• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.336-339
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• 2012

VTK is a free but professional development platform for images three-dimensional (3D) reconstruction and processing. It is powerful, open-source, and users can customize their own needs by self-development of great flexibility. To give the doctors more and detailed information by simulate dissection to the 3-D brain MRI image after reconstruction. A Visualization System (VS) is proposed to achieve 3D brain reconstruction and virtual dissection functions. Based on the free VTK visualization development platform and Visual Studio 2010 IDE development tools, through C++ language, using real people's MRI brain dataset, we realized the images 3D reconstruction and also its applications and extensions correspondingly. The display effect of the reconstructed 3D image is well and intuitive. With the related operations such as measurement, virtual dissection and so on, the good results we desired could be achieved.

• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.213-217
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• 2015

To report problems found in a patient who has implemented stent implantation and then conducted a perfusion MRI using ASL(Arterial Spin Labeling), in order to suggest a solution to them. The perfusion MRI was conducted, using pCASL among ASL methods. Data from pCASL(Pseudo Continuous Arterial Spin Labeling) was acquired together with the structural image simply by changing position(labeling gap 15 mm, 170 mm) of the labeling pulse to avoid stent. Data was processed through the ASLtbx. When perfusion MRI was acquired using pCASL, it showed that the position of the conventional labeling pulse (labeling gap 24 mm) was overlapped with that of stent, which made signal intensity in right brain tissue appear as if it were void. When the labeling pulse was positioned (labeling gap 15 mm) to avoid stent, high signal intensity images were acquired. In labeling pulse (labeling gap 170 mm), the signal intensity was more reduced due to relaxation before labeled blood arrived at the imaging slice. pCASL can be stably repeated measurements because it does not use a contrast agent. And it should be selected with the appropriate image acquisition parameters for the high quality image.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.239-244
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• 2018

Both arterial dissection and atherosclerosis are major causes of cerebral infarction and appear to be occlusion or stenosis in magnetic resonance angiography(MRA) and computed tomographic angiography(CTA). But there are differences in treatment because they have different mechanisms. Recently, as high resolution magnetic resonance image(HR-MRI) develops, the image of blood vessel wall can be confirmed non-invasively. Though HR-MRI has become a very useful method for patients with suspected arterial dissection, differential diagnosis of the two diseases has not yet been fully established due to differences in the findings according to stages of arterial dissection and atherosclerosis. We investigated the differences between vertebral artery dissection and atherosclerosis through HR-MRI in two patients and confirmed the diagnosis by CTA follow-up. In addition to the previously established diagnostic criteria, we determined that the long and severe stenosis and recanalization suggest arterial dissection. Characteristics of arterial dissection confirmed by HR-MR and additional studies will be helpful for the treatment.

• Investigative Magnetic Resonance Imaging
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• v.19 no.4
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• pp.224-230
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• 2015

Purpose: To determine whether we should recommend ultrasonography (US) for an incidental thyroid nodule identified by additional cervicothoracic sagittal T2-weighted image (C-T sag T2WI) of lumbar spine magnetic resonance imaging (MRI). Materials and Methods: A retrospective study of 61 patients who underwent both lumbar spine MRI and thyroid US between December 2011 and April 2015 was conducted. For all US-found thyroid nodules > 1 cm, investigators evaluated whether there was any correlation between thyroid nodule detectability by C-T sag T2WI and US features such as echogenicity, composition, or suspicion of malignancy. Results: Solid hypoechoic (2/4; 50%) or mixed echoic nodules (4/8; 50%) appeared to be found relatively more easily by C-T sag T2WI than more benign-looking solid isoechoic (1/4; 25%) or spongiform nodules (0/6; 0%). Among six nodules with ultrasonographic suspicion for malignancy, only one nodule was detected by C-T sag T2WI. Conclusion: If an incidental thyroid nodule is seen by C-T sag T2WI, it would be better to recommend thyroid US for identifying malignancy.

