• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.66-74
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• 1997

fMRI, functional MRI introduced receently appears based on the gradient echo technique which is sensitive to the field inhomogeneity developed due to the local susceptibility changes of blood oxygenation and deoxygenation. There has been many variants of the basic gradient echo sequence which is sensitive to the local inhomogeniety, among others such as GRASS or SSFP to EPISTAR are the most commonly used gradient echo techniques. Common to all these gradient echo techniques is that the signal due to the susceptibility effects is generally decreased with increasing inhomogeneity due to the $T2^{*}$ effect or conventionally konwn as blood oxygenation level dependent(BOLD) effect. It is, also found that the BOLD sensitivity is also dependent on the imaging modes, namely whether the imaging is in axial, or coronal or sagittal mode as well as the directions of the vessels against the main magnetic field. We have, therefore, launched a systematic study of imaging mode dependent signal change or BOLD sensitivity as well as the signal changes due tothe tilting angle of the imaging planes. Study has been made for both TRFGE sequence and CGE sequence to compare the distinctions of the each mode since each technique has different sensitivity againsst susceptibility effect. Method of computation and both the computer simulations and their corresponding experimental results are presented.

• Journal of radiological science and technology
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• v.20 no.1
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• pp.29-34
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• 1997

For radiological test in soft tissue or neighboring part with same signal intensity, proper test method and equipment shall be selected as needed. In case of female pelvic cavity, ultrasonography or computed tomography alternatively used, but MRI can be more usefully applied to design treatment method or operation plan by improving the diagnostic accuracy and careful observation of lesion characteristics. Magnetic Resonance Imaging using recently developed Enteral MRI contrast media can acquire more diagnostic information than using only intravenous contrast media. Thus this study attempted to examine the utility of anatomic structure and diagnostic acquisition by imaging the female pelvic cavity using Enteral MRI contrast media. As a result of analyzing magnetic resonance Imaging after administering Enteral MRI contrast media to pelvic cavity suspect patients, more diagnostic information media could be acquired than only using Intravenous contrast. Expecially, in the diagnosis of lesion position, shape, distinction from neighboring tissues it is thought that external Enteral MRI contrast media should be used.

• Korean Journal of Radiology
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• v.20 no.4
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• pp.533-541
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• 2019

Breast magnetic resonance imaging (MRI) has been increasingly utilized, especially in screening for high-risk cases, because of its high sensitivity and superior ability to detect cancers as compared with mammography and ultrasound. Several limitations such as higher cost, longer examination time, longer interpretation time, and low availability have hindered the wider application of MRI, especially for screening of average-risk women. To overcome some of these limitations and increase access to MRI screening, an abbreviated breast MRI protocol has been introduced. Abbreviated breast MRI is becoming popular and challenges the status quo. This review aims to present an overview of abbreviated MRI, discuss the current findings, and introduce ongoing prospective trials.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.123-129
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• 2011

Purpose : To compare lumbar disc changes between initial lumbar spine (L-spine) MRI and follow-up (f/u) MRI that were performed due to recurred backaches. Materials and Methods : A total 50 patients who had undergone f/u L-spine MRI were retrospectively reviewed. Five discs (L1-S1) were surveyed in each f/u MRI. Lumbar disc changes were defined as no change, aggravations, or improvements compared to initial disc states. These states were defined on the basis of morphologic status and disc levels. Results : In a total of 250 discs in 50 patients, 31 discs (12.4%) showed morphologic changes of disc lesions, whereas 219 discs (87.6 %) showed no changes. Among the 31 disc lesions, 24 were aggravated and 7 were partially improved. And on the basis of disc status, initially abnormal discs revealed any morphologic changes of the degree of disc herniation. A total of 33.3% of the morphologic changes are noted in initially extruded discs. Fifteen morphologic changes of disc lesions were located at the L4-5 level. Conclusion : Our results suggest that correlations between lumbar disc herniations and back pain symptoms are limited, and that evaluations of extra disc lesions are required.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.628-634
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• 2018

In an examination of the temporomandibular joint disc, MRI(Magnetic Resonance Imaging) is a useful method, and it is necessary to conduct an examination with one's mouth open for a long time to observe the accurate position change of the disc. Thus, this study would produce a TMJ device, using the 3-D printing technology, which would maintain the state of opening the mouth and would evaluate its usefulness as compared to the existing fixed device. As compared to the image using the existing TMJ device, the image taken with the self-produced TMJ device with a 3-D printer showed a somewhat lower SNR, but there was no defect for a clinical use. It is judged that benefits to costs would increase, since it can be customized for the individual patient and can contribute to the production of similar tools by utilizing the 3-D printing technology.

