CT and Brain Angiography. The largest effective dose was delivered to the thyroid grand in 3D faical CT and 3D cervical spine, and to the pons in Temporal CT. In multiple scans, the higher effective dose was measured in the thyroid grand in Brain+3D Facial, Brain+3D Cervical Spine, Brain+3D Facial+Temporal and Brain+3D Cervical Spine+Brain Angiography. In addition, the largest effective dose was delivered to the cerebellum in Brain CT+Brain Angiography CT and higher effective dose was delivered to the pons in Brain+Temporal CT. The results indicate that in multiple scan of Brain+3D Cervical Spine+Brain Angiography, effective dose was 2.52 mSv. This is significantly higher dose than the limitation of annual effective dose of 1 mSv. The effective dose to the optic nerve was 0.31 mSv in Brain CT, which shows a possibility of surpassing the limitation of 1 mSv by furthre examination. Therefore, special efforts should be made in clinical practice to reduce dose to the patients.

• Journal of Trauma and Injury
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• v.19 no.2
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• pp.196-200
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• 2006

We report a case of celiac artery dissection after abdominal blunt trauma. A 29-year-old man visited the emergency room for acute left periumbilical pain after abdominal blunt trauma from his child. Computed tomography showed a wedge-shaped splenic infarction with splenic artery thrombus. He was hospitalized for careful observation, and after two days, follow-up computed tomographic angiography showed a progressed celiac artery dissection that involved common hepatic artery and an increased extent of splenic infarction. He underwent conventional angiography, and a self-expandable stent was placed between the celiac axis and the common hepatic artery. After two days, follow-up computed tomographic angiography showed good hepatic arterial blood flow via the stent and no progression of splenic infarction. After ten days, he was discharged without complications.

• Journal of Korean Neurosurgical Society
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• v.54 no.3
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• pp.236-238
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• 2013

Rapidly developed de novo aneurysm is very rare. We present a rapidly developed and ruptured de novo anterior communicating aneurysm 8 days after the rupture of another aneurysm. This de novo aneurysm was not apparent in the initial 3-dimensional computed tomography and digital subtraction angiography. We reviewed the literature and discussed possible mechanisms for the development of this de novo aneurysm.