• Progress in Medical Physics
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• v.9 no.1
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• pp.47-53
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• 1998

Nuclear Medicine Images have comparatively poor spatial resolution, making it difficult to relate the functional information which they contain to precise anatomical structures. Anatomical structures useful in the interpretation of SPECT /PET Images were radiolabelled. PET/SPECT Images Provide functional information, whereas MRI mainly demonstrate morphology and anatomical. Fusion or Image Registration improves the information obtained by correlating images from various modalities. Brain Scan were studied on one or more occations using MRI and SPECT. The data were aligned using a point pair methods and surface matching. SPECT and MR Images was tested using a three dimensional water fillable Hoffman Brain Phantom with small marker and PET and MR Image was tested using a patient data. Registration of SPECT and MR Images is feasible and allows more accurate anatomic assessment of sites of abnormal uptake in radiolabeled studies. Point based registration was accurate and easily implemented three dimensional registration of multimodality data set for fusion of clinical anatomic and functional imaging modalities. Accuracy of a surface matching algorithm and homologous feature pair matching for three dimensional image registration of Single Photon Emission Computed Tomography Emission Computed Tomography (SPECT), Positron Emission Tomography (PET) and Magnetic Resonance Images(MRD was tested using a three dimensional water fill able brain phantom and Patients data. Transformation parameter for translation and scaling were determined by homologous feature point pair to match each SPECT and PET scan with MR images.

• Journal of radiological science and technology
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• v.33 no.4
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• pp.355-362
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• 2010

This study determines a range of CT parameter values in Brain CT which are minimizing patient absorption dose without compromising the image quality and optimal exposure condition. We measured dose and image noise using conventional CT parameters in Brain CT. In additon, we evaluated dose, SNR and PSNR of head phantom images while changing kVp and rotation time. In this study, effectiveness of dose that was achieved from dose reproducible experiments in conventional head CT condition is determined by changing kVp and rotation time. Dose and PSNR is related to low dose-high resolution condition. In conclusion, we suggest that using proposed conditions is effective for imaging to compare with conditions proposed by the manufacturer.

• The Journal of the Korea Contents Association
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• v.7 no.4
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• pp.184-191
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• 2007

Our objective was to develop and evaluate a non-invasive device for rigid immobilization and surface disease non-contact of the table in the lower extremity during CT angiography. The immobilization device consists of two components. The patient's lower limb device stabilizing elements made of polyethylene resin soft materials, and pelvis parts foam pad is used for non-contact surface. In a Prospective study the lower extremity device was used in patients who underwent a CT angiography of the lower limb. Immobilization with our device was well tolerated by all patients. The quality of the resulting images in the popliteal and infrapopliteal region was rated by five-point scale. The rigid immobilization resulted in a complete absence of motion artifacts. The new device is an effective, well tolerated and easily used immobilization that is suitable of use in 3D lower extremity CT angiography.

• Korean Journal of Biological Psychiatry
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• v.2 no.2
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• pp.169-176
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• 1995

두부 외상은 많은 발생율과 사망율을 차지하고 있으며, 건강한 생활을 위해 큰 관심을 갖게 되었다. 신경방사선영상은 외상성 뇌손상 환자들의 진단과 치료에 필수적인 방법이다. 뇌손상의 기본 기전, 병리, 그리고 영상 소견을 이해 하는 것은 매우 중요하다. 1970년대에 Glasgow coma scale의 형상과 전산화단층촬영(CT)의 발달은 임상의사들이 두부외상에 대한 평가와 환자들의 경과를 예상하는데 극적인 변화를 주었다. 최근 자기공명영상(MRI)의 발달로 외상성 뇌손상의 형태를 더욱 이해 하게 되었고, 두부 외상의 발견율이 높아지게 되었다.

• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1441-1476
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• 2021

The tracheobronchial tree is a system of airways that allows the passage of air to aerate the lungs and entire body. Several pathological conditions can affect this anatomical region. Multidetector CT (MDCT) helps identify and characterize various large airway diseases. Post-processing tools, such as virtual bronchoscopy and automatic lung analysis, can help enhance the performance of imaging studies. In this pictorial essay review, we provide imaging findings of various bronchial lesions manifested as wall thickening and endoluminal nodules on conventional MDCT and advanced image visualization and analysis.

