• Korean Journal of Clinical Laboratory Science
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• v.37 no.2
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• pp.123-128
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• 2005

Magnetoencephalography (MEG) is the measurement of the magnetic fields produced by electrical activity in the brain, usually conducted externally, using extremely sensitive devices such as Superconducting Quantum Interference Device (SQUID). MEG needs complex and expensive measurement settings. Because the magnetic signals emitted by the brain are on the order of a few femtoteslas (1 fT = 10-15T), shielding from external magnetic signals, including the Earth's magnetic field, is necessary. An appropriate magnetically shielded room is very expensive, and constitutes the bulk of the expense of an MEG system. MEG is a relatively new technique that promises good spatial resolution and extremely high temporal resolution, thus complementing other brain activity measurement techniques such as electroencephalography (EEG), positron emission tomography (PET), single-photon emission computed tomography (SPECT) and functional magnetic resonance imaging (fMRI). MEG combines functional information from magnetic field recordings with structural information from MRI. The clinical uses of MEG are in detecting and localizing epileptic form spiking activity in patients with epilepsy, and in localizing eloquent cortex for surgical planning in patients with brain tumors. Magnetoencephalography may be used alone or together with electroencephalography, for the measurement of spontaneous or evoked activity, and for research or clinical purposes.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.3
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• pp.81-86
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• 2015

We fabricated a 3D knee joint model through the imaging processing. The 3D shape information is different depends on specific conditions when the shape of real knee joint is extracted from CT/MRI sliced images. The two types of joint models were fabricated by using 3D printer in order to analysis of joint movement by slight difference of 3D shape information. The compressive force experiments were performed by using knee joint model. As the results, the compressive forces were changed with respect to the difference of geometry. Consequently, feasibility test should be performed before developing biomimetic bioreactor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.05d
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• pp.33-37
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• 2003

Endovaginal and endorectal receiver only surface coil were designed for MR imaging(MRI) and $^1H$ MR spectroscopy(MRS) for the uterine cervix and the prostate. The shape of endovaginal coil wire was rectangular with round comer. The shape of endorectal coil wire was long elliptic shape during insertion and circular shape after insertion. Conventional spin echo and fast spin echo sequences were used as T1 and T2 weighted imaging sequences, respectively. 3D volume localized in vivo $^1H$ MR spectroscopy of the human cervix and prostate was performed using PRESS or STEAM localization method. Using home-built endvaginal and endorectal coils, excellent T1 and T2 images were obtained to visualize early cervical and prostate tumors. 3D volume localized in vivo $^1H$ MRS was useful to differentiate the cancerous tissue from the normal tissue.

• Journal of Korean Foot and Ankle Society
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• v.11 no.1
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• pp.18-22
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• 2007

Purpose: To provide basic data on anatomy of the ankle joint in adults using magnetic resonance imaging as well as to compare measurements with available data of corresponding dimension in the different sizes of the total ankle replacements design ($HINTEGRA^{(R)}$). Materials and Methods: Magnetic resonance (MR) sagittal and coronal images from one hundred-forty nine were studied. Post traumatic, arthritic, or grossly deformed ankles at any reason were excluded. Lengths, widths of the main parts of this articulation and also the radius of curvature of talar dome were measured in the MR images. Statistical analysis was performed on these measurements. Results: On MR coronal image data, average tibial width was $30.0{\pm}4.1\;mm$ and talar width was $27.0{\pm}3.4\;mm$. On sagittal image date, average anteroposterior length of the distal tibia was $39.0{\pm}4.2\;mm$, average anteroposterior length of the talus was $31.3{\pm}2.8\;mm$, and average sagittal radius of curvature of talar dome was $20.1{\pm}2.9\;mm$. All measurements in male were significantly larger than in female (p<0.01), but a significant difference according to age was not found. Conclusion: Ankle morphometric data define a basis of size, particularly useful in the design of ankle prostheses.

