• Journal of the Korean Society of Radiology
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• v.82 no.5
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• pp.1246-1257
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• 2021

Purpose To assess the predictive factors and describe the imaging features of mediastinal lymph node (MLN) metastases in patients with head and neck cancer. Materials and Methods We compared the clinical features and disease characteristics (sex, age, site of primary tumor, histologic type, history of prior treatments, TNM stages, and metastasis in cervical LNs) of patients with head and neck cancers between the MLN metastasis and no MLN metastasis groups. We also evaluated the chest CT (distribution and maximum dimension of the largest LN) and PET/CT (maximum standardized uptake value) features of MLN metastases based on the MLN classification. Results Of the 470 patients with head and neck cancer, 55 (11.7%) had MLN metastasis, involving 150 mediastinal stations. Hypopharynx cancer, recurrent tumor, T4 stage, N2/N3 stages, and M1 stage were found to be significant predicting factors for MLN metastasis. The most common location of MLN metastasis was ipsilateral station 2 (upper paratracheal LNs, 36.4%), followed by ipsilateral station 11 (interlobar LNs, 27.3%) and ipsilateral station 10 (hilar LNs, 25.5%). Conclusion Metastasis to MLNs should be considered in patients with head and neck cancer, especially in cases that are associated with a hypopharyngeal cancer, recurrent tumor, and high TNM stages.

• Journal of Biomedical Engineering Research
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• v.39 no.1
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• pp.48-54
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• 2018

In this study, We developed a Ancillary device for child radiography for X-ray of children under 5 years old and verified its effectiveness. Chest X-rays of children younger than 5 years of age were performed by Supine method at the position of Table detector, Short - Source to Image Receptor Distance(SID). Existing Supine and Short -SID imaging methods cause many problems, such as errors in image reading and excessive radiation exposure dose to patients, but the use of an Ancillary device for child radiography(ADCR) solves these problems. A total of 160 children were divided into the Upright group using ADCR and Supine group without ADCR. The chest X-ray image was visually evaluated by two radiologists with reference to the European Commission's List of Quality Criteria for Diagnostic Radiographic Images in Pediatrics. The total score of the qualitative evaluation was 5.15% higher in the chest upright method using ADCR than in the chest supine method without ADCR, and the chest upright method score was higher than that of the chest supine method in items 1 to 7. whether infants have deep inspiration or not, 4.87% higher for item 1, whether infants rotate or not and the degree of tilting, 0% higher for the item 2, the reproduction of image from just above apices of lungs to T12/L1, 0% for the item 3, reproduction of the vascular pattern in central 2/3 of the lungs, 6.92% higher for the item 4, reproduction of the trachea and the proximal bronchi, 12.9% higher for the item 5, visually sharp reproduction of the diaphragm and costo-phrenic angles, 10% higher for the item 6, reproduction of the spine and paraspinal structures and visualisation of the retrocardiac lung and the mediastinum, and 3.65% higher for the item 7. Items 2 and 3 showed no statistically significant differences(P > 0.05), and items 1, 4, 5, 6, and 7 showed statistically significant differences(P < 0.05). In conclusion, Upright method using ADCR in pediatric chest X-ray is considered as a good alternative to existing Supine method.

• Imaging Science in Dentistry
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• v.44 no.4
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• pp.263-271
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• 2014

Purpose: This study aimed to evaluate the use of dental cone-beam computed tomography (CBCT) in the diagnosis of osteoporosis among menopausal and postmenopausal women by using only a CBCT viewer program. Materials and Methods: Thirty-eight menopausal and postmenopausal women who underwent dual-energy X-ray absorptiometry (DXA) examination for hip and lumbar vertebrae were scanned using CBCT (field of view: $13cm{\times}15cm;$ voxel size: 0.25 mm). Slices from the body of the mandible as well as the ramus were selected and some CBCT-derived variables, such as radiographic density (RD) as gray values, were calculated as gray values. Pearson's correlation, one-way analysis of variance (ANOVA), and accuracy (sensitivity and specificity) evaluation based on linear and logistic regression were performed to choose the variable that best correlated with the lumbar and femoral neck T-scores. Results: RD of the whole bone area of the mandible was the variable that best correlated with and predicted both the femoral neck and the lumbar vertebrae T-scores; further, Pearson's correlation coefficients were 0.5/0.6 (p value=0.037/0.009). The sensitivity, specificity, and accuracy based on the logistic regression were 50%, 88.9%, and 78.4%, respectively, for the femoral neck, and 46.2%, 91.3%, and 75%, respectively, for the lumbar vertebrae. Conclusion: Lumbar vertebrae and femoral neck osteoporosis can be predicted with high accuracy from the RD value of the body of the mandible by using a CBCT viewer program.