• Journal of radiological science and technology
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• v.27 no.3
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• pp.19-24
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• 2004

MRI imaging is one of the imaging techniques showing anatomical structures of human body for medical diagnosis, and has been researched in order to provide better quality of anatomical information. In this study, we propose a very useful method to extract an interest areas and how to diagnose necrolysis of femoral neck disease automatically. Regions of femoral neck is set using anatomical features and Hough transform and advantages of both region extension and histogram-based region segmentation method are combined for better region segmentation. As a result of the proposed method, good imaging quality was obtained for femoral neck with both normal and severe necrosis as well as for femoral neck in early stage of necrolysis.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.10a
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• pp.83-85
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• 2017

Generally, the current organ projection systems are the MRI and the CT. The MRI and the CT, (MRI) allow the surgeon to see the internal organs without incising the human body. However, since the images generated by the machines are 2D, it is difficult for doctors to observe the internal organs in three dimension. In this paper, we develop the augmented projection system for internal organs by using the augmented reality technology. The developed system shows the internal organs of the body using a holographic lens as a stereoscopic image and allows for doctors to examine the internal organs in detail.

• Journal of radiological science and technology
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• v.44 no.1
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• pp.31-37
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• 2021

This study aim of quantitative assessment of Noise Power Spectrum(NPS) and image characteristics of by acquired the optimal image for noise characteristics and quality assurance by using magnetic resonance imaging(MRI). MRI device was (MAGNETOM Vida 3.0T MRI; Siemense healthcare system; Germany) used and the head/neck shim MR receive coil were 20 channels coil and a diameter 200 mm hemisphere phantom. Frequency signal could be acquired the K-space trajectory image and white image for NPS. The T2 image highest quantitatively value for NPS finding of showed the best value of 0.026 based on the T2 frequency of 1.0 mm-1. The NPS acquired of showed that the T1 CE turbo image was 0.077, the T1 CE Conca2 turbo image was 0.056, T1 turbo image was 0.061, and the T1 Conca2 turbo image was 0.066. The assessment of NPS image characteristics of this study were to that could be used efficiently of the MRI and to present the quantitative evaluation methods and image noise characteristics of 3.0T MRI.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.425-427
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• 2022

The grade of glioma is important information related to survival and thus is important to classify the grade of glioma before treatment to evaluate tumor progression and treatment planning. Glioma grading is mostly divided into high-grade glioma (HGG) and low-grade glioma (LGG). In this study, image preprocessing techniques are applied to analyze magnetic resonance imaging (MRI) using the deep neural network model. Classification performance of the deep neural network model is evaluated. The highest-performance EfficientNet-B6 model shows results of accuracy 0.9046, sensitivity 0.9570, specificity 0.7976, AUC 0.8702, and F1-Score 0.8152 in 5-fold cross-validation.

• Investigative Magnetic Resonance Imaging
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• v.16 no.2
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• pp.189-194
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• 2012

We report a case of cardiac lymphoma in a 40-year-old man, who had a mediastinal mass which was diagnosed as sclerosing mediastinitis pathologically. The mediastinal mass caused right pulmonary arterial stenosis. The patient developed myocardial hypertrophy and echocardiography showed restrictive physiology and severely decreased left ventricle ejection fraction, 6 months later. MRI showed global left ventricular myocardial hypertrophy and diffuse late gadolinium hyperenhancement after administration of contrast material. Thus, non-ischemic cardiomyopathy was suspected on MRI. However, pathology confirmed the myocardial abnormality as lymphoma after myocardial biopsy. Because a basal part of the left ventricle and global subendocardial myocardium were not involved on contrast-enhanced delayed MRI, the MRI abnormalities could be differentiated from amyloidosis and other myocardial diseases. The peculiar non-mass forming diffuse hypertrophy pattern of cardiac lymphoma has not been known in the MRI literature.