• Biomedical Science Letters
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• v.11 no.1
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• pp.31-36
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• 2005

To evaluate the magnetic resonance imaging and electron microscopic findings of the hyperacute stage of cerebral fat embolism in cats and the time needed for the development of vasogenic edema. Magnetic resonance imaging was performed at 30 minutes (group 1, n=9) and at 30 minutes and 1, 2, 4, and 6 hours after embolization with triolein (group 2, n= 10). As a control for group 2, the same acquisition was obtained after embolization with polyvinyl alcohol particles (group 3, n=5). Electron microscopic examination was done in all cats. In group 1, the lesions were iso- or slightly hyperintense on T2-weighted (T2W) and diffusion-weighted (DWIs) images, hypointense on the apparent diffusion coefficient (ADC) map image, and markedly enhanced on the gadolinium-enhanced T1-weighted images (Gd-T1WIs). In group 2 at 30 minutes, the lesions were similar to those in group 1. Thereafter, the lesions became more hyperintense on T2WIs and DWIs and more hypoinfense on the ADC map image. In group 3, the lesions showed mild hyperintensity on T2WIs at 6 hours but hypointensity on the ADC map image from 30 minutes, with a tendency toward a greater decrease over time. Electron microscopic findings revealed discontinuity of the capillary endothelial wall, perivascular and interstitial edema, and swelling of glial and neuronal cells in groups 1 and 2. The lesions were hyperintense on T2WIs and DWIs, hypointense on the ADC map image, and enhanced on Gd-T1WIs. On electron microscopy, the lesions showed cytotoxic and vasogenic edema with disruption of the blood-brain barrier.

• Investigative Magnetic Resonance Imaging
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• v.4 no.2
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• pp.128-135
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• 2000

Purpose : The aim of this study is to develope the Magnetic Resonance Spectroscopy(MRS) data processing S/W which plays an important role as a diagnostic tool in clinical field. Materials and methods : Post-processing software of MRS based on graphical user interface(GUI) under windows operating system of personal computer(PC) was developed using MATLAB(Mathwork, U.S.A.). This tool contains many functions to increase the quality of spectrum data such as DC correction, zero filling, line broadening, Gauss-Lorentzian filtering, phase correction, etc. And we obtained the normal human brain $^1H$ MRS data from parietal white matter, basal ganglia and occipital grey matter region using 1.5T Gyroscan ACS-NT R6 (philips, Amsterdam, Netherland) MRS package. The analysis of the MRS peaks were performed by obtaining the ratio of peak area. Results : The peak ratios of NAA/Cr, Cho/Cr, MI/Cr for the different MRS machines have a little different values. But these peak ratios were not significantly different between different echo time MRS peak ratios in the same machine (p<0.05). Conclusion : MRS post-processing S/W based on GUI using PC was developed and applied to the analysis of normal human brain $^1H$ MRS. This independent MRS processing job increases the performance and throughput of patient scan of main console. Finally, we suggest that the database for normal in-yivo human MRS data should be obtained before clinical applications.

• Progress in Medical Physics
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• v.12 no.2
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• pp.113-124
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• 2001

For veterinary imaging diagnosis, we obtained MR images of the canine brain, spine, kidney and pelvis from 3T MRI system which was equipped with the world first 3T active shield magnet. Spin echo (SE) and fast Spin Echo (FSE) images were obtained from the canine brain, spine, kidney and pelvis of normal and sick dogs using a homemade birdcage and transverse electromagnetic (TEM) resonators operating in quadrature and tuned to 128 MHz. In addition, we employed a homemade saddle shaped RF coil. Typical common acquisition parameters were as follows: matrix=512$\times$512, field of view (FOV)=20cm, slice thickness=3 w, number of excitations (NEX)=1. For T1-weighted MR images, we used TR=500 ms, TE=10 or 17.4 ms. For T2-weighted MR images, we used TR=4000 ms, TE=108 ms. Signal to noise ratio (SNR) of 3T system was measured 2.7 times greater than that of prevalent 1.57 system. The high resolution images acquired in this study represent more than a 4-fold increase in in-plane resolution relative to conventional images obtained with a 20 cm field of view and a 5 mm slice thickness. MR images obtained from 3T system revealed numerous small venous structures throughout the image plane and provided reasonable delineation between gray and white matter The present results demonstrate that the MR images from 3T system could provide better diagnostic quality of resolution and sensitivity than those of 1.5T system. The elevated SNR observed in the 3T high field magnetic resonance imaging can be utilized to acquire images with a level of resolution approaching the microscopic structural level under in vivo conditions. These images represent a significant advance in our ability to examine small anatomical features with noninvasive imaging methods. Moreover, MRI technique could begin to apply for veterinary medicine in Korea.