• The Journal of the Korea Contents Association
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• v.19 no.8
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• pp.276-283
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• 2019

The purpose of this study is to evaluate the usefulness of automatic exposure control (AEC) by analyzing entrance surface dose (ESD) and entropy on using automatic exposure and manual exposure. The experimental method was to measure the dose by placing a semiconductor dosimeter on the Rando Phantom for the Pelvis, Abdomen, Skull, and Chest regions. The DICOM file was simultaneously acquired and then entropy was analyzed by using Matlab. As a result, when using the automatic exposure control, dose of all sites was lower than manual exposure's dose and entropy was high. In addition, paired t-test was performed for each item and p<0.05 was found in each item. In conclusion, the use of automatic exposure control can be a useful method to contribute to the optimization of the exposure dose and the image quality by reducing the amount of unnecessary radiation amount and information loss that can occur in X-ray examination.

• The Korean Journal of Nuclear Medicine Technology
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• v.28 no.1
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• pp.23-29
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• 2024

Purpose: 99mTc-mebrofenin hepatobiliary scintigraphy (HBS) is an important and clinically useful diagnostic imaging study for detecting complications after liver transplantation. CT contrast agents due to their high atomic numbers, lead to a decrease in gamma ray count rates. This study investigated the impact of CT contrast agents on the uptake of 99mTc-mebrofenin in the liver. Materials and Methods: The quantitative HBS was performed on sixty-two liver transplantation patients (male:female=36:26), with a mean age of 59.4±6.4 years. Statistical comparison of hepatic uptake reduction ratio (HURR%) before and after the injection of CT contrast agents was performed using a paired t-test. Results: Hepatic uptake of the reduction ratio was 94.47±3.65% for the pre-CT contrast agents and 92.17±4.00% for the post-CT contrast agents. HURR% after CT contrast agent injection showed a statistically significant difference compared to before the injection (t=11.09, P<0.001). Conclusion: It will be necessary to pay attention when examining the HBS of patients with liver transplantation after the injection of CT contrast medium. It is advisable to schedule the examination on a different day to prevent residual contrast medium in the body from interfering with the quantitative evaluation of the nuclear medicine examination.

• Journal of Veterinary Clinics
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• v.24 no.4
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• pp.608-612
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• 2007

A 4-year-old castrated male Cocker spaniel was referred with chief complaint of pelvic limbs paralysis and trembling. This dog was diagnosed as a case of myelomalacia complicated with intervertebral disc disease(IVDD) by radiography and magnetic resonance imaging(MRI). This patient was treated by injection-AP with apitoxin, herbal medicine and moxibustion. The acupoints such as GV02-1, GV04, GV11, GV12, GV13, GV14, BL11, BL18, BL23, BL25, BL28, GB21, HT07, KI03, LI04, LU07, SI03, SI06, ST36, ST38, ST39, ST40, ST41, GB30, GB31, GB34, Liv03, SP06 and trigger points($T1{\sim}T4\;and\;T9{\sim}L1$) were used for treatment. At the session 1, the dog could not stand and move the limbs. However, gradual improvement of clinical signs was observed after 7, 14 and 21 session of treatment. Although the clinical signs related to pelvic paralysis were not completely abolished with TVM methods, this case showed the marked improvement of clinical signs after 21 sessions of treatment. In conclusion, the present patient was a case with canine myelomalacia complicated with IVDD which showed not so complete but somewhat improvement by TVM method.

