• Proceedings of the KSMRM Conference
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• 1999.11a
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• pp.46-46
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• 1999

• 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%.

• Investigative Magnetic Resonance Imaging
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• v.21 no.3
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• pp.131-138
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• 2017

Purpose: To optimize the timing of scans using cardiac magnetic resonance contrast-enhanced timing robust angiography (CMR-CENTRA) for electroanatomic mapping (EAM) of the right atrium (RA) and left atrium (LA) in patients with atrial fibrillation (AF). Materials and Methods: Fifty patients with AF (38 men; mean age, $59.6{\pm}9.3years$) underwent CMR-CENTRA in preparation for EAM. The CMR-CENTRA data were acquired at five different scan times: 0 seconds, 5 seconds, 10 seconds, 15 seconds, and 20 seconds after an intravenous injection of contrast media. To evaluate the degree of contrast enhancement, right atrial relative contrast (RA-RC) and left atrial relative contrast (LA-RC) on the CMR-CENTRA scans were assessed at each time point. The three-dimensional (3D) reconstruction of the RA and LA for the EAM system was performed using the CMR-CENTRA data. Results: A CMR-CENTRA at a scan time of 10 seconds showed significantly greater LA-RC (P < 0.05) compared with all other scan times. A CMR-CENTRA at a scan time of 15 seconds showed significantly greater RA-RC (P < 0.05) compared with all other scan times. In the 3D reconstruction of the RA, the success rates of CMR-CENTRA at scan times of 10 seconds and 15 seconds were 18% and 100%, respectively. In the 3D reconstruction of the LA, the success rates of CMR-CENTRA at 10- and 15-second scan times were 100%. Conclusion: The CMR-CENTRA data acquired at 15 seconds after the injection of contrast media is appropriate for the preparation of an EAM system that is focused on the RA and LA in patients with AF.

• Investigative Magnetic Resonance Imaging
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• v.21 no.2
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• pp.82-90
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• 2017

Purpose: This study investigated the MRI, MR angiography (MRA) and MR perfusion findings of seizure-related cerebral cortical lesions during the periictal period. Materials and Methods: From a retrospective review of the institutional database between 2011 and 2014, a total of 21 patients were included in this study. Two radiologists assessed periictal MRI, including MRA and MR perfusion, in patients with seizure-related cortical lesions. The parameters examined include: location of cortical abnormality, multiplicity of the affected cortical region, cerebral vascular dilatation, perfusion abnormality and other parenchymal lesions. Results: All patients showed T2 hyperintense cerebral cortical lesions with accompanying diffusion restriction, either unilateral (18/21, 85.7%) or bilateral (3/21, 14.3%). Of the 21 patients enrolled, 10 (47.6%) had concurrent T2 hyperintense thalamic lesions, and 10 (47.6%) showed hippocampal involvement. Of the 17 patients (81%) who underwent MRA, 13 (76.5%) showed vascular dilatation with increased flow signal in the cerebral arteries of the affected cortical regions. On MR perfusion, all 5 patients showed cortical hyperperfusion, corresponding to the region of cortical abnormalities. Conclusion: Seizure-related cerebral cortical lesions are characterized by T2 and diffusion hyperintensities, with corresponding cerebral hyperperfusion and vascular dilatation. These findings can be helpful for making an accurate diagnosis in patients with seizure.

• 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 Korean Neurosurgical Society
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• v.39 no.5
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• pp.355-359
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• 2006

