• Progress in Medical Physics
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• v.18 no.1
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• pp.1-6
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• 2007

A system to non-invasively fix and monitor eye by a head mounted display (HMD) with a CCD camera for stereotactic radiotherapy (SRS) of uveal melanoma has been developed and implemented clinically. The eye fixing and monitoring system consists of a HMD showing patient a screen for fixing eyeball, a CCD camera monitoring patient's eyeball, and an immobilization mask. At flrst, patient's head was immobilized with a mask. Then, patient was Instructed to wear HMD, to which CCD camera was attached, on the mask and see the given reference point on its screen. While patient stared at the given point in order to fix eyeball, the camera monitored Its motion. Four volunteers and one patient of uveal melanoma for SRS came into this study. For the volunteers, setup errors and the motion of eyeball were analyzed. For the patient, CT scans were peformed, with patient's wearing HMD and fixing the eye to the given point. To treat patient under the same condition, daily CT scans were also peformed before every treatment and the motion of lens was compared to the planning CT Setup errors for four volunteers were within 1mm and the motion of eyeball was fixed within the clinically acceptable ranges. For the patient with uveal melanoma, the motion of lens was fixed within 2mm from daily CT scans. An eye fixing and monitoring system allowed Immobilizing patient as well as monitoring eyeball and was successfully implemented in the treatment of uveal melanoma for SRS.

• Journal of Korean Neurosurgical Society
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• v.63 no.5
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• pp.614-622
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• 2020

Objective : The method of approach during transforaminal endoscopic lumbar discectomy (TELD) has been the subject of repeated study. However, the ideal entry point during TELD has not been studied in detail. Therefore, this study investigated the ideal entry point for avoiding complications using computed tomography (CT) scans obtained from patients in the prone position. Methods : Using CT scans obtained from patients in the prone position, we checked for retroperitoneal or visceral violations and measured the angles of approach with five conventional approach lines drawn on axial CT scans at each disc space level (L2-3, L3-4, and L4-5). We also determined the ideal entry point distance and approach angles for avoiding retroperitoneal or visceral violations. Correlation analysis was performed to identify the patient characteristics related to the ideal entry point properties. Results : We found that the far lateral approach at the L2-3 level resulted in high rates of visceral violation. However, rates of visceral violation at the L3-4 and L4-5 levels were remarkably low or absent. The ideal angles of approach decreased moving caudally along the spine, and the ideal entry point distances increased moving caudally along the spine. Weight, body mass index (BMI), and the depth of the posterior vertebral line from the skin were positively associated with the distance of the ideal entry point from the midline. Conclusion : We reviewed the risk of the extreme lateral approach by analyzing rates of retroperitoneal and visceral violations during well-known methods of approach. We suggested an ideal entry point at each level of the lumbar spine and found a positive correlation between the distance of the entry point to the midline and patient characteristics such as BMI, weight, and the depth of the posterior vertebral line from the skin.

• Journal of Korean Neurosurgical Society
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• v.51 no.4
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• pp.215-218
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• 2012

Objective: Traumatic epidural hematomas (EDHs) in children are a relatively unusual occurrence. The cause and outcome vary depending on period and reg ion of study. The aims of this analysis were to review the cause and outcome of pediatric EDHs nowadays and to discuss outcome-related variables in a large consecutive series of surgically treated EDH in children. Methods: This is a retrospective review of 29 patients with surgically treated EDHs between Jan 2000 and February 2010. Patients' medical records, computed tomographic (Cl) scans, and, if performed, magnetic resonance imaging (MRI) were reviewed to define variables associated with outcome. Variables included in the analysis were age, associated severe intracranial injury, abnormal pupillary response, hematoma thickness, severity of head injury (Glasgow Coma Scale score), parenchymal brain injury, and diffuse axonal injury. Results: The mean (SO) age of the patients was 109 months (0-185 months). Most of the injuries with EDHs occurred in traffic accident (14 cases, 48.2%) and followed by slip down in 6 cases and falls in 6 cases. There were one birth injury and one unknown cause. EDHs in traffic accidents occurred in pedestrians hit by a motor vehicle, 9 cases; motorbike and car accidents, 5 cases and bicycle accidents, 1 case. The locations of hematoma were almost same in both sides (left side in 15 cases). Temporal lobe is the most common site of hematomas (13 cases, 44%). The mean size of the EDHs was 18 mm (range, 5-40 mm). Heterogeneous hematomas in CT scans were 20 cases (67%). Two patients were referred with unilateral or bilateral dilated pupil(s). There was enlargement of EDH in 5 patients (17%). All of them were heterogeneous hematomas in CT scans. Except for 4 patients, all EDHs were associated with skull fracture(s) (87%). There was no case of patient with major organ injury. CT or MRI revealed brain contusion in 5 patients, and diffuse axonal injury in one patient The mortality was zero, and the outcomes were excellent in 26 and good in 2 patients. None of the tested variables were found to have a prognostic relevance. Conclusion: Regardless of the EDH size, the clinical status of the patients, the abnormal pupillary findings, or the cause of injury, the outcome and prognosis of the patients with EDH were excellent.

