• Imaging Science in Dentistry
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• v.34 no.3
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• pp.151-157
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• 2004

Purpose : To evaluate the quantitative accuracy of three-dimensional (3D) images by means of comparing distance measurements on the 3D images with direct measurements of dry human skull according to slice thickness and scanning modes. Materials and Mathods : An observer directly measured the distance of 21 line items between 12 orthodontic landmarks on the skull surface using a digital vernier caliper and each was repeated five times. The dry human skull was scanned with a Helical CT with various slice thickness (3, 5, 7 mm) and acquisition modes (Conventional and Helical). The same observer measured corresponding distance of the same items on reconstructed 3D images with the internal program of V-works 4.0/sup TM/(Cybermed Inc., Seoul, Korea). The quantitative accuracy of distance measurements were statistically evaluated with Wilcoxons' two-sample test. Results: 11 line items in Conventional 3 mm, 8 in Helical 3mm, 11 in Conventional 5mm, 10 in Helical 5mm, 5 in Conventional 7mm and 9 in Helical 7mm showed no statistically significant difference. Average difference between direct measurements and measurements on 3D CT images was within 2mm in 19 line items of Conventional 3mm, 20 of Helical 3mm, 15 of Conventional 5mm, 18 of Helical 5mm, II of Conventional 7mm and 16 of Helical 7mm. Conclusion: Considering image quality and patient's exposure time, scanning protocol of Helical 5mm is recommended for 3D image analysis of the skull in CT.

• Journal of Microbiology and Biotechnology
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• v.18 no.8
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• pp.1453-1458
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• 2008

For quantitative PCR assay of Salmonella enterica serovar Typhimurium in food samples, a real-time PCR method was developed, based on DNA genome equivalent. Specific primers and probe designed based on the STM4497 gene of S. Typhimurium LT2 showed the specificity to S. Typhimurium. Threshold cycle (Ct) values of real-time PCR were obtained from a quantitative standard curve with genomic DNA of Salmonella Typhimurium. In addition, the recovery of S. Typhimurium inoculated artificially to chicken samples with $4.5{\times}10^5$ to 4.5 CFU/ml was evaluated by using real-time PCR and plate-count methods. Result showed that the number of cells calculated from the real-time PCR method had good correlation with that of the plate-count method. This real-time PCR method could be applicable to the detection and quantification of S. Typhimurium in food samples.

• Imaging Science in Dentistry
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• v.52 no.3
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• pp.245-258
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• 2022

Purpose: This study compared the root canal anatomy between cone-beam computed tomography (CBCT) and micro-computed tomography (micro-CT) images before and after biomechanical preparation and root canal filling. Materials and Methods: Isthmus-containing mesial roots of mandibular molars(n=14) were scanned by micro-CT and 3 CBCT devices: 3D Accuitomo 170 (ACC), NewTom 5G (N5G) and NewTom VGi evo (NEVO). Two calibrated observers evaluated the images for 2-dimensional quantitative parameters, the presence of debris or root perforation, and filling quality in the root canal and isthmus. The kappa coefficient, analysis of variance, and the Tukey test were used for statistical analyses(α=5%). Results: Substantial intra-observer agreement (κ=0.63) was found between micro-CT and ACC, N5G, and NEVO. Debris detection was difficult using ACC (42.9%), N5G (40.0%), and NEVO (40%), with no agreement between micro-CT and ACC, N5G, and NEVO (0.05<κ<0.12). After biomechanical preparation, 2.4%-4.8% of CBCT images showed root perforation that was absent on micro-CT. The 2D parameters showed satisfactory reproducibility between micro-CT and ACC, N5G, and NEVO (intraclass correlation coefficient: 0.60-0.73). Partially filled isthmuses were observed in 2.9% of the ACC images, 8.8% of the N5G and NEVO images, and 26.5% of the micro-CT images, with no agreement between micro-CT and ACC, and poor agreement between micro-CT and N5G and NEVO. Excellent agreement was found for area, perimeter, and the major and minor diameters, while the roundness measures were satisfactory. Conclusion: CBCT images aided in isthmus detection and classification, but did not allow their classification after biomechanical preparation and root canal filling.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.8
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• pp.126-131
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• 2009

Acetabular dysplasia is a condition defined by inadequate development of an individual's acetabulum. Individual diversity of the symptoms in this disease needs safe and accurate preoperative planning. Technologies that utilize multidimensional image information are thus important. The assessment method by Janzen et al. was suggested a coefficient method in evaluation of acetabular dysplasia. In this study, we applied it, using a three-dimensional computed tomography (3D CT) on the koreans. 19 cases of the normal hips and 4 cases of the acetabular dysplasia were investigated to evaluate the proved method; 3D CT was used to define the geometric center of the femoral head and to measure center edge angles at $10^{\circ}$ rotational increments around the acetabular rim. Mean and standard deviation in CEAs (Center Edge Angle) of normal 19 hips at $10^{\circ}$ rotational increments from anterior to posterior rim were determined, and termed as a 'normal curve'. Then this normal values were compared with the CEA data measured from 4 cases of acetabular dysplasia patiens. Quantative comparison of the CEA values between the normal cases and dysplasia cases was successfully demonstrated, and thus, we claim that this simple CT method of assessing acetabular dysplasia can be well applicable to diagnosis, quantification and surgical planning for adult acetabular dysplasia patients.