• Imaging Science in Dentistry
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• v.30 no.1
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• pp.87-91
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• 2000

Lymphangiomas are uncommon benign congenital tumors. Most occur in the head and neck and most lesions present by the age of 2 years. We present our experience with four patients who have lymphangiomas of the head and neck with tongue involvement. First case is a 7-year-old male who has the cystic lymphangioma of left submandibular area. Second a 22-year-old female has a lesion involving the border of right tongue. Third case is the lymphangioma which occurs in the right upper lip of a 6-year old male. The last patient is a 28-year old male who fell down and whose right face was swollen up. He had undergone an operation and been treated with steroid before. The characteristic appearances of imaging methods were described and all lesions best depicted on T2-weighted images. Our experience indicates that MRI is useful in the diagnosis and treatment planning of lymphangioma.

• Imaging Science in Dentistry
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• v.50 no.1
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• pp.73-79
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• 2020

Computed tomography (CT) and magnetic resonance imaging (MRI) can be useful for the evaluation of palatal lesions, and strain elastography (performed together with intraoral ultrasonography) is a relatively new sonographic imaging modality. This report describes 2 clinical cases in which strain elastography was used to assess palatal tumors in conjunction with intraoral ultrasonography, CT, and MRI. In the first case, diagnosed as a myoepithelioma, the strain was determined to be 0.000% (strain of normal tissue, 0.556%). In the second case, diagnosed as an adenoid cystic carcinoma, the determined strain was 0.000% (strain of normal tissue, 1.077%). Therefore, we conclude that intraoral strain elastography can be useful for evaluating palatal lesions.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.7
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• pp.945-949
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• 2014

In cardiac magnetic resonance imaging (CMRI), heart and respiratory motions are one of main obstacles in obtaining diagnostic quality of images. To synchronize CMRI to the physiological motions, ECG and respiratory gatings are commonly used. In this paper multi-biological signal (ECG, respiratory, and SPO2) based smart trigger system is proposed. By using multi-biological signal, the proposed system is robust to the induced noise such as eddy current when gradient pulsing is continuously applied during the examination. Digital conversion of the multi-biological signal makes the system flexible in implementing smart and intelligent algorithm to detect cardiac and respiratory motion and to reject arrhythmia of the heart. The digital data is used for real-time trigger, as well as signal display, and data storage which may be used for retrospective signal processing.

• Journal of Biosystems Engineering
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• v.28 no.2
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• pp.157-166
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• 2003

The purpose of this study is to characterize the internal physical properties of fresh Korean ginsengs (Panax ginseng C.A. Meyer) through a magnetic resonance imaging (MRI) technique. Current external visual inspection cannot determine internal quality of ginsengs successfully. Relaxation time constants, T$_1$ and T$_2$*, were obtained from a series of MR images. Calculated Ti values were varied with different physiological states of ginseng tissues. Internal imaging information was obtained nondestructively from fresh ginsengs. One- and two-dimensional image analyses were performed. One-dimensional image analysis showed a potential of age identification of ginsengs rapidly. Internal quality of normal and abnormal ginsengs was evaluated using two-dimensional MR images. Various types of internal defects such as internal cavity and rotten spot were visualized clearly. The MRI technique had a feasibility to detect internal defects of fresh ginsengs effectively.

• Journal of Korean Orthopaedic Sports Medicine
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• v.10 no.2
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• pp.124-128
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• 2011

Many types of meniscal anomalies have been reported. The authors encountered one case of anomalous insertion of the anterior horn of the medial meniscus to the anterior horn of the lateral meniscus, which ran up along the course of the transverse ligament. This anomalous band was detected in MRI of the knee as a horizontal tear of anterior horn of the lateral meniscus but found during the operation as a anomalous insertion of the anterior horn of the medial meniscus. We report the case with a review of the literature.

• Proceedings of the KOSOMBE Conference
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• v.1992 no.05
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• pp.85-91
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• 1992

In MRI, an image contrast can be developed as a result of the susceptibility effect if an object has paramagnetic substances. This is mainly due to the non-uniform phase distribution or linear gradient developed by the magnetic susceptibility within a voxel, which in turn reduces the signal intensity; e.g., spin phases are dephased and thereby cancel each other resulting in a reduced signal. In this paper, a new concept for manipulating the susceptibility effect through the use of tailored RF pulses is proposed. As potential applications of the method, two different types of tailored RF pulses are introduced: one for susceptibility artifact correction and the other for contrast enhancement. The latter, for example, can be applied to angiography utilizing the paramagnetic property of deoxygenated blood. Both a theoretical study of the method and experimental results are reported.