• Journal of Korean Neurosurgical Society
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• v.46 no.2
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• pp.87-92
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• 2009

Objective: Chronic subdural hematoma (CSDH) is one of the most common types of traumatic intracranial hemorrhage, usually occurring in the older patients, with a good surgical prognosis. Burr hole craniostomy is the most frequently used neurosurgical treatment of CSDH. However, there have been only few studies to assess the role of the number of burr holes in respect to recurrence rates. The aim of this study is to compare the postoperative recurrence rates between one and two burr craniostomy with closed-system drainage for CSDH. Methods: From January 2002 to December 2006, 180 consecutive patients who were treated with burr hole craniostomy with closed-system drainage for the symptomatic CSDH were enrolled. Pre- and post-operative computed tomography (CT) scans and/or magnetic resonance imaging (MRI) were used for radiological evaluation. The number of burr hole was decided by neurosurgeon's preference and was usually made on the maximum width of hematoma. The patients were followed with clinical symptoms or signs and CT scans. All the drainage catheters were maintained below the head level and removed after CT scans showing satisfactory evacuation. All patients were followed-up for at least 1 month after discharge. Results: Out of 180 patients, 51 patients were treated with one burr hole, whereas 129 were treated with two burr holes. The overall postoperative recurrence rate was 5.6% (n = 10/180) in our study. One of 51 patients (2.0%) operated on with one burr hole recurred, whereas 9 of 129 patients (7.0%) evacuated by two burr holes recurred. Although the number of burr hole in this study is not statistically associated with postoperative recurrence rate (p> 0.05), CSDH treated with two burr holes showed somewhat higher recurrence rates. Conclusion: In agreement with previous studies, burr hole craniostomy with closed drainage achieved a good surgical prognosis as a treatment of CSDH in this study. Results of our study indicate that burr hole craniostomy with one burr hole would be sufficient to evacuate CSDH with lower recurrence rate.

• Journal of radiological science and technology
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• v.26 no.3
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• pp.33-39
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• 2003

Purpose : Be aware of clinical possibilities on image quality by comparison of contrast-enhanced dynamic CT and MR imaging applied of MIP technique after the experimentally induced clonorchasis infection in dogs. Materials and Method : Twenty mongrel dogs prepared in zoo-laboratory were followed up with serial CT scans and MR imaging for 13 weeks after the experimental infection in liver. Two-phase helical CT was acquired in the supine position with the following scanning parameters. After the injection of contrast material, the arterial phase was initiated using a bolus-racking method. The portal phase scan was started 15 seconds after the arterial phase scan. CT protocol was determined after single level dynamic scans. MR imaging used the CP body coil and images get a 2D image using HASTE, FLASH, TSE pulse sequence. Bile duct MR imaging were obtained in three plans. Then each image was post processed by using target MIP algorithm. Two experimentation above, as a method of evaluation, one pathologist, three radiologist and five radiological technologist were analyzed visually for evaluation of following findings, enhancement of the bile duct wall, dilatation of bile duct tip, liver parenchyma, background suppression. Results : Five dogs was died of a disease after the infection, the rest one else shows the chronic dilatation of the intrahepatic bile duct with CT and MR imaging. Contrast administration of CT shows the contrast-enhanced of the bile duct walls with live parenchyma. MR imaging calculated of CNR and CR from pulse sequence for comparative evaluation and shows the pattern of the intrahepatic bile duct, dilatation of bile duct tip using MIP technique. CNR of the clonorchiasis, HASTE was $16{\pm}0.83$, TSE $7.06{\pm}3.0$, FLASH $1.19{\pm}0.2$ and CR, HASTE was 73.3%, TSE 62.3%, FLASH 6.4%. Conclusion : CT and MR imaging is very usefulness in diagnosis of dog clonorchiasis.