• International Journal of Oral Biology
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• v.38 no.3
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• pp.87-92
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• 2013

Periodontal inflammation increases the risk of tooth loss, particularly in cases where there is an associated loss of alveolar bone and periodontal ligament (PDL). Histological and morphometric evaluation of periodontal inflammation is difficult. Especially, the lengths of the periodontal ligament and interdental alveolar bone space have not been quantified. A quantitative imaging procedure applicable to an animal model would be an important clinical study. The purpose of this study was to quantify the loss of alveolar bone and periodontal ligament by evaluation with micro-computed tomography (micro-CT). Another purpose was to investigate differences in infections with systemic E. coli LPS and TNF-${\alpha}$ on E. coli lipopolysaccharide (LPS) in loss of alveolar bone and periodontal ligament model on mice. This study showed that linear measurements of alveolar bone loss were represented with an increasing trend of the periodontal ligament length and interdental alveolar process space. The effects of systemic E. coli LPS and TNF-${\alpha}$ on an E. coli LPS-induced periodontitis mice model were investigated in this research. Loss of periodontal ligament and alveolar bone were evaluated by micro-computed tomography (micro-CT) and calculated by the two- and three dimensional microstructure morphometric parameters. Also, there was a significantly increasing trend of the interdental alveolar process space in E. coli LPS and TNF-${\alpha}$ on E. coli LPS compared to PBS. And E. coli LPS and TNF-${\alpha}$ on E. coli LPS had a slightly increasing trend of the periodontal ligament length. The increasing trend of TNF-${\alpha}$ on the LPS-induced mice model in this experiment supports the previous studies on the contribution of periodontal diseases in the pathogenesis of systemic diseases. Also, our findings offer a unique model for the study of the role of LPS-induced TNF-${\alpha}$ in systemic and chronic local inflammatory processes and inflammatory diseases. In this study, we performed rapidly quantification of the periodontal inflammatory processes and periodontal bone loss using micro-computed tomography (micro-CT) in mice.

• Investigative Magnetic Resonance Imaging
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• v.20 no.4
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• pp.241-249
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• 2016

Purpose: To evaluate the added value of diffusion weighted imaging (DWI) to computed tomography (CT) for detecting pancreatic abnormality in patients with clinically suspected acute pancreatitis (AP). Materials and Methods: 203 patients who underwent abdomen CT and subsequent DWI to do a workup for epigastric pain were analyzed. Two blinded radiologists independently performed an interval reading based on CT image sets first, then based on combined CT and DWI image sets. The diagnostic criterion on DWI was the increased signal intensity in the pancreas to that of the spleen. For quantitative analysis, the third radiologist measured ADC value of the pancreas in each patient. Results: For AP (n = 43), the sensitivity for detecting pancreatic abnormality increased, from 42% to 70% for reader 1 (P < 0.05) and from 44% to 72% for reader 2 (P < 0.05). For borderline pancreatitis (n = 42), the sensitivity also increased, from 10% to 26% for reader 1 (P < 0.05) and from 7% to 29% for reader 2 (P < 0.05). The mean ADC values (unit, ${\times}10^{-3}mm^2/s$) were significantly different among the three groups (for AP, $1.09{\pm}0.16$; for borderline pancreatitis, $1.28{\pm}0.2$; for control, $1.46{\pm}0.15$, P < 0.05). Conclusion: Sensitivity for detecting pancreatic abnormality increased significantly after adding DWI to CT in patients with clinically suspected AP.