• Journal of Korean Neurosurgical Society
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• v.59 no.5
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• pp.466-470
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• 2016

Objective : To determine imaging features that may separate adamantinomatous and papillary variants of craniopharyngiomas given that tumors with adamantinomatous signature features are associated with higher recurrence rates, morbidity, and mortality. We specifically reviewed calcification on CT, T1 bright signal intensity, and cystic change on T2 weighted images for differentiating these two types. Methods : We retrospectively reviewed the MRI and CT studies in 38 consecutive patients with pathologically proven craniopharyngiomas between January 2004 and February 2014 for the presence of calcification on CT scans, bright signal intensity on T1 weighted images, and cystic change on T2 weighted images. Results : Of the 38 craniopharyngiomas, 30 were adamantinomatous type and 8 were papillary type. On CT scans, calcification was present in 25 of 38 tumors. All calcified tumors were adamantinomatous type. Twenty four of 38 tumors had bright signal intensity on T1 weighted images. Of these 24 tumors, 22 (91.7%) were adamantinomatous and 2 were papillary type. Cystic change on T2 weighted images was noted in 37 of 38 tumors; only 1 tumor with papillary type did not show cystic change. Conclusion : T1 bright signal intensity and calcification on CT scans uniformly favor the adamantinomatous type over papillary type of craniopharyngioma in children. However, these findings are more variable in adults where calcification and T1 bright signal intensity occur in 70.6% and 58.8% respectively of adult adamantinomatous types of craniopharyngiomas.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.8-16
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• 2007

Finite element analysis (FEA) is an effective means for the analysis of bioelectromagnetism. It has been successfully applied to various problems over conventional methods such as boundary element analysis and finite difference analysis. However, its utilization has been limited due to the overwhelming computational load despite of its analytical power. We have previously developed a novel mesh generation scheme that produces FE meshes that are content-adaptive to given MR images. MRI content-adaptive FE meshes (cMeshes) represent the electrically conducting domain more effectively with far less number of nodes and elements, thus lessen the computational load. In general, the cMesh generation is affected by the quality of feature maps derived from MRI. In this study, we have tested various feature maps created based on the improved differential geometry measures for more effective cMesh head models. As performance indices, correlation coefficient (CC), root mean squared error (RMSE), relative error (RE), and the quality of cMesh triangle elements are used. The results show that there is a significant variation according to the characteristics of specific feature maps on cMesh generation, and offer additional choices of feature maps to yield more effective and efficient generation of cMeshes. We believe that cMeshes with specific and improved feature map generation schemes should be useful in the FEA of bioelectromagnetic problems.

• Journal of Oriental Neuropsychiatry
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• v.12 no.1
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• pp.219-229
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• 2001

The brainstem include midbrain, pons & medulla. In acute stage of brainstem infarction, neurologic symptoms may be progressive. So we must pay special attention to Wallenberg's syndrome. In other words, Wallenberg's syndrome is dorsolateral medullary syndrome. A-54-years-old woman was admitted because of vertigo, ataxia & somatic sensory loss of left face and right half-body. Brain MRI showed high SI in T2W, low SI in T1W lesion left medullary infarction. We diagnosed the case as Shin-heo type Oriental medically and prescribed Gihwangemjakamibang. Diabetes mellitus was found out. So We have controlled diabetes mellitus by Occidental medical therapy. In the end, The symptoms of the patient became better. We know that cooperative(oriental & occidental) medical therapy is better than one medical therapy.Here we present one case of Wallenberg's syndrome who was admitted at Kunpo Wonkwang University Hospital Oriental Neuropsychiatry from 14th March to 6th April. 2001.