• Journal of the Korean Society of Radiology
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• v.17 no.7
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• pp.1033-1039
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• 2023

Low-dose chest CT, which is used as a lung screening test, also includes information on coronary artery calcification within the scan range. The purpose of this study was to investigate the usefulness of determining coronary artery calcification using Low-dose chest CT. Those who underwent low-dose chest CT and coronary artery calcification score CT on the same day were eligible. Coronary artery calcium score CT results were divided into 4 groups (Low: 1〈CACS〈10, Mild: 10〈CACS〈100, Moderate: 100〈CACS〈400, High: 400〈CACS) by referring to the Coronary artery calcium score categories and risks. After selecting 30 people each group, five radiotechnologists with more than 15 years of experience in coronary artery calcium measurement retrospectively analyzed the presence or absence of coronary artery calcification in low-dose chest CT images. The results of the five observers' uniform interpretation of the low-dose chest CT image were consistent with the coronary artery calcium score CT results in Low group: 56%, Mild group: 96.6%, Moderate group: 100%, and High group: 100%. appeared. In the Low group, all 5 observers observed calcification in 17 out of 30 cases, and in 7 cases all 5 observers decided that calcification could not be identified. Coronary artery calcification could be observed in 100% of asymptomatic adults with a calcium score of 15 or higher in low-dose chest CT scans. The minimum calcium score that can be identified is 1, and it was found that even very small calcifications can be identified when the subject's body size is small or the scan is performed at a time when heart movement is minimal.

• Journal of Chest Surgery
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• v.39 no.8 s.265
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• pp.573-578
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• 2006

Background: Generally hernia is diagnosed with simple chest or gastrointestinal x-ray. Sometimes CT or MRI can give lots of information for the diagnosis. However, there was no study for the differentiation with using CT findings between Morgagni hernia and pleuropericardial fat. The aim of this study was to evaluate the useful CT findings for differentiating Morgagni hernia from pleuropericardial fat. Material and Method: We retrospectively analyzed CT scans of eight patients with Morgagni hernia and 20 patients with abundant pleuropericardial fat without peridiaphragmatic lesions. All CT scans were performed with coverage of the whole diaphragm in the inspiration state. We evaluated 1) the presence of the defect of the anterior diaphragm, 2) the interface between the lung and fat, 3) the angle between the chest wall and fat, 4) the continuity between the extrapleural fat and fat, 5) the presence of the vessels within fat, and 6) the presence of a thin line surrounding fat. Result: In all cases with Morgagni hernia, the defect of the anterior diaphragm was seen. The interface was well-defined, smooth, and convex to the lung. The angle with the chest wall was acute. The continuity with the extrapleural fat was not seen. In the cases with abundant pleuropericardial fat, the defect of the anterior diaphragm was seen in three (15%). The interface was usually irregular (n=10) and flat (n=17). The angle with the chest wall was variable. The continuity with the extrapleural fat, that was markedly increased in amount, was usually seen (n=16). The thin line surrounding fat was seen in four cases with Morgagni hernia, however, not seen in all cases with pleuropericardial fat. All of the above findings were statistically significant, however, vessels within fat was not significant to differentiate Morgagni hernia (n=8/8) from pleuropericardial fat (n=14/20). Conclusion: The useful CT findings of Morgagni hernia were fatty mass with sharp margin, convexity toward lung, acute angle with chest wall, and thin line surrounding hernia. Branching structure within fatty mass representing omental vessels that has been known as a characteristic finding of Morgagni hernia was not useful for differentiating Morgagni hernia from pleuropericardial fat.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.3
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• pp.247-251
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• 2007