• Biomaterials Research
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• v.22 no.4
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• pp.279-289
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• 2018

Background: Cell behavior is the key to tissue regeneration. Given the fact that most of the cells used in tissue engineering are anchorage-dependent, their behavior including adhesion, growth, migration, matrix synthesis, and differentiation is related to the design of the scaffolds. Thus, characterization of the scaffolds is highly required. Micro-computed tomography (micro-CT) provides a powerful platform to analyze, visualize, and explore any portion of interest in the scaffold in a 3D fashion without cutting or destroying it with the benefit of almost no sample preparation need. Main body: This review highlights the relationship between the scaffold microstructure and cell behavior, and provides the basics of the micro-CT method. In this work, we also analyzed the original papers that were published in 2016 through a systematic search to address the need for specific improvements in the methods section of the papers including the amount of provided information from the obtained results. Conclusion: Micro-CT offers a unique microstructural analysis of biomaterials, notwithstanding the associated challenges and limitations. Future studies that will include micro-CT characterization of scaffolds should report the important details of the method, and the derived quantitative and qualitative information can be maximized.

• Journal of the Korean Geotechnical Society
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• v.39 no.8
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• pp.17-28
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• 2023

Laboratory-scale hydraulic fracturing experiments were conducted on granite specimens at various viscosities and injection rates of the fracturing fluid. A series of cross-sectional computed tomography (CT) images of fractured specimens was obtained via a three-dimensional X-ray CT imaging method. Pixel-level fracture segmentation of the CT images was conducted using a convolutional neural network (CNN)-based Nested U-Net model structure. Compared with traditional image processing methods, the CNN-based model showed a better performance in the extraction of thin and complex fractures. These extracted fractures extracted were reconstructed in three dimensions and morphologically analyzed based on their fracture volume, aperture, tortuosity, and surface roughness. The fracture volume and aperture increased with the increase in viscosity of the fracturing fluid, while the tortuosity and roughness of the fracture surface decreased. The findings also confirmed the anisotropic tortuosity and roughness of the fracture surface. In this study, a CNN-based model was used to perform accurate fracture segmentation, and quantitative analysis of hydraulic stimulated fractures was conducted successfully.

• Korean Journal of Radiology
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• v.22 no.8
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• pp.1300-1309
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• 2021

Objective: To assess the feasibility and reproducibility of pancreatic surface lobularity (PSL) quantification derived from abdominal computed tomography (CT) in a population of patients free from pancreatic disease. Materials and Methods: This retrospective study included 265 patients free from pancreatic disease who underwent contrast-enhanced abdominal CT between 2017 and 2019. A maximum of 11 individual PSL measurements were performed by two abdominal radiologists (head [5 measurements], body, and tail [3 measurements each]) using dedicated software. The influence of age, body mass index (BMI), and sex on PSL was assessed using the Pearson correlation and repeated measurements. Inter-reader agreement was assessed using the intraclass correlation coefficient (ICC) and Bland Altman (BA) plots. Results: CT images of 15 (6%) patients could not be analyzed. A total of 2750 measurements were performed in the remaining 250 patients (143 male [57%], mean age 45 years [range, 18-91]), and 2237 (81%) values were obtained in the head 951/1250 (76%), body 609/750 (81%), and tail 677/750 (90%). The mean ± standard deviation PSL was 6.53 ± 1.37. The mean PSL was significantly higher in male than in female (6.89 ± 1.30 vs. 6.06 ± 1.31, respectively, p < 0.001). PSL gradually increased with age (r = 0.32, p < 0.001) and BMI (r = 0.32, p < 0.001). Inter-reader agreement was excellent (ICC 0.82 [95% confidence interval 0.72-0.85], with a BA bias of 0.30 and 95% limits of agreement of -1.29 and 1.89). Conclusion: CT-based PSL quantification is feasible with a high success rate and inter-reader agreement in subjects free from pancreatic disease. Significant variations were observed according to sex, age, and BMI. This study provides a reference for future studies.

• Journal of radiological science and technology
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• v.47 no.3
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• pp.175-182
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• 2024

Advanced modeled iterative reconstruction (ADMIRE) represents a repetitive reconstruction method that can adjust strength and kernel, each of which are known to affect computed tomography (CT) image quality. The aim of this study was to quantitatively analyze the noise and spatial resolution of CT images according to ADMIRE control factors. Patient images were obtained by applying ADMIRE strength 2 and 3, and kernel B40 and B59. For quantitative evaluations, the noise level, spatial resolution, and overall image quality were measured using coefficient of variation (COV), edge rise distance (ERD), and natural image quality evaluation (NIQE). The superior values for the average COV, ERD, and NIQE results were obtained for the ADMIRE reconstruction conditions of ADMIRE 2 + B40, ADMIRE 3 + B59, and ADMIRE3 + B59. NIQE, which represents the overall image quality based on no-reference, was about 6.04 when using ADMIRE 3 + B59, showing the best result among the reconstructed image acquisition conditions. The results of this study indicate that the ADMIRE strength and kernel chosen for use in ADMIRE reconstruction have a significant impact on CT image quality. This highlights the importance of adjusting to the control factors in consideration of the clinical environment.