• Clinical and Experimental Pediatrics
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• v.46 no.1
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• pp.95-99
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• 2003

Krabbe disease is a rare autosomal recessive disorder clinically characterized by retardation in motor development, prominent spasticity, seizures, and optic atrophy. Pathologically, there are many globoid cells in the white matter, in addition to the lack of myelin and the presence of severe gliosis. Hence Krabbe disease is known as globoid cell leukodystrophy. Biochemically, the primary enzymatic deficiency in Krabbe disease is galactocerebroside beta-galactosidase. Patients with Krabbe disease can be subdivided into the early-onset type and late-onset type, according to the onset of clinical manifestations. Most patients with early-onset type die before their second birthday. We describe a girl with Krabbe disease associated with uncontrolled seizures, which was confirmed with biochemical study and MRI. The clinical findings of this patient included hyperirritability, scissoring of the legs, flexion of arm, and clenching of the fists, and generalized tonic seizures. EEG showed hypsarrhythmia, and MRI demonstrated degenerative white matter changes in bilateral periventricular white matter, posterior rim of internal capsule, basal ganglia and brain stem on T2W1 and FLAIR image. The diagnosis was based on clinical features of progressive neurologic deterioration in conjunction with low galactocerebroside beta-galactosidase activity.

• Journal of Veterinary Clinics
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• v.32 no.5
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• pp.464-468
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• 2015

A 6-year-old, intact male maltese was presented with hindlimb ataxia of 4 day duration. Physical and neurological examinations revealed a bright, alert, and responsive dog, with no evidence of cranial nerve deficits, conscious proprioceptive deficits. Spinal reflexes of the hind and forelimbs were normal. Patellar, cranial tibial, and withdrawal reflexes were normal. Pain could not be elicited on manipulation of the neck or palpation of the spinal column. Survey radiographs of the vertebral column were unremarkable. Computed tomography (CT) scans in the transverse plane were performed. The results of CT imaging were unremarkable. Magnetic resonance imaging (MRI) in both sagittal and transverse planes was performed. The extent of the lesion was 25 mm in length by 4 mm in thickness. The spinal cord was deviated ventrally and appreared thinner. On T1-weighted and FLAIR images, a discrete hypointense lesion dorsal to the spinal cord was observed at L1-2 which was contiguous with the subarachnoid space. On T2-weighted images, this region was hyperintense, consistent with a fluid-filled structure. The signal intensity of the cysts was equivalent to cerebrospinal fluid (CSF). Surgical treatment involving dorsal laminectomy had successful outcomes.

• Journal of the Korean Society of Radiology
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• v.2 no.2
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• pp.31-38
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• 2008

Line scan diffusion weighted imaging (LSDI) pulse sequence for 0.32 T magnetic resonance imaging (MRI) system was developed. In the LSDI pulse sequence, the imaging volume is formed by the intersection of the two perpendicular planes selected by the two slice-selective $\pi$/2-pulse and $\pi$-pulse and two diffusion sensitizing gradients placed on the both side of the refocusing $\pi$-pulse and the standard frequency encoding readout was followed. Since the maximum gradient amplitude for the MR system was 15 mT/m the maximum b value was $301.50s/mm^2$. Using the developed LSDI pulse sequence, the diffusion weighted images for the aqueous NaCl solution phantom and triacylglycerol solution phantom calculated from the line scan diffusion weighted images gives the same results within the standard error range (mean diffusivities = $963.90{\pm}79.83({\times}10^{-6}mm^2/s)$ at 0.32 T, $956.77{\pm}4.12({\times}10^{-6}mm^2/s)$ at 1.5 T) and the LSDI images were insensitive to the magnetic susceptibility difference and chemical shift.

• Journal of Oriental Neuropsychiatry
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• v.15 no.1
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• pp.211-217
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• 2004

Chronic acquired hepatocerebral degeneration(CAHD) is a heterogenous that can occur with a primary neurologic, hepatic, or combined presentation. Symptoms and signs of that included progressive dementia, dysarthria, involuntary movements(including tremor, asterixis, and choreoathetosis), ataxia of limb and gait, typically in a patient with chronic liver cirrhosis. Characteristic radiologic findings is high signal on globus pallidus on T1W1 MRI. Recently, we experienced a patients, a 73-year-old female with CAHD presenting mental change, cognitive deficits, and various involuntary movement. In our patient, T1 weighted MRI of the brain showed symmetric high signal intensity in both basal ganglia. Increased ammonia $level(226{\mu}g/dl)$ in whole blood and a multiple anomalous vessels with spleno-renal shunt on abdominal CT were found. But, liver cirrhosis is absent. In admission care, these mental change and involuntary movements had a good response to herbal medication. We report on patient with CAHD which had a spontaneous spleno-renal shunt without liver disease.