• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.2
• /
• pp.786-792
• /
• 2013

In this study was explored minimize side effects due to the additional injection of contrast medium and maintaining a high resolution imaging applied to the inspection and analysis of the contrast medium that affect the peak time biomechanics factors. Included 48 patients using the test bolus method, after measuring a patient's biomechanics factors of inspection before and during the test, correlation between contrast medium peak time and learn, matches the regression equation calculated and measured contrast medium peak time was assessed by the Bland Altman plot. Research result, inspections of SBP, HR contrast medium peak time and a significant negative correlation was, step 1, every increase, the contrast medium peak time significantly to -0.018 and -0.159 decreased, a fairly high concordance no difference between the two method. In conclusion, the regression equation using the existing methods, while maintaining excellent image quality that contrast medium is reduced to a patient, it can conclude that the alternative to the existing methods.

• Korean Chemical Engineering Research
• /
• v.43 no.1
• /
• pp.85-91
• /
• 2005

$SnO_2$ films were prepared at room temperature under a $(CH_3)_4Sn-H_2-O_2$ atmosphere in order to obtain transparent conductive polymer by using ECR-MOCVD (Electron Cyclotron resonance -Metal Organic Chemical Vapor Deposition) system. The electrical properties of the films were investigated as function of process parameters such as deposition time, microwave power, magnetic current power, magnet/showering/substrate distance and working pressure. An increase in microwave power and magnetic current power brought on $SnO_2$ film formation with low electric resistivity. On the other hand, the effects of process parameters described above on optical properties were insignificant in the range of our experimental scope. The transmittance and reflectance of the films prepared by the ECR-MOCVD exhibited their average values of 93-98% at wave length range of 380-780 nm and 0.1-0.5%, respectively. The grain size of the $SnO_2$ films that are also insensitive with the process parameters were in the range of 20-50 nm. On the basis of experimental data obtained in the present study, electrical resistivity of $7.5{\times}10^{-3}ohm{\cdot}cm$, transmittance of 93%, and reflectance of 0.2% can be taken as optimum values.

• Clinical and Experimental Pediatrics
• /
• v.52 no.7
• /
• pp.804-810
• /
• 2009

Purpose : We investigated whether ictal single-photon emission computed tomography (SPECT) with prolonged injection of technetium-99m (99mTc) ethyl cysteinate dimer during repeated spasms can localize the epileptogenic foci in children with infantile spasms. Methods : Fourteen children with infantile spasms (11 boys, 3 girls; mean age, $2.2{\pm}1.3$ years) were examined. When a cluster of spasms was detected during video electroencephalography (EEG) monitoring, $^{99m}Tc$ ethyl cysteinate dimer was slowly and continuously injected for 2 minutes to determine the presence of ictal SPECT. For 7 children, the ictal and interictal SPECT images were visually analyzed, while for the remaining 7 children, the SPECT images were analyzed using the subtraction ictal SPECT coregistered to magnetic resonance imaging (MRI) (SISCOM) technique. Subsequently, we analyzed the association between the ictal SPECT findings and those of other diagnostic modalities such as EEG, MRI, and positron emission tomography (PET). Results : Increase in cerebral blood flow on ictal SPECT involved the epileptogenic foci in 10 cases6 cases analyzed by visual assessment and 4 analyzed by the SISCOM technique. The ictal SPECT and video-EEG findings showed moderate agreement (Kappa=0.57; 95% confidence interval, 0.18-0.96). Conclusion : Ictal SPECT with prolonged injection of a tracer could provide supplementary information to localize the epileptogenic foci in infantile spasms.

• Journal of the Korean Society of Radiology
• /
• v.3 no.4
• /
• pp.13-21
• /
• 2009

The Magnetic Resonance Imaging (MRI) systems consist of various parameters. Among them, the image quality can be arguably the most important part of the systems. As the other components in MRI systems have been developed and evolved, the MRI image quality has been advanced remarkably. And, the radiation imaging system is being converted from the Film to the digital method, which drives the computerization of many hospitals. The management of the tremendous radiation images becomes more critical. The data compression is used to store such large data in a network server. When the image files are compressed, the image quality degrades comparing to its original images. Even slight quality degradation of a medical image could cause an erroneous diagnosis, so the images must be handled carefully. This thesis studied the image assessment methods of comparing the quality of the compressed image to its original, and the quality of the original and the displayed images of the MRI systems via PSNR with actual medical images used in hospitals. As a result, no noticeable quality degradation was found comparing the compressed images with various digital compression methods and the original images. However, it was a different story comparing the original images and the displayed images on MRI monitors. Some noise or image distortion was visible using any regular CRT or LCD monitors were used while the special monitors designed for the MRI imaging and medical images displayed high definition images.