• Journal of the Korean Society of Radiology
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• v.14 no.3
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• pp.211-220
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• 2020

High-quality computed tomography (CT) images enable precise lesion detection and accurate diagnosis. A lot of studies have been performed to improve CT image quality while reducing radiation dose. Recently, deep learning-based techniques for improving CT image quality have been developed and show superior performance compared to conventional techniques. In this study, a super-resolution convolutional neural network (SRCNN) model was used to improve the spatial resolution of CT images, and image quality according to the hyperparameters, which determine the performance of the SRCNN model, was evaluated in order to verify the effect of hyperparameters on the SRCNN model. Profile, structural similarity (SSIM), peak signal-to-noise ratio (PSNR), and full-width at half-maximum (FWHM) were measured to evaluate the performance of the SRCNN model. The results showed that the performance of the SRCNN model was improved with an increase of the numbers of epochs and training sets, and the learning rate needed to be optimized for obtaining acceptable image quality. Therefore, the SRCNN model with optimal hyperparameters is able to improve CT image quality.

• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.217-221
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• 2024

Retroperitoneal ectopic pregnancy is a rare form of ectopic pregnancy. Owing to its rarity and nonspecific symptoms, diagnosing retroperitoneal ectopic pregnancy at the initial presentation poses a significant challenge. Typically, the diagnosis relies on non-radiation imaging modalities, such as ultrasonography and MRI, whereas CT is infrequently used. Herein, we report a rare case of a retroperitoneal ectopic pregnancy, which was diagnosed using CT.

• Journal of the Korean Society of Radiology
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• v.81 no.2
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• pp.250-271
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• 2020

Assessment of myocardial ischemia in patients with stable angina is important in deciding whether to treat coronary artery disease and in predicting clinical outcome. The fractional flow reserve is a standard reference for the diagnosis of myocardial ischemia, but this procedure has limitations because of its invasiveness. Coronary computed tomography angiography (CCTA) is now an established tool in the anatomic diagnosis of coronary artery disease; however, there are limits to the diagnosis of hemodynamically important stenosis that causes myocardial ischemia. In order to address this problem, studies using quantification of coronary atherosclerotic plaques, myocardial perfusion, and noninvasive calculation of fractional flow reserve based on CCTA have been actively conducted and recognized for their diagnostic value. In this review, several imaging techniques of CCTA used to assess myocardial ischemia are described.

• Journal of radiological science and technology
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• v.34 no.3
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• pp.215-219
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• 2011

Monte Carlo simulation was performed to investigate optimal system of proton computed tomography and to avoid the errors by using data from X ray computed tomography in proton therapy. The informations from two DSSDs to measure position and LYSO scintillation detector to measure the residual energy of proton particle in GEANT4 were used for reconstruction computed tomography.

• Journal of the Korean Society of Radiology
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• v.81 no.3
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• pp.644-653
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• 2020

Purpose We aimed to analyze postoperative multidetector CT (MDCT) of acquired spondylolysis and spondylolisthesis after posterior lumbar laminectomy. Materials and Methods We enrolled 74 patients, from 2003 to 2017, who underwent posterior lumbar laminectomy with both pre and postoperative MDCT. The patients were categorized into the following two groups: group 1 without fusion and group 2 with fusion. We analyzed laminectomy width, level and location of spondylolysis or spondylolisthesis, facet changes, and fatty infiltration of paraspinal muscles on postoperative MDCT. Results Incidence of spondylolysis or spondylolisthesis was 4 of 20 patients in group 1 and 2 of 54 patients in group 2. The laminectomy width (%) was defined as the percentage of the width of laminectomy to total lamina length. Mean laminectomy width (%) in patients with spondylolysis or spondylolisthesis was 54.0 in group 1 and 53.2 in group 2, in contrast to that in patients without spondylolysis or spondylolisthesis, which was 35.0 in group 1. The spondylolysis was observed at the level of the laminectomy and below pars interarticularis in group 1 and below the fusion mass at isthmic region in group 2. Conclusion MDCT facilitates the diagnosis of postsurgical acquired spondylolysis and spondylolisthesis and demonstrates typical location of spondylolysis. Greater laminectomy width has been associated with occurrence of acquired spondylolysis and spondylolisthesis.