A 38-year-old man who was diagnosed with malignant paraganglioma underwent computed tomography (CT) and I-131 metaiodobenzylguanidine (MIBG) san. CT showed extensive lymph node enlargement in right iliac area and retroperitoneum with severe hydronephrosis and mass on posterior bladder wall. However, I-131 MIBG scan didn't showed abnormal uptake. He also underwent F-18 fluorodeoxyglucose (FDG) positron emisson tomography/CT for localizing accurate tumor site. F-18 FDG PET/CT showed multiple metastases of left supraclavicular, hilar, mediastinal para-aortic, inguinal, right iliac lymph nodes, lung, vertebrae, and pelvis. There are a few reports showing that the F-18 FDG PET/CT is helpful for staging and localizing tumor site of patients who are diagnosed with negative on the MIBG scans. Thus, we report a case with paraganglioma which showed negative I-131 MIBG scan, but revealed multiple intense hypermetabolic foci in F-18 FDG PET/CT.

• Journal of Biomedical Engineering Research
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• v.28 no.1
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• pp.95-101
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• 2007

Recently, small-animal imaging technology has been rapidly developed for longitudinal screening of laboratory animals such as mice and rats. One of newly developed imaging modalities for small animals is an x-ray micro-CT (computed tomography). We have developed two types of x-ray micro-CT systems for small animal imaging. Both systems use flat-panel x-ray detectors and micro-focus x-ray sources to obtain high spatial resolution of $10{\mu}m$. In spite of the relatively large field-of-view (FOV) of flat-panel detectors, the spatial resolution in the whole-body imaging of rats should be sacrificed down to the order of $100{\mu}m$ due to the limited number of x-ray detector pixels. Though the spatial resolution of cone-beam CTs can be improved by moving an object toward an x-ray source, the FOV should be reduced and the object size is also limited. To overcome the limitation of the object size and resolution, we introduce zoom-in micro-tomography for high-resolution imaging of a local region-of-interest (ROI) inside a large object. For zoom-in imaging, we use two kinds of projection data in combination, one from a full FOV scan of the whole object and the other from a limited FOV scan of the ROI. Both of our micro-CT systems have zoom-in micro-tomography capability. One of both is a micro-CT system with a fixed gantry mounted with an x-ray source and a detector. An imaged object is laid on a rotating table between a source and a detector. The other micro-CT system has a rotating gantry with a fixed object table, which makes whole scans without rotating an object. In this paper, we report the results of in vivo small animal study using the developed micro-CTs.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.14 no.6
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• pp.2480-2496
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• 2020

Considering that high-dose X-ray radiation during CT scans may bring potential risks to patients, in the medical imaging industry there has been increasing emphasis on low-dose CT. Due to complex statistical characteristics of noise found in low-dose CT images, many traditional methods are difficult to preserve structural details effectively while suppressing noise and artifacts. Inspired by the deep learning techniques, we propose a densely connected residual network (DCRN) for low-dose CT image noise cancelation, which combines the ideas of dense connection with residual learning. On one hand, dense connection maximizes information flow between layers in the network, which is beneficial to maintain structural details when denoising images. On the other hand, residual learning paired with batch normalization would allow for decreased training speed and better noise reduction performance in images. The experiments are performed on the 100 CT images selected from a public medical dataset-TCIA(The Cancer Imaging Archive). Compared with the other three competitive denoising algorithms, both subjective visual effect and objective evaluation indexes which include PSNR, RMSE, MAE and SSIM show that the proposed network can improve LDCT images quality more effectively while maintaining a low computational cost. In the objective evaluation indexes, the highest PSNR 33.67, RMSE 5.659, MAE 1.965 and SSIM 0.9434 are achieved by the proposed method. Especially for RMSE, compare with the best performing algorithm in the comparison algorithms, the proposed network increases it by 7 percentage points.