• Investigative Magnetic Resonance Imaging
• /
• 제23권3호
• /
• pp.270-275
• /
• 2019

This study presents a case of diffuse large B cell lymphoma (DLBCL) in a 58-year-old man showing unusual manifestations mimicking chronic osteomyelitis. In this case review, we describe the imaging findings of DLBCL which mimics chronic osteomyelitis and review existing reports regarding the differential diagnosis of bone involvement of lymphoma and osteomyelitis through imaging and laboratory findings and diffusion-weighted magnetic resonance imaging (DWI) such as the advanced MRI sequence.

• 한국자기공명학회논문지
• /
• 제23권2호
• /
• pp.40-45
• /
• 2019

The phase transition temperatures and thermodynamic properties of $(NH_4)_2MnCl_4{\cdot}2H_2O$ grown by the slow evaporation method were studied using differential scanning calorimetry and thermogravimetric analysis. A structural phase transition occurred at temperature $T_{C1}$ (=264 K), whereas the changes at $T_{C2}$ (=460 K) and $T_{C3}$ (=475 K) seemed to be chemical changes caused by thermal decomposition. In addition, the chemical shift and the spin-lattice relaxation time $T_{1{\rho}}$ were investigated using $^1H$ magic-angle spinning nuclear magnetic resonance (MAS NMR), in order to understand the role of $NH_4{^+}$ and $H_2O$. The rise in $T_{1{\rho}}$ with temperature was related to variations in the symmetry of the surrounding $H_2O$ and $NH_4{^+}$.

• Investigative Magnetic Resonance Imaging
• /
• 제25권4호
• /
• pp.209-217
• /
• 2021

Magnetic resonance angiography (MRA) plays an important role in accurate diagnosis and appropriate treatment planning for patients with arterial disease. Contrast-enhanced (CE) MRA is fast and robust, offering hemodynamic information of arterial flow, but involves the risk of a side effect called nephrogenic systemic fibrosis. Various non-contrast-enhanced (NCE) MRA techniques have been developed by utilizing the fact that arterial blood is moving fast compared to background tissues. NCE MRA is completely free of any safety issues, but has different drawbacks for various approaches. This review article describes basic principles of CE and NCE MRA techniques with a focus on how to generate angiographic image contrast from a pulse sequence perspective. Advantages, pitfalls, and key applications are also discussed for each MRA method.

• Investigative Magnetic Resonance Imaging
• /
• 제25권4호
• /
• pp.281-292
• /
• 2021

Cranial-nerve disorders can be caused by a wide spectrum of diseases, including congenital, inflammatory, and tumorous diseases, and are often encountered in practice. However, the imaging of cranial-nerve disorders is challenging, and understanding the anatomical differences of each region is essential for conducting the best protocols and for detecting subtle changes in cranial nerves during magnetic resonance imaging (MRI) examinations. In this review we discuss which MRI techniques are best for observing normal and pathologic appearance, according to the different regions of the cranial nerves.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제27권5호
• /
• pp.488-491
• /
• 2005

A 3-year-old female, 5kg, Shih-tzu developed an acute onset of depression, disorientation, hypersalivation, nystagmus after falling down 2 meter height place. In plain skull radiography, there was fracture line in the frontal and parietal bones and next day magnetic resonance imaging examination was performed. Magnetic resonance imaging of the brain was performed with 3.0 Tesla unit. Under general anesthesia, the dog was placed in prone with its head positioned in a birdcage coil. Transverse, sagittal and coronal fast spin echo images of the brain were obtained with the following pulse sequences: T1 weighted images (TR = 560 ms and TE = 18.6 ms) and T2 weighted images (TR = 3500 ms and TE = 80 ms). Magnetic resonance imaging showed epidural hematoma in the left frontal area resulting in compression of the adjacent brain parenchyma. Left lateral ventricle was compressed secondarily and the longitudinal fissure shifted to the right, representing mass effect. The lesion was iso-to slightly hyperintense on T1 weighted image and iso-slightly hypointense signal on T2 weighted image. At necropsy, there was a skull fracture and epidural hematoma in the left frontal area. Magnetic resonance imaging of epidural hematoma is reviewed.

