• Journal of the Korea Computer Graphics Society
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• v.23 no.5
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• pp.19-27
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• 2017

In this paper, we propose an automatic segmentation method of the mandible using shape-constrained information in cranio-maxillo-facial CBCT images. The proposed method consists of the following two steps. First, the mandible segmentation based on the global shape information is performed through the statistical shape model generated using the MDCT images. Second, improvement of mandible segmentation is performed considering the local shape information and intensity characteristics of the mandible. To evaluate the performance of the proposed method, the proposed method was evaluated qualitatively and quantitatively based on the results of manual segmentation by expert. Experimental results show that the Dice Similarity Coefficient of the proposed method was 95.64% and 90.97%, respectively, in the mandible body region including the narrow region of large curvature and the condyle region with large positional variance.

• Journal of Korea Multimedia Society
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• v.14 no.11
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• pp.1383-1391
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• 2011

Following the appearance of the latest medical equipment with improved function, the importance of image analysis which enables effective image processing and analysis consistent with the hardware performance is on the rise. As well as, ongoing study is being done on the 2D medical image processing and 3D reconstruction. This paper segments chest CT images into each stage and finally shows 3D reconstruction of each segmented result. Among various image segmentation methods, Region Growing and apply sharpening and Gamma Controller as for image improvement for effective segmentation, image segmentation in order of bronchus and lung, bronchus, lung. Human organs image of segmented is use VTK(Visualization Toolkit) to make 3D reconstruction, two and three-dimensional medical image processing and analysis for lesions diagnosis are able to utilized.

• Imaging Science in Dentistry
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• v.51 no.1
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• pp.41-47
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• 2021

Purpose: This study aimed to compare the accuracy of 3-dimensional(3D) printed models derived from multidetector computed tomography (MDCT) and cone-beam computed tomography (CBCT) systems with different fields of view (FOVs). Materials and Methods: Five human dry mandibles were used to assess the accuracy of reconstructions of anatomical landmarks, bone defects, and intra-socket dimensions by 3D printers. The measurements were made on dry mandibles using a digital caliper (gold standard). The mandibles then underwent MDCT imaging. In addition, CBCT images were obtained using Cranex 3D and NewTom 3G scanners with 2 different FOVs. The images were transferred to two 3D printers, and the digital light processing (DLP) and fused deposition modeling (FDM) techniques were used to fabricate the 3D models, respectively. The same measurements were also made on the fabricated prototypes. The values measured on the 3D models were compared with the actual values, and the differences were analyzed using the paired t-test. Results: The landmarks measured on prototypes fabricated using the FDM and DLP techniques based on all 4 imaging systems showed differences from the gold standard. No significant differences were noted between the FDM and DLP techniques. Conclusion: The 3D printers were reliable systems for maxillofacial reconstruction. In this study, scanners with smaller voxels had the highest precision, and the DLP printer showed higher accuracy in reconstructing the maxillofacial landmarks. It seemed that 3D reconstructions of the anterior region were overestimated, while the reconstructions of intra-socket dimensions and implant holes were slightly underestimated.

• Journal of International Society for Simulation Surgery
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• v.1 no.1
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• pp.41-44
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• 2014

The aim of this report is showing the case that we could give exact navigation of perigastric vessels for gastrectomy with 3D CTA. A 74-year-old male patient visited hospital with gastric cancer. Early gastric cancer, type IIb was found at stomach antrum great curvature side. Before surgery, he underwent 3D CT angiography. 3D volume rendering images and MIP images were made by post processing. He had replaced Lt. hepatic artery arising from Lt. gastric artery. Surgeon could get patient's specific vascular anatomy before surgery including surgically relevant anatomical distance and direction and could finish gastrectomy within 4 hours and just 53ml blood loss.