• Journal of Korean Neurosurgical Society
• /
• v.29 no.10
• /
• pp.1365-1371
• /
• 2000

Objectives : Spinal cord compression is a rare presentation of non-Hodgkin's lymphoma(NHL), occurring in 0.1% to 10.2% of patients. Primary spinal extradural NHL, i.e. occurring in the absence of any detectable extraspinal lymphoproliferative disorder, has a potentially favourable outcome if diagnosed and treated early. The authors describe two patients with a clinical picture of acute spinal cord compression as the first presentation of NHL. Methods : The patients were 48-year-old female and 27-year-old female. Both presented with back pain followed by acute paraparesis and voiding difficulty. One patient was diabetic. Plain radiographs of the spine were not specific. Thoracic spine magnetic resonance imaging(MRI) revealed evidence of extradural soft tissue mass extending multiple vertebral segments. Results : The patients underwent emergency laminectomy for decompression and tissue diagnosis. Histological and immunohistochemical study revealed B-cell lymphoma, intermediate grade in both patients. Postoperative staging did not reveal any additional lesions other than extradural manifestation of the malignant lymphoma. Surgery with additional chemotherapy and radiotherapy allowed the clinical improvement of both patients. Conclusion : The authors report two patients with a clinical picture of acute spinal cord compression as the first presentation of NHL, and stress that primary spinal epidural NHL should be a diagnostic consideration in the patient without prior history of malignancy who presents with a prodrome of back pain followed by a rapid neurological deterioration.

• Clinical and Experimental Pediatrics
• /
• v.46 no.12
• /
• pp.1274-1278
• /
• 2003

Syncope in children and adolescents have a common occurrence according for up to 15% before adulthood. Micturition syncope, a kind of situational syncope, can be considered a form of reflex syncope. It can typically occur in healthy young men after rising from bed in the early morning who experience sudden loss of consciousness during or immediately after urination. The mechanism of micturition syncope is not completely understood, but it has been suggested that vasovagal reflex mediated bradycardia and peripheral vasodilation and decreased venous return due to Valsalva effect and standing position lead to the decrease in cerebral blood flow resulting in syncope. The causes of syncope are variable. So complete history taking, physical examination, electrocardiography, exercise stress test, echocardiography, head-up tilt table test, electroencephalography(EEG), brain magnetic resonance image and urodynamic study should be required for the diagnosis of micturition syncope. There were several reports about micturition syncope. However, literature of micturition syncope at the pediatric age has rarely been reported in Korea so far. Therefore, we report a case of a 9-year-old boy with micturition syncope with typical EEG findings of high amplitude delta wave and flattening during syncope.

• Clinical and Experimental Pediatrics
• /
• v.55 no.2
• /
• pp.63-67
• /
• 2012

A 4-year-old girl with Panayiotopoulos syndrome presented with a history of 4 prolonged autonomic seizures. The clinical features of her seizures included, in order of occurrence, blank staring, pallor, vomiting, hemi-clonic movement on the right side, and unresponsiveness. A brain magnetic resonance imaging (MRI) showed a slightly high $T_2$ signal in the left hippocampus. Interictal electoencephalogram revealed spikes in the occipital area of the left hemisphere. We analyzed the current-source distribution of the spikes to examine the relationship between the current source and the high $T_2$ signal. The current source of the occipital spikes was not only distributed in the occipital area of both cerebral hemispheres, but also extended to the posterior temporal area of the left hemisphere. These findings suggest that the left temporal lobe may be one of the hyperexcitable areas and form part of the epileptogenic area in this patient. We hypothesized that the high $T_2$ signal in the left hippocampus of our patient may not have been an incidental lesion, but instead may be related to the underlying electroclinical diagnosis of Panayiotopoulos syndrome, and particularly seizure. This notion is important because an abnormal $T_2$ signal in the hippocampus may represent an acute stage of hippocampal injury, although there is no previous report of hippocampal pathology in Panayiotopoulos syndrome. Therefore, long-term observation and serial follow-up MRIs may be needed to confirm the clinical significance of the $T_2$ signal change in the hippocampus of this patient.