• Journal of Korea Multimedia Society
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• v.15 no.9
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• pp.1075-1085
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• 2012

In clinical research using medical images, the image segmentation is one of the most important processes. Especially, the hippocampal atrophy is helpful for the clinical Alzheimer diagnosis as a specific marker of the progress of Alzheimer. In order to measure hippocampus volume exactly, segmentation of the hippocampus is essential. However, the hippocampus has some features like relatively low contrast, low signal-to-noise ratio, discreted boundary in MRI images, and these features make it difficult to segment hippocampus. To solve this problem, firstly, We selected region of interest from an experiment image, subtracted a original image from the negative image of the original image, enhanced contrast, and applied anisotropic diffusion filtering and gaussian filtering as preprocessing. Finally, We performed an image segmentation using two level set methods. Through a variety of approaches for the validation of proposed hippocampus segmentation method, We confirmed that our proposed method improved the rate and accuracy of the segmentation. Consequently, the proposed method is suitable for segmentation of the area which has similar features with the hippocampus. We believe that our method has great potential if successfully combined with other research findings.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.40 no.3
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• pp.181-188
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• 2003

In this paper, we introduce a magnetic noise shielding method to reduce the noise effects in permanent magnet based MRI systems. Through FEM electromagnetic analyses, we have shown that the magnetic noise component parallel to the main magnetic field is the major component that makes various artifacts in the images obtained with a permanent magnet based MRI. Based on the FEM analyses, we have developed an active magnetic noise shielding system composed of a magnetic field sensor, compensation coils, and a coil driving system. The shielding system has shown a noise rejection ratio of about 30dB at the frequency below several Hz. We have experimentally verified that the shielding system greatly improves the image quality in a 0.3 Tesla MRI system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.4
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• pp.582-591
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• 2000

In this paper, the Finite-Difference Time-Domain(FDTD) modeling method of the Korean human head is introduced to calculate electromagnetic energy absorption for the human head by mobile phones. After MRI scanning data is obtained, 2 dimensional(2D) segmentation is done from the 2D MRI image data by the semi-automatic method. Then, 3D dense segmentation data with $1mm\times1mm\times1mm$ is constructed from the 2D segmentation data. Using the 3D segmentation data, coarse FDTD models of human head that is tilted arbitrarily to model the condition of tilted usage of mobile phone.

• Imaging Science in Dentistry
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• v.33 no.2
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• pp.63-70
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• 2003

Purpose: To describe the MRI findings of the retrodiskal tissue in patients presenting with TMJ internal derangement and to correlate these findings with clinical and other MRI manifestations. Materials and Methods: One hundred eighteen joints of 63 patients with TMJ internal derangement were examined by MRI. Tl-weighted sagittal MR images taken in both closed- and open-mouth were evaluated for the presence of demarcation between disk and retrodiskal tissue, the presence of low signal intensity, and the depiction of the temporal part of the posterior attachment. The results were correlated with the duration of TMJ internal derangement, the presence of pain, and other MRI findings, including the type of internal derangement, the extent of disk displacement, the degree of disc deformation, and the presence of osteoarthrosis. Results: A significant relationship between the presence of low signal intensity in the retrodiskal tissue and other MRI findings was determined. Low signal intensity on the open-mouth view was observed more frequently in patients with disc displacement without reduction, severe disc displacement and deformation, and osteoarthrosis (p<0.05). The demarcation between disk and retrodiskal tissue, and the depiction of the temporal part of the posterior attachment(TPA) were correlated neither with clinical, nor with other MRI findings. Conclusion: This study suggests that low signal intensity in the retrodiskal tissue on open-mouth MR image can be indicative of advanced stages of disk displacement.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.7
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• pp.487-494
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• 2013

Medical image watermarking has received extensive attention as wide security services in the healthcare information system. This paper proposes a blind medical image watermarking approach on the segmented gray-matter (GM) images by utilizing discrete wavelet transform (DWT) and discrete cosine transform (DCT) along with enhanced suppressed fuzzy C-means (EnSFCM) for the optimal selection of sub-blocks position to insert a watermark. Experimental results show that the proposed approach outperforms other methods in terms of peak signal to noise ratio (PSNR) and M-SVD. In addition, the proposed approach shows better robustness than other methods in normalized correlation (NC) values against several attacks, such as noise addition, filtering, JPEG compression, blurring, histogram equalization, and cropping.

• The Journal of the Korea Contents Association
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• v.5 no.3
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• pp.45-51
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• 2005

This paper emphasizes on the accomplishment of compensated proton density image and T2 weighted image taken from the shrinkage surface of the Brain. From the images, the Brain's surface shrinkage in the normal image and the surface shrinkage in the abnormal image can be observed. After the separation of white matter, gray matter, and CSF, this algorithm calculates the volume of each of them automatically. Results are subdivided into particular ages and saved in the database to be analyzed and to be processed statistically. Therefore, by using this algorithm the normal and abnormal stages can be detected in the early stages to diagnose. This result easily discernment Alzheimer patient and is useful for Alzheimer diagnostic and early detection.