• Journal of the Korean Society of Radiology
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• v.81 no.5
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• pp.1053-1068
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• 2020

In accordance with the new healthcare policy of government (Moon Jae-In Care) to strengthen health insurance coverage, the National Health Insurance (NHI) coverage of brain magnetic resonance imaging (MRI), brain/neck MR angiography (MRA), and head and neck MRI have been expanded since 2018 in Korea. This article has been reviewed focusing on the "Detailed matter concerning criteria and method for providing reimbursed services in the NHI. Some revisions" regarding reimbursement for MRI, which was revised from October 2018 to April 2020 and is currently in effect. It included the MRI reimbursement system in Korea, recent adjustment of the reimbursement coverage for patients with headache or dizziness, and reimbursement coverage, standard imaging, and radiologic report of brain MRI, brain/neck MRA and head and neck MRI. This article could help radiologists gain knowledge on health insurance to protect the expertise of the radiologist and to play a leading role in the hospital. As the policy changes, detailed matter concerning criteria and method for providing reimbursed services in the NHI may be revised. Therefore, radiologists should update issues related to insurance reimbursement for MRI continuously.

• Journal of Korean Neurosurgical Society
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• v.55 no.5
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• pp.273-276
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• 2014

Aneurysmal subarachnoid hemorrhage (SAH) during pregnancy is quite rare, however it has a high maternal mortality rate. A pregnant woman in the 16th gestational week was admitted to our hospital with a drowsy level of consciousness. A brain magnetic resonance (MR) image showed hemorrhage on the prepontine cistern, and both sylvian fissures, and MR angiography and cerebral digital subtraction angiography demonstrated an aneurysm at the left posterior inferior cerebellar artery (PICA). We performed endovascular coil embolization attempting to minimize radiation exposure. She was discharged with no neurologic deficit and delivered a healthy baby by cesarean section at the 38th week of gestation. This case study reported the shortest gestational period and this is the first report on an aneurysmal rupture arising from PICA which was treated using an endovascular method. Using an appropriate technique for reduced radiation exposure to the fetus and limited alterations in maternal-fetal physiology, endovascular coil embolization could guarantee good results in treatment of aneurysmal SAH in pregnant women.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.104-104
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• 2002

목적： SAAV sequence를 이용하여 동시에 획득한 동맥과 정맥의 두 MRA 영상을 Color Mapping으로 동맥과 정맥을 구분하여 한 영상에 나타냄으로써 AVM 이나 DAVF 등과 같은 혈관질환의 임상적 진단 및 치료에 도움을 주고자 하였다. 대상 및 방법： 일반적으로 MRA 영상은 사전 포화방법(presaturation)을 이용한 2D TOF 기법을 통하여 동맥과 정맥을 구분하여 영상을 획득한다. 이러한 일반적인 사전포화방법을 응용한 SAAV 기법은 일정영역을 미리 포화(saturation)시킨 후 포화영역의 위, 아래의 영역을 한번에 영상화하여 동맥과 정맥의 구분된 영상을 한번에 획득할 수 있다. 마산 삼성병원의 0.3T MRI system(Megfinder, AILab. Korea)에서 SAAV sequence를 이용하여 정상적인 피험자로부터 목 부위의 동맥과 정맥 혈관영상을 동시에 얻었다. 이들의 각 2D 영상을 Color Mapping으로 조합한 후 Maximum Intensity Projection(MIP) 기법을 통해 3D Artery-Vein Color Mapping(AVCM) MRA 영상으로 재구성하였다. 3명의 피험자에 대한 SAAV MRA data를 256$\times$256$\times$64(resolution： 0.89$\times$0.89$\times$2㎣)로 획득하였다.

• Journal of Chest Surgery
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• v.49 no.5
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• pp.392-396
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• 2016

We report a case of aortic dissection masquerading as acute ischemic stroke followed by intravenous thrombolysis. A 59-year-old man presented with dizziness. After examination, the patient had a seizure with bilateral Babinski signs. Soon after identifying multiple acute infarctions in both hemispheres on diffusion-weighted brain magnetic resonance (MR) imaging, tissue plasminogen activator (t-PA) was administered. Both common carotid arteries were invisible on MR angiography, and subsequent chest computed tomography revealed an aortic dissection. The emergency operation was delayed for 13 hours due to t-PA administration. The patient died of massive bleeding.

• Korean Journal of Radiology
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• v.21 no.12
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• pp.1305-1316
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• 2020

In approximately 10% of patients with acute myocardial infarction (MI), angiography does not reveal an obstructive coronary stenosis. This is known as myocardial infarction with non-obstructive coronary arteries (MINOCA), which has complex and multifactorial causes. However, this term can be confusing and open to dual interpretation, because MINOCA is also used to describe patients with acute myocardial injury caused by ischemia-related myocardial necrosis. Therefore, with regards to this specific context of MINOCA, the generic term for MINOCA should be replaced with troponin-positive with non-obstructive coronary arteries (TpNOCA). The causes of TpNOCA can be subcategorized into epicardial coronary (causes of MINOCA), myocardial, and extracardiac disorders. Cardiac magnetic resonance imaging can confirm MI and differentiate various myocardial causes, while cardiac computed tomography is useful to diagnose the extracardiac causes.