• Journal of Korean Neurosurgical Society
• /
• v.30 no.3
• /
• pp.395-399
• /
• 2001

Primary spinal epidural lymphoma(SEL), i.e. occurring in the absence of any detectable extraspinal lymphoproliferative disorder, is an unusual cause of spinal cord compression. The authors report a 48-year-old, diabetic woman presented with back pain followed by acute paraparesis and voiding difficulty. She had been treated with acupunctures on her back before admission, and complete blood count showed leukocytosis with neutrophilia and increased erythrocyte sedimentation rate(ESR). Thoracic spine magnetic resonance imaging(MRI) revealed an epidural mass extending from T5 to T8 with compression of the spinal cord. Emergency decompressive laminectomy was performed with a tentative diagnosis of spinal epidural abscess, but a B-cell lymphoma was final pathologic diagnosis. Further staging showed no other sites of lymphoma, and the spinal lesion was treated by chemotherapy and radiotherapy. The authors stress that primary SEL can mimic spinal epidural abscess(SEA) in the diabetic patient and should be a diagnostic consideration in patients with a syndrome of acute spinal cord compression manifested by a prodrome of back pain and neuroimaging consistent with an epidural compressive lesion, especially in a diabetic.

• Journal of the Korean Magnetics Society
• /
• v.10 no.3
• /
• pp.123-132
• /
• 2000

Cerium substituted YIG thin films were grown by rf magnetron sputter techniques. We investigated the effects of post-deposition heat-treatment as well as various deposition parameters such as substrate materials, substrate temperature. sputter power, and sputter gas types on the crystallinity, chemical composition, microstructure and magnetic characteristics of the films. Post-deposition heat treatment over 750 $\^{C}$ was applied to crystallize as-prepared amorphous films, and a strong tendency of particular crystallographic planes tying parallel to substrate surface was observed for the post-deposition heat-treated films on GGG substrate. The chemical composition of the films exhibited a wide range of chemical stoichiometry depending on the oxygen fraction of sputter gas, and in particular the composition of the film deposited in sputter gas with an oxygen fraction of R = 10% was Ce$\_$0.23/Y$\_$1.30/Fe$\_$3.50/O$\_$12/. With raising the temperature of post-deposition heat-treatment from 900 $\^{C}$ to 1100 $\^{C}$, the surface roughness of the film on GGG substrates increased from about 3 nm to 40 nm, but their coercive force and ferromagnetic resonance line width decreased from 0.477 kA/m to 0.369 kA/m and from 12.5 kA/m to 8.36 kA/m, respectively.

• Progress in Medical Physics
• /
• v.9 no.1
• /
• pp.1-9
• /
• 1998

In order to provide complementary image data, CT(computed tomography), MR(magnetic resonance) and angiography have been used in the field of Stereotactic Radiosurgery(SRS) and neurosurgery. The aim of this work is to develop 3-D stereotactic localization system in order to determine the precise shape, size and location of the lesion in the brain in the field of Stereotactic Radiosurgery(SRS) and neurosurgery using multi-image modality and multi purpose QA phantom. In order to obtain accurate position of a target, Hitchcoke stereotactic frame and CT/angiography localizers were rigidly attached to the phantom with nine targets dispersed in 3-D space. The algorithms to obtain a 3-D stereotactic coordinates of the target have been developed using the images of the geometrical phantom which were taken by CT/angiography. Positions of targets computed by our algorithms were compared to the absolute position assigned in the phantom. Outlines of targets on each CT image were superimposed each other on angiography images. A spatial mean distance errors were 1.02${\pm}$0.17mm for CT with a 512${\times}$512 matrix and 2mm slice thickness, 0.41${\pm}$0.05mm for angiogra- phy localization. The resulting accuracy in the target localization suggests that the developed system has enough Qualification for Stereotactic Radiosurgery (SRS).