• Journal of the Korean Society of Radiology
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• v.81 no.3
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• pp.676-687
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• 2020

Purpose To analyze the altered brain regions and intrinsic brain activity patterns in trauma-exposed firefighters without posttraumatic stress disorder (PTSD). Materials and Methods Resting-state functional MRI (rsfMRI) was performed for all subjects. Thirty-one firefighters over 40 years of age without PTSD (31 men; mean age, 49.8 ± 4.7 years) were included. Twenty-six non-traumatized healthy controls (HCs) (26 men; mean age, 65.3 ± 7.84 years) were also included. Voxel-based morphometry was performed to investigate focal differences in the brain anatomy. Seed-based functional connectivity analysis was performed to investigate differences in spontaneous brain characteristics. Results The mean z-scores of the Seoul Verbal Learning Test for immediate and delayed recall, Controlled Oral Word Association Test (COWAT) score for animals, and COWAT phonemic fluency were significantly lower in the firefighter group than in the HCs, indicating decreased neurocognitive function. Compared to HCs, firefighters showed reduced gray matter volume in the left superior parietal gyrus and left inferior temporal gyrus. Further, in contrast to HCs, firefighters showed alterations in rsfMRI values in multiple regions, including the fusiform gyrus and cerebellum. Conclusion Structural and resting-state functional abnormalities in the brain may be useful imaging biomarkers for identifying alterations in trauma-exposed firefighters without PTSD.

• Investigative Magnetic Resonance Imaging
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• v.3 no.2
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• pp.188-195
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• 1999

The fMRI signals are composed of many various signals. It is very difficult to find the accurate parameter for the model of fMRI signal containing only neural activity, though we may estimating the signal patterns by the modeling of several signal components. Besides the nose by the physiologic motion, the motion of object and noise of MR instruments make it more difficult to analyze signals of fMRI. Therefore, it is not easy to select an accurate reference data that can accurately reflect neural activity, and the method of an analysis of various signal patterns containing the information of neural activity is an issue of the post-processing methods for fMRI. In the present study, fMRI data was analyzed with the Independent Component Analysis(ICA) method that doesn't need a priori-knowledge or reference data. ICA can be more effective over the analytic method using cross-correlation analysis and can separate the signal patterns of the signals with delayed response or motion related components. The Principal component Analysis (PCA) threshold, wavelet spatial filtering and analysis of a part of whole images can be used for the reduction of the freedom of data before ICA analysis, and these preceding analyses may be useful for a more effective analysis. As a result, ICA method will be effective for the degree of freedom of the data.

• Journal of Korean Neurosurgical Society
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• v.30 no.1
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• pp.41-46
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• 2001

Objective : The exact position of the lesion during the pallidotomy is critical to obtain the clinical improvement of parkinson's disease without damage to surrounding structure. Ventriculogrphy, CT(computed tomograpy) or MRI(magnetic resonance imaging) have been used to determine the initial coordinates of stereotactic target for pallidotomy. The goal of this study was to determine whether microelectrode recording significantly improves the neurophysiologic localization of the target obtained from MRI. Methods : Twenty patients were studied. They underwent a unilateral pallidotomy. Leksell frame was applied and T1 axial images parallel to the AC-PC(anterior commissure-posterior commissure) plane using a 1.5 Tesla MRI with 3mm slice thickness were obtained. Anteroposterior coordinate of target was chosen at 2mm in front of the midcommissural point and lateral coordinate between 19 and 22mm from the midline. The vertical coordinate was calculated on coronal slice using a fast spin echo inversion recovery sequence(FSEIR) related to the position of the choroidal fissure and ranged over 4-5mm below the AC-PC plane. Confirmation of the anatomical target was done on axial slices using the same FSEIR sequence . Microrecording was done at the pallidum contralateral to the symptomatic side using an electrode with a tip diameter of $1{{\mu}m}$ diameter tip and 1.1-1.4 mOhm impedance at 1000Hz. Electrophysiologic localization of the target was also confirmed intraoperatively by macrostimulation. Results : Microrecording techniques were reliable to define the transition from the base of the pallidum which was characterized by the disappearance of spike activity and by the change of the audible background activity. Signals from high amplitude neurons firing at 200-400Hz were recorded in the pallidal base. X, Y and Z coordinates of target obtained from the MRI were within 1mm from the X, Y, Z coordinates obtained with microrecording in 16 patients (80%), 15 patients(75%), 10 patients(50%) respectively. The difference of Y coordinate between on MRI and on microrecording was 4mm in only one patient. Conclusion : The MRI was accurate to localize the target within 1mm of the error from microrecording target in 70% of the patients. 4mm discrepancy was observed only once. We conclude that MRI alone can be used to determine the target for pallidotomy in most patients. However, microrecording technique can still be extremely valuable in patents with aberrant anatomy or unusual MRI coordinates. We also consider physiologic confirmation of the target using macrostimulation to be mandatory in all cases.