• Transactions on Electrical and Electronic Materials
• /
• 제6권4호
• /
• pp.159-163
• /
• 2005

We analyzed the fault current limiting characteristics of a flux-lock type $high-T_c$ super­conducting fault current limiter (HTSC-FCL) using series resonance between capacitor for series resonance and magnetic field coil which was installed in coil 3. The capacitor for the series resonance in the flux-lock type HTSC-FCL was inserted in series with the magnetic field coil to apply enough magnetic field into HTSC element, which resulted in higher resistance of HTSC element. However, the impedance of the flux lock type HTSC-FCL has started to decrease since the current of coil 3 exceeded one of coil 2 after a fault accident. The decrease in the impedance of the FCL causes the line current to increase and, if continues, the capacitor for the series resonance to be destructed. To avoid this operation, the flux-lock type HTSC-FCL requires an additional device such as fault current interrupter or control circuit for magnetic field. From the experimental results, we investigated the parameter range where the operation as mentioned above for the designed flux-lock type HTSC-FCL using series resonance occurred.

• 한국자기공명학회:학술대회논문집
• /
• 한국자기공명학회 2002년도 제20회 학술발표회
• /
• pp.18-18
• /
• 2002

• 한국자기공명학회논문지
• /
• 제7권2호
• /
• pp.80-88
• /
• 2003

We have performed $^{11}$ B nuclear magnetic resonance (NMR) measurements to microscopically investigate an electronic structure of the ferromagnetic state in three different compositions of calcium-hexaboride single crystals. Although the crystal structure of Ca $B_{6}$ is cubic and three NMR lines may be expected for the nuclear spin 3/2 of $_{11}$ B, a larger number of NMR resonance peaks have been observed. The frequency and intensity of those peaks distinctively changes depending on the angle between crystalline axis and magnetic field. Analyzing this behavior, we find that the electric field gradient(EFG) tensor at the boron has its principal axis perpendicular to the six cubic faces with a quadrupole resonance frequency $v_{Q}$ 600 kHz. Even though the magnetization data highlight the ferromagnetic hysteresis, $^{11}$ B NMR linewidth data show no clear microscopic evidence of the ferromagnetic state in three different compositions of Ca $B_{6}$ single crystals.s.

• 한국자기공명학회논문지
• /
• 제22권2호
• /
• pp.34-39
• /
• 2018

The Nuclear Magnetic Resonance (NMR) technique using Dynamic Nuclear Polarization (DNP) procedures is one of the promising techniques that enable overcoming low sensitivity problems in NMR spectroscopy. We constructed an ODNP-NMR system using a commercial benchtop EPR spectrometer. The $^1H$ NMR peak area of water in aqueous solutions of 4-hydroxy-TEMPO was enhanced more than 95 times in the ODNP-NMR experiments. Our signal enhancement results were about 55% of the previously reported result. This could be due to non-uniform microwave power over a sample and unwanted sample heating by microwave. However, this portable ODNP-NMR spectrometer will be eventually useful for site-specific detection with nano-scale spatial resolutions and molecular dynamics studies with significantly improved signal sensitivity.

• 한국자기공명학회논문지
• /
• 제20권4호
• /
• pp.109-113
• /
• 2016

Resonance frequencies from the $^{113}Cd$ and $^{133}Cs$ nuclear magnetic resonance (NMR) spectra for the $CsCdBr_3$ single crystal were measured at varying temperatures by the static NMR method. The temperature-dependent changes of these frequencies are related to the changing structural geometry of the ${CdBr_6}^{4-}$ units, which affects the environment of $^{133}Cs$. The spin-lattice relaxation rates ($1/T_1$) for the $^{113}Cd$ and $^{133}Cs$ nuclei were measured in order to obtain detailed information about the dynamics of $CsCdBr_3$ crystals. The dominant relaxation mechanisms for $^{113}Cd$ and $^{133}Cs$ nuclei are direct single-phonon and Raman spin-phonon processes, respectively.