• Journal of the Korean Society of Radiology
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• v.16 no.1
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• pp.67-75
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• 2022

The aim of this study is to establish a new QC method that can simultaneously evaluate the resolution of the x/y plane and the z-axis by producing a phantom that can reflect exposure and reconstruction parameter of MDCT system. It was used with Aquilion ONE(Cannon Medical System, Otawara, Japan), and the examination was scanned using of 120 kV, 260 mA, and the D-FOV of 300 mm². It produced new SSP phantom modules in which two aluminum plates inclined at 45° to a vertical axis and a transverse axis to evaluate high contrast resolution of x/y plane and z axis. And it changed factors such as the algorithm, distance from gantry iso-center. All images were reconstructed in five steps from 0.6 mm to 10.0 mm slice thickness to measure resolution of x/y plane and z-axis. The image data measured FWHM and FWTM using Profile tool of Aquarius iNtusion Edition ver. 4.4.13 P6 software(Terarecon, California, USA), and analysed SPQI and signal intensity by ImageJ program(v1.53n, National Institutes of Health, USA). It decreased by 4.09~11.99%, 4.12~35.52%, and 4.70~37.64% in slice thickness of 2.5 mm, 5.0 mm, and 10.0 mm for evaluating the high contrast resolution of x/y plane according to distance from gantry iso-center. Therefore, the high contrast resolution of the x/y plane decreased when the distance from the iso-center increased or the slice thickness increased. Additionally, the slice thicknesses of 2.5 mm, 5.0 mm, and 10.0 mm with a high algorithm increased 74.83, 15.18 and 81.25%. The FWHM was almost constant on the measured SSP graph for evaluating the accuracy of slice thickness which represents the resolution of x/y plane and z-axis, but it was measured to be higher than the nominal slice thickness set by user. The FWHM and FWTM of z-axis with axial scan mode tended to increase significantly as the distance increased from gantry iso-center than the helical mode. Particularly, the thinner slice thickness that increased error range compare with the nominal slice thickness. The SPQI increased with thick slice thickness, and that was closer to 90% in the helical scan than the axial scan. In conclusion, by producing a phantom suitable for MDCT detectors and capable of quantitative resolution evaluation, it can be used as a specific method in the management of research quality and management of outdated equipment. Thus, it is expected to contribute greatly to the discrimination of lesions in the field of CT imaging.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.84-91
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• 2017

This study was performed using Somatom Definition Flash (Siemens, Enlarge, Germany) and GE 64-MDCT (Discovery 750 HD, GE HEALTHCARE, Milwaukee, USA.) using high-density medical materials that (are indispensable to?) computed tomography. We analyzed quantitatively the rate of change of the CT number of the CT reconstruction images by means of the IMAR and MAR algorithms using the phantom images acquired after scanning and previously captured raw data images. As a result, it was shown that the IMAR and MAR algorithms provided if ferent phantom images in the case of all medical high-density materials (p <0.05). The black streak artifacts were analyzed using the MAR and IMAR algorithms to determine if they corresponded to stainless steel materials (p>0.05). Also, it was found that the application of the IMAR algorithm affects the attenuation deviation, because there is a change in the image CT number compared to that before. The results suggest that, in the future, after the implant procedure, it would be useful to observe the surgical site and surrounding tissues during follow-up CT scans.

• The Journal of the Korea Contents Association
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• v.11 no.10
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• pp.333-341
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• 2011

To compare between calcium scoring CT (CSCT) and Low-dose CT (LDCT) image finding for coronary artery calcification (CAC) in screening of lung disease by MDCT. A total of 61 subjects who retired-workers exposed to inorganic dust were performed LDCT and CSCT by using a MDCT scanner on the same day, after be approved by the institutional review board, and obtaining the written informed consent from all subjects. LDCT images were read for detecting lung diseases as well as CAC by a experienced chest radiologist, then the subjects were divided either the positive group with CAC or the negative group without it. The CSCT was used to quantify and detect the presence of calcification in the coronary artery, and score of CAC calculated by using a Rapidia software (ver 2.8). In all coronary arteries, calcium score of positive group was higher better than that in negative group, especially in the total calcium (13.7 vs. 582.9, p=0.008) and the left anterior descending artery (3.2 vs. 249.0, p=0.006). CAC findings between CSCT and LDCT image were showed excellent agreement in cut-off point 100(K-value=0.80, 95% CI=0.69-0.91) from total calcium score. CAC findings on LDCT images showed the higher relation with CSCT. Therefore, the obstructive coronary artery disease could be predicted by CAC on LDCT images for screening of lung diseases.