Objective : The purpose of our study is to examine the clinical significance of vertebrobasilar artery[VBA] fenestration and duplication. In addition, we review its incidence and pathogenesis. Methods : Cerebral angiography was performed in 803 patients and magnetic resonance angiography[MRA] in 880; the patients had or were suspected to have cerebrovascular disease. We retrospectively reviewed angiography and MRA. Results : Fifteen patients [eight men, seven women, 3 to 77 years of age, median age = 58 years] had a VBA fenestration and duplication. Seven [7/803 = 0.87%] of the patients undergoing cerebral angiography revealed fenestrations and one duplication of VBA. Ten patients [10/880 = 114%] among 880 patients that underwent MRA demonstrated fenestration of basilar artery[BA]. Two of 66 patients that underwent both conventional cerebral angiography and cranial MRA showed a fenestration of BA. Twelve fenestrations were located in the proximal portion of the BA and one was in the mid portion of the BA. One vertebral artery[VA] fenestration was located in the intracranial portion of the right VA, and one VA duplication was at the level of $C_{1-2}$ in the left VA. Conclusion : In addition to medial defects, flow phenomena at the proximal end of fenestrations, where hemodynamic stress and increased turbulence are present, may contribute to aneurysm formation. And arterial fenestration is a predisposing factor in vascular injury and cerebral ischemia.

• Journal of Korean Neurosurgical Society
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• v.40 no.2
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• pp.74-78
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• 2006

Objective : We examined the incidence of fenestration in the proximal segment of the anterior cerebral artery[ACA] and reviewed its clinical significance. Methods : Cerebral angiography was performed in 843 patients and magnetic resonance angiography[MRA] in 1,787; all patients had, or were suspected to have, cerebrovascular disease. We subsequently reviewed the angiography and MRA data. Results : Fourteen patients [six men and eight women, $35{\sim}81$ years of age, median age = 67 years] had proximal ACA fenestrations. Three of the 843 patients [0.36%] undergoing cerebral angiography had fenestrations of proximal ACA as did eleven of the 1,787 MRA patients [0.62%]. Seven fenestrations were located on the right side and seven fenestrations were located on the left side. The fenestrated ACA in one patient was associated with a saccular aneurysm at its proximal end. None of the 120 patients who underwent both conventional cerebral angiography and cranial MRA showed fenestration of proximal ACA. Conclusion : Although fenestration of ACA has little clinical significance, knowledge and recognition of this condition is important in the interpretation of cerebral images, especially during neurosurgical procedures.

• Investigative Magnetic Resonance Imaging
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• v.20 no.3
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• pp.141-151
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• 2016

Purpose: Advances of magnetic resonance imaging (MRI), especially that of the Ultra-High Field (UHF) MRI will be reviewed. Materials and Methods: Diffusion MRI data was obtained from a healthy adult young male of age 30 using a 7.0T research MRI scanner (Magnetom, Siemens) with 40 mT/m maximum gradient field. The specific imaging parameters used for the data acquisition were a single shot DW echo planar imaging. Results: Three areas of the imaging experiments are focused on for the study, namely the anatomy, angiography, and tractography. Conclusion: It is envisioned that, in near future, there will be more 7.0T MRIs for brain research and explosive clinical application research will also be developed, for example in the area of connectomics in neuroscience and clinical neurology and neurosurgery.

• Journal of Korean Neurosurgical Society
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• v.45 no.1
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• pp.50-52
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• 2009

A 31-year-old man presented with dull headache and memory disturbance lasting for one week. Computed tomographic scans revealed acute hydrocephalus. The cerebrospinal fluid contained 53 leukocytes/$mm^3$, with a mononuclear preponderance and no erythrocytes. Magnetic resonance imaging revealed hydrocephalus and leptomeningeal enhancement. Magnetic resonance angiography and digital subtraction angiography showed supraclinoid occlusion of the right internal carotid artery, which resembled unilateral moyamoya disease. Neuroendoscopic biopsy of a lesion in the septum pellucidum revealed noncaseating granulomas, which was consistent with sarcoidosis. The patient was successfully managed with intravenous methylprednisolone and ventriculoperitoneal shunting. To our knowledge, this is the first case of moyamoya-like vasculopathy associated with neurosarcoidosis.

• Journal of Korean Neurosurgical Society
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• v.56 no.3
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• pp.278-280
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• 2014

A 66-year-old man presented with typical trigeminal neuralgia (TN). Magnetic resonance angiography (MRA) revealed a primitive trigeminal artery (PTA) that came into contact with the trigeminal nerve. Based on MRA, we performed microvascular decompression (MVD). In the operational field, we confirmed the PTA location and performed MVD successfully. Postoperatively, the patient's pain subsided without any complications.