• Journal of the Korean Society of Radiology
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• v.14 no.2
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• pp.111-120
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• 2020

Research should be actively conducted for the ability of X-ray equipment and Retrospective image analysis of X-ray equipment used in hospitals. Retrospective image analysis of X-ray machines, CT and MRI of radiology and medical equipment has been actively conducted. However, image quality measurement using angiography equipment of angiography room is mostly measured with phantom, and image quality measurement on image after being taken by actual patient is insufficient and researches on accurate image quality measurement method are remarkable. It is in short supply. Therefore, through this study, the researcher devised a method to measure the image quality of the acquired image after coronary angiography, and to provide a high quality image to the operator. The equipment and programs used were angiographic examination equipment (Axiom Artis Zee Ceiling) and Image J program. Subjects were images automatically saved in PACS program after coronary angiography.For image quality measurement, selected the AP Caudal 30° image that show the LCA vessel well and the LAO 30° image that show the RCA vessel well during the coronary angiography. In order to measure the background and ROI of the selected image by selecting an image, a criterion on how to find and measure a section where the overlap of the shadow, such as blood vessel, liver and lung is minimized, is presented. In conclusion, there is no exact standard for analyzing an image quality measurement method of angiography image. Therefore, in order to provide quality images to the practistioners, not only the technicians of the equipment but also the users who actually use them should become researchers and conduct research on image quality measurement in various ways. Thus, it is expected to provide excellent images to patients.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.267-269
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• 2010

3D 모니터의 공급으로 IT영역 및 의료영상 분야 에서도 3D 영상에 관한 산업 발달이 화두가 되고 있다. 의료영상은 CT, MRI 영상의 정확한 판독이 필요하기 때에 2D 의료영상보다 구체적인 3D 정보를 얻을 수 있는 3D 입체영상에 관심이 높아지고 있다. 본 논문에서는 3D 의료 촬영기계가 아닌 기존의 2D 의료 평면 영상 한 장만을 이용한 3D 입체영상을 제작하는 방법을 제안한다. 실험 영상으로 CT의 2D 의료영상을 사용한다. 장기의 영역 분할을 한후, 각 장기 성분을 분석한다. 분리 한 장기들은 명암값에 의해 구분 되며, 이를 바탕으로 영상의 깊이 정보를 추출한다. 추출한 정보로 깊이맵을 작성한다. 작성된 깊이 맵과 기본 2D 의료영상과 합성, 깊이를 할당하여 3D영상을 구현한다.

• The Academic Congress of Korean Shoulder and Elbow Society
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• 2005.03a
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• pp.14-15
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• 2005

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.163-164
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• 2015

본 연구에서는 영상의학과에서 시행하는 검사 중 MRI검사실에서 근무하는 방사선사들의 감염에 대한 인식을 조사하고, 가장 많이 사용하고 있는 키보드와 마우스에 대한 감염관리 실태를 파악함으로써, 작업종사자의 감염관리의 중요성 및 교육의 필요성을 제시하고자 한다.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.183-186
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• 1995

• Proceedings of the KSMRM Conference
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• 1999.04a
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• pp.43-54
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• 1999

Protocol이란 Dorland의 의학사전에 의하면 "어떤 술기의 절차에 대한 명백하고 상세한 계획서(an explicit detailed plan of a procedure)"로 정의된다. 그래서 liver MR imaging protocol은 간에 발생한 병적 문제를 해결하기 위해서, 자기공명영상술을 실시하는 구체적이고 세부적인 지침서를 말하게 된다. 그러나 현실적으로 병원에 따라 imaging protocol은 조금씩 다르다. 왜냐하면 MR장비가 다르고, 적절한 펄스파형(pulse sequence)에 대한 통일된 안이 없기 때문이다. 자기공명영상술은 지금도 계속해서 빠르게 발전하고 있기 때문에, 현재 통용되는 영상 술기에 대한 자세한 지침은 곧 소용이 없게 된다. 그래서 본 소고에서는 간의 MR 영상화와 병변의 특성화에 대한 기본 적인 면에 더욱 중점을 두고 기술하고자 한다. 기술하고자 한다.

• Proceedings of the KSMRM Conference
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• 1999.04a
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• pp.81-86
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• 1999

MR은 높은 조직 대조도와 축상, 시상 및 관상면 등의 multiplanar capability의 커다란 장점을 갖고 있어 뇌 신경계질환 진단에 필수적이며, 특히 ionizing radiation이 아니고 요오드계 IV 조영제를 사용하지 않는다는 점이 CT에 비해 더욱 유리하다. 소아에서의 뇌신경계 질환은 선천성 기형이나 대사성 질환이 많은 등 성인과는 다른 질환분포를 보인다. 따라서 성인에서와 같은 protocol을 그대로 적용하였을 때 좋은 질의 영상을 얻기 힘든 경우가 있으며, 연령 또는 질환에 따라 촬영기법도 다양하게 하여야 하므로 routine protocol을 정하지 않고 매 환아 마다 적절한 기법을 선택하고 있다. 또한 움직임을 억제하기 위하여 진정 (sedation)이 필요한 예가 대부분이며 적절한 잠재우기는 좋은 질의 영상을 얻기 위해 필수적이므로 이에 대한 지식을 필요로 한다.