• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.11
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• pp.2077-2082
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• 2008

Recent the advanced technologies in medical imaging such as magnetic resonance imaging (MRI) and computed tomography (CT) make doctors improve the diagnostic skill with detailed anatomical information. In general, it is necessary to get a number of MRI images in order to obtain more detail information. However, the performance of MRI machines of privately run hospitals is not good and thus we may obtain only a few of MRI images. If 3D surface reconstruction is accomplished with a few slices, then it generates 3D surface of poor qualify. This paper propose a way to Set a 3D surface of high quality from a few of number of slices. First of all, our algorithm detects the boundary of tissues which we want to reconstruct as a 3D object and find out the set of vortices on the boundary. And then we generate a 3D implicit surface to interpolate the boundary points by using radial basis function. Lastly, we render the 3D implicit surface by using Marching cube algorithms.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.424-427
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• 2008

MRI 기계의 성능에 따라서 사용되는 슬라이스의 수가 적을 수 있다. 결과적으로 적은 슬라이스를 이용해 3D surface를 재구성하게 되면 퀄리티가 낮아지는 문제가 발생한다. 본 논문에서는 적은 수의 슬라이스를 이용하여 높은 퀄리티의 3D surface를 얻는 방법을 제안한다. 이를 위한 알고리즘은 먼저 원하는 영역의 경계를 찾아서 그 경계선들의 점을 찾는다. 이러한 점들을 이용하여 Radial Basis Function을 이용해서 슬라이스와 슬라이스 사이를 보간하고 이렇게 보간된 데이터들을 이용하여 Marching cube 알고리즘을 이용하여 렌더링 한다.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.4
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• pp.203-207
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• 2013

The appropriate handling of motion artifacts is essential for clinical diagnosis in magnetic resonance imaging (MRI). In many cases, motion is an inherent part of MR images because it is difficult to control during MR imaging. As the motion in the human body occur in a deformable manner, they are difficult to deal with. This paper proposes a novel detection method for periodically moving regions to produce MR images with less motion artifacts. When the data is acquired by the radial trajectory, the proposed method can extract the deformable region easily using the difference in the modulated sinograms, which have different periodic phase terms. The simulation results applied to the various cases confirmed the good performance of the proposed method.

• Korean Journal of Radiology
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• v.22 no.5
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• pp.829-839
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• 2021

Objective: To compare the diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3-tesla (3T) magnetic resonance imaging (MRI) and computed tomography (CT) for the detection of visceral pleural surface invasion (VPSI). Visceral pleural invasion by non-small-cell lung cancer (NSCLC) can be classified into two types: PL1 (without VPSI), invasion of the elastic layer of the visceral pleura without reaching the visceral pleural surface, and PL2 (with VPSI), full invasion of the visceral pleura. Materials and Methods: Thirty-three patients with pathologically confirmed VPSI by NSCLC were retrospectively reviewed. Multidetector CT and contrast-enhanced 3T MRI with a free-breathing radial three-dimensional fat-suppressed volumetric interpolated breath-hold examination (VIBE) pulse sequence were compared in terms of the length of contact, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. Supplemental evaluation of the tumor-pleura interface (smooth versus irregular) could only be performed with MRI (not discernible on CT). Results: At the tumor-pleura interface, radial VIBE MRI revealed a smooth margin in 20 of 21 patients without VPSI and an irregular margin in 10 of 12 patients with VPSI, yielding an accuracy, sensitivity, specificity, positive predictive value, negative predictive value, and F-score for VPSI detection of 91%, 83%, 95%, 91%, 91%, and 87%, respectively. The McNemar test and receiver operating characteristics curve analysis revealed no significant differences between the diagnostic accuracies of CT and MRI for evaluating the contact length, angle of mass margin, or arch distance-to-maximum tumor diameter ratio as predictors of VPSI. Conclusion: The diagnostic performance of contrast-enhanced radial T1-weighted gradient-echo 3T MRI and CT were equal in terms of the contact length, angle of mass margin, and arch distance-to-maximum tumor diameter ratio. The advantage of MRI is its clear depiction of the tumor-pleura interface margin, facilitating VPSI detection.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.19-19
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• 2003

목적： MRI 시스템에서 얻어지는 기초 Data는 K-space 즉 촬영대상의 Fourier Transform 된 Data 이다. 이 K-space Data는 영상 촬영 기법에 따라 다른 형식으로 얻어지게 되는데, 이 연구에서는 Radial Imaging에서 Repetition Time 과 Echo Time을 줄이기 위해 구현된 영상기법을 이용하여 얻어진 Data를 이용하여 영상을 재구성하는 방법을 제시하고자 한다.