• Investigative Magnetic Resonance Imaging
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• v.7 no.1
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• pp.22-30
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• 2003

Purpose : The efficacy of magnetic resonance imaging for evaluating coronary artery disease has been reported. In this study, we evaluated the usefulness of breath-hold segmented K-space cine MR imaging for evaluating the patency of coronary artery bypass grafts (CABG). Materials and Method s : Thirty eight patients with a total of 92 CABGs (36 internal thoracic arteries and 56 saphenous vein grafts) were evaluated using segmented K-space cardiac-gated fast gradient echo sequence (2D-FASTCARD) MR imaging. MR magnitude images were evaluated from the hard copies by two independent observers. A graft was defined as patent if it was seen as a bright small round area on at least two consecutive images throughout the cardiac cycle at a position consistent with the expected location for that graft. Results : MR images were obtained successfully for 23 patients (61%). The sagittal planes were most helpful in visualizing the cross-section of sapheneous vein bypass graft to left circumflex artery branch, whereas the transverse planes were used for identification of internal mammary artery grafts to left anterior descending coronary artery or its branch and identification of saphenous vein grafts to right coronary artery. Forty five grafts were visible using this MR technique, while the grafts were not visible on seven saphenous vein grafts and two internal mammary artery grafts. In two patients showing symptoms of myocardial ischemia, one or two bypass grafts were not visible. Imaging, perpendicular plane to a CABG was important to visualize the flow inside the CABG with maximum sensitivity. Conclusion : Evaluation of patency of the bypass graft was clinically feasible by 2D-FASTCARD MR imaging, whereas any invisible bypass grafts should be further studied by contrast-enhanced MR angiography or by conventional angiography for confirmation of abnormalities.

• Korean Journal of Digital Imaging in Medicine
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• v.17 no.1
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• pp.43-48
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• 2015

Intracrnial 3D TOF MR angiography was performed in 30 normal volunteers with both 1.5 and 3.0 T MRI system with high resolutions. Used Voxel sizes were $0.39{\times}0.39{\times}0.2$(1.5 T) and $0.19{\times}0.19{\times}0.35$(3.0 T), respectively. High image quality and depiction of small vessel branches were equality demonstrated with 1.5 T and 3.0 T HR TOF MRA(p<0.05). Intracranial high resolution TOF MRA with 1.5 T and 3.0 T provides high diagnostic information with having merits and demerits in depiction of vascular branches.

• Investigative Magnetic Resonance Imaging
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• v.13 no.2
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• pp.137-145
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• 2009

Purpose : To compare 12 and 32-element surface coil arrays for highly accelerated coronary magnetic resonance angiography (MRA) using parallel imaging. Materials and Methods : Steady state free precession coronary MRA was performed in 5 healthy volunteers at 1.5 T whole body MR scanner using both 12 and 32-element surface coil arrays. Left anterior descending and right coronary artery data sets were acquired for each volunteer. Data sets were sub-sampled for parallel imaging using reduction factors from 1 to 6. Mean geometry factor (g-factor), maximum g-factor, and artifact level were calculated for each of the two coil arrays. Results : Over all reduction factors, the mean and maximum g-factors and artifact level were significantly reduced using the 32-element array compared to the 12element array (P << 0.1). The mean g-factor was sensitive to the imaging orientations of coronary arteries while the maximum g-factor and artifact level were independent of orientation. Conclusion : The 32-element surface coil array significantly improves artifact and noise suppression for highly accelerated coronary MRA using parallel imaging. The increased acceleration factors made feasible with the 32-element array offer the potential to enhance spatial resolution or increase volumetric coverage for 3D coronary MRA.

• Journal of Chest Surgery
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• v.41 no.6
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• pp.718-723
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• 2008

Background: The advances in surgical techniques, anesthesia management, perfusion methodology and postoperative intensive care have markedly decreased the mortality and cardiac morbidity of patients who undergo heart surgery over the past 2 decades. Nevertheless, it is well recognized that cardiac surgery carries a substantial risk for central nervous system complications. This study was conducted to evaluate the prevalence of subclinical cerebrovascular lesions in the head and neck by performing magnetic resonance angiography (MRA), and we investigated the clinical course of patients who had abnormal lesion seen on head and neck MRA. Material and Method: The subjects were 107 patients (71 men and 36 women ranging in age from 21 to 83 years) who were scheduled for cardiac surgery under nonemergency conditions between October 2005 and June 2008. Informed consent was obtained before the MRA. The carotid arteries, intracranial arteries and brain parenchyme were examined for subclinical cerebrovascular lesions by performing MRA. We reviewed the patients' medical records and MR findings to evaluate the prevalence of neurologically high risk patients and their clinical course. Result: The overall prevalence of neurologically high risk patients was 15.7% (17 patients). Among these patients, 11 patients had ischemic heart disease and 6 patients had valvular heart disease. Only 2 patients had a history of cerebrovascular disease. The clinical courses of 14 patients (13.1%) were changed according to their MRI findings. Conclusion: The prevalence of subclinical cerebrovascular disease in patients who were scheduled for cardiac surgery was higher than was expected. MR angiography was of value to identify these patients.

• Journal of KIISE:Software and Applications
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• v.30 no.9
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• pp.821-828
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• 2003

The virtual angioscopy was implemented using MR angiography image of carotid artery Inside of the carotid artery is one of the body region not accessible by real optical endoscopy but can be visualized with virtual endoscopy. In order to determine the navigation path, we segmented the common carotid artery and internal carotid artery from the MR angiography image. We used the coordinates as a navigation path for virtual camera that were calculated from medial axis transformation. We used the perspective projection and marching cube algorithm to render the surface from volumetric MRA image data. A stroke occurs when brain cells die because of decreased blood flow to the brain. The carotid artery is the primary blood vessel that supplies the blood flow to the brain. Therefore, the carotid artery stenosis is the primary reason of stroke. The virtual angioscopy is highly recommended as a diagnosis tool with which the specific Place of stenosis can be identified and the degree of stenosis can be measured qualitatively. Also, the virtual angioscopy can be used as an education and training tool for endoscopist and radiologist.