• Journal of Yeungnam Medical Science
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• v.26 no.1
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• pp.15-23
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• 2009

Constant technological developments in coronary artery disease have contributed to the assessment of both the presence of coronary stenosis and its hemodynamic consequences. Hence, noninvasive imaging helps guide therapeutic decisions by providing complementary information on coronary morphology and on myocardial perfusion and metabolism. This can he done using single photon emission computed tomography (SPECT) or positron emission tomography (PET) and multidetector CT (MDCT). Advances in image-processing software and the advent of SPECT/CT and PET/CT have paved the way for the combination of image datasets from different modalities, giving rise to hybrid imaging. Three dimensional cardiac hybrid imaging helped to confirm hemodynamic significance in many lesions, add new lesions such as left main coronay artery disease, exclude equivocal defects, correct the corresponding arteries to their allocated defects and identify culprit segment. Cardiac hybrid imaging avoids the mental integration of functional and morphologic images and facilitates a comprehensive interpretation of coronaty lesions and their pathophysiologic adequacy by three dimensional display of fused images, and allows the best evaluation of myocardial territories and the coronary-artery branches that serve each territory. This integration of functional and morphological information were feasible to intuitively convincing and might facilitate development of a comprehensive non-invasive assessment of coronary artery disease.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.37-46
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• 2023

This study aims to evaluate the usefulness of Deep Learning Image Reconstruction (TrueFidelity, TF), the image quality of existing Filtered Back Projection (FBP) and Adaptive Statistical Iterative Reconstruction-Veo (ASIR-V) were compared. Noise, CNR, and SSIM were measured by obtaining images with doses fixed at 17.29 mGy and altered to 10.37 mGy, 12.10 mGy, 13.83 mGy, and 15.56 mGy in reconstruction techniques of FBP, ASIR-V 50%, and TF-H. TF-H has superior image quality compared to FBP and ASIR-V when the reconstruction technique change is given at 17.29 mGy. When dose changes were made, Noise, CNR, and SSIM were significantly different when comparing 10.37 mGy TF-H and FBP (p<0.05), and no significant difference when comparing 10.37 mGy TF-H and ASIR-V 50% (p>0.05). TF-H has a dose-reduction effect of 30%, as the highest dose of 15.56 mGy ASIR-V has the same image quality as the lowest dose of 10.37 mGy TF-H. Thus, Deep Learning Reconstruction techniques (TF) were able to reduce dose compared to Iterative Reconstruction techniques (ASIR-V) and Filtered Back Projection (FBP). Therefore, it is considered to reduce the exposure dose of patients.

• The Korean Journal of Pain
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• v.26 no.2
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• pp.130-134
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• 2013

Background: The aims of this study were to analyze the anatomic variations of supraorbital foramina/notches in Koreans and to compare the results with those of previous studies examining other races. We evaluated the three-dimensional computed tomography (3D-CT) images of human faces using multidetector computed tomography (MDCT). Methods: A total of 395 adults (232 men and 163 women) were enrolled and the 3D-CT images of their faces were reviewed in this study. In this study, the data from the images included the presence, shape, width and distance from the nasion to the supraorbital foramina/notches. ANOVA was used to assess the main effects of gender and side (right or left foramen/notch), and comparisons of the means were done by paired t-test. Results: The most common shapes in Koreans were a single notch (39.5%) on the right hand side and a single foramen (42.3%) on the left hand side. The incidence of a single foramen in Koreans was high compared to other races. The mean foramen diameter was $2.34{\pm}0.78$ mm, and the mean distance from the nasion was $27.19{\pm}4.03$ mm. The mean notch diameter was $3.37{\pm}1.71$ mm, and the mean distance from the nasion was $23.42{\pm}2.45$ mm. Conclusions: This is the first study on the variations of supraorbital foramina/notches in Koreans using 3D-CT images of faces. The anatomic characteristics of the supraorbital foramina/notch will help in performing nerve blocks and maxillofacial surgery.