• Journal of the Korean Society of Radiology
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• v.85 no.2
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• pp.345-362
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• 2024

MRI plays an important role in abdominal imaging because of its ability to detect and characterize focal lesions. However, MRI examinations have several challenges, such as comparatively long scan times and motion management through breath-holding maneuvers. Techniques for reducing scan time with acceptable image quality, such as parallel imaging, compressed sensing, and cutting-edge deep learning techniques, have been developed to enable problem-solving strategies. Additionally, free-breathing techniques for dynamic contrast-enhanced imaging, such as extra-dimensional-volumetric interpolated breath-hold examination, golden-angle radial sparse parallel, and liver acceleration volume acquisition Star, can help patients with severe dyspnea or those under sedation to undergo abdominal MRI. We aimed to present various advanced abdominal MRI techniques for reducing the scan time while maintaining image quality and free-breathing techniques for dynamic imaging and illustrate cases using the techniques mentioned above. A review of these advanced techniques can assist in the appropriate interpretation of sequences.

• Journal of Trauma and Injury
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• v.28 no.1
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• pp.21-26
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• 2015

Complete radial tears of the lateral meniscus are relatively rare. Once torn, the injury can be debilitating due to disruption of the circumferential fibers of the meniscus. We experienced a case of a lateral meniscus with a complete radial tear at the midbody, where the two torn ends were displaced more than 1 cm and could not be approximated during arthroscopy. Thirteen months after surgery, follow-up MRI and second-look arthroscopic findings showed that the complete radial tear has healed spontaneously. However, twenty nine months after the second-look arthroscopy, the patient complained of severe knee pain during exercise. On follow-up MRI, increased sclerosis and newly developed bone marrow edema were observed in the lateral femoral condyle, compared with previous MR images. Finally, we performed meniscal allograft transplantation due to the defective properties of the completely healed lateral meniscus.

• Proceedings of the KSMRM Conference
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• 2003.10a
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• pp.18-18
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• 2003

목적： MRI 시스템에서 얻어지는 Data는 TR(Repetition Time)과 TE(Echo Time)에 따라서 신호 대잡음비(SNR), 조직들간의 대조도(Contrast), Artifact 및 촬영시간이 결정된다. 이 연구에서는 TR/TE를 줄이는 기법을 이용한 Radial Imaging 영상기법을 제시하고자 한다. 대상 및 방법： 일반적인 Radial Imaging 기법에 HASTE 기법과 Non-uniform sampling 기법의 특징을 이용하여 구현하였으며, TR/TE를 줄일 수 있었으며 얻어진 K-space Data는 가변주파수 역 Fourier Transform을 이용하여 Projection Data를 재구성한 후 Back Projection 기법을 이용하여 최종 영상을 재구성한다.

• Journal of the Korean Arthroscopy Society
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• v.17 no.1
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• pp.6-10
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• 2013

Purpose: This study intends to verify the usefulness of magnetic resonance imaging (MRI) for estimate recovery after arthroscopic pull-out repair at root tears of medial meniscus. Materials and Methods: We performed 17 patients who examined MRI and arthroscopy among patients who had received repair of medial meniscus from November, 2007 to June, 2011. To determine restoration meniscus, we performed arthroscopy and MRI. Results: Lysholm knee scores before and after operation were average 56.4 and 79.0 and visual analogue scale (VAS) score was improved from 8 points to 3 points. From secondary look arthroscopy performed after operation, 17 cases showed stabilization after regeneration. However, In MRI, cleft sign implying root tears of medial meniscus was observed in all cases before and after operation, ghost sign was observed in 10 cases and 9 cases respectively, radial linear defect was showed 17 cases and 15 cases respectively. Conclusion: It was not useful that MRI after medial meniscus repair in non-anatomical site, to consider restoration of medial meniscus. To evaluate for recovery medial meniscus after repair more exactly, secondary arthroscopy would be required.

• Journal of KIISE:Software and Applications
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• v.36 no.10
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• pp.825-835
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• 2009

The advance in medical technology has decreased death rates from diseases such as tubercle, pneumonia, malnutrition, and hepatitis. However, death rates from cardiac diseases are still increasing. To prevent cardiac diseases and quantify cardiac function, magnetic resonance imaging not harmful to the body is used for calculating blood volumes and ejection fraction(EF) on routine clinics. In this paper, automatic left ventricle(LV) segmentation is presented to segment LV and calculate blood volume and EF, which can replace labor intensive and time consuming manual contouring. Radial threshold determination is designed to segment LV and blood volume and EF are calculated. Especially, basal slices which were difficult to segment in previous researches are segmented automatically almost without user intervention. On short axis cardiac MRI of 36 subjects, the presented algorithm is compared with manual contouring and General Electronic MASS software. The results show that the presented algorithm performs in similar to the manual contouring and outperforms the MASS software in accuracy.