• Imaging Science in Dentistry
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• v.35 no.4
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• pp.191-198
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• 2005

Purpose: To characterize the effects of 2-deoxy-D-glucose (2DG) and quercetin (QCT) on cytokine secretion of IL-6, $TGF-\beta$ and gene expression of Col I in irradiated MC3T3-E1 cells Materials and Methods: The MC3T3-El cells were cultured in an a-MEM supplemented with 5mM 2DG or 10mM QCT and then the cells were incubated 12h before irradiation with 2, 4, 6, and 8Gy X-ray using a linear accelerator delivered at a dose rate of 1.5Gy/min. Level of IL-6 and $TGF-\beta$ was determined by ELISA. Also expression of Col I was examined by RT-PCR. Results: In accordance with the radiation dose, the amount of $TGF-\beta$ was not different in RA + QCT, but it showed a peak value in control and RA + 2DG at 4Gy on the 3rd day. However, all groups showed a decreasing tendency dose-dependently in RA+QCT on the 7th day (p<0.01). In accordance with the radiation dose, the amount of IL-6 increased dose-dependently in all groups on the 3rd day. On the 7th and 21st day, all groups showed peak values at 4Gy. RA+QCT showed a slightly increased amount of IL-6 at 2Gy, but it showed a slightly decreased amount at 4, 6, and 8Gy. In accordance with the period of culture after irradiation, the expression of Col I increased dose-dependently in RA+QCT. Conclusion: The result showed that QCT acted as radiosensitizer in the secretion of $TGF-\beta$ and gene expression of Col I during differentiation in irradiated MC3T3-E1 cells at the cellular level.

• Journal of the Korean Society of Radiology
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• v.81 no.5
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• pp.1151-1163
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• 2020

Purpose This study aimed to evaluate changes of subprosthetic pannus on cardiac CT and determine its relationship to echocardiographic findings in patients with mechanical aortic valve replacement (AVR). Materials and Methods Between April 2011 and November 2017, 17 AVR patients (56.8 ± 8.9 years, 12% male) who showed pannus formation on CT and had undergone both follow-up CT and echocardiography were included. The mean interval from AVR to the date of pannus detection was 10.5 ± 7.1 years. In the initial and follow-up CT and echocardiography, the pannus extent and echocardiographic parameters were compared using paired t-tests. The relationship between the opening angle of the prosthetic valve and the pannus extent was evaluated using Pearson correlation analysis. Results The pannus extent was significantly increased on CT (p < 0.05). The peak velocity (3.9 ± 0.8 m/s vs. 4.2 ± 0.8 m/s, p = 0.03) and mean pressure gradient (36.4 ± 15.5 mm Hg vs. 42.1 ± 15.8 mm Hg, p = 0.03) were significantly increased. The mean opening angles of the mechanical aortic leaflets were slightly decreased, but there was no statistical significance (73.1 ± 8.3° vs. 69.4 ± 12.1°, p = 0.12). The opening angle of the prosthetic leaflets was inversely correlated with the pannus extent (r = -0.57, p < 0.001). Conclusion The pannus extent increases over time, increasing transvalvular peak velocity and the pressure gradient. CT can be used to evaluate the pannus extent associated with hemodynamic changes that need to be managed by surgical intervention.

• Imaging Science in Dentistry
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• v.31 no.1
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• pp.51-55
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• 2001

Purpose : This study was performed to compare the diagnostic ability of conventional intraoral radiographs with that of digital subtraction image and to assess the quantifying ability of digital subtraction image for simulated apical root resorption Materials and Methods : Conventional intraoral radiographs and digital images of ten sound maxillary central incisors and those with simulated apical root resorption were taken with varying horizontal and vertical angulations of the x-ray beam. The diagnostic accuracy to detect the lesion was evaluated on conventional intraoral radiographs and digital subtraction images by ROC analysis. The amount of simulated apical root resorption was also estimated on the reconstruction images by Emago/sup (R)/ and compared with actual amount of tooth loss using paired t-test. Results: The diagnostic accuracy of conventional intraoral radiographs to detect the apical root resorption was low (ROC area = 0.6446), and the sensitivity and the specificity of digital subtraction images were 100%, respectively. The calculated amounts of apical root resorption showed no statistically significant difference with the actual amounts of the lesion (p>0.05). Conclusion: Digital subtraction radiography is powerful tool to detect the small apical root resorption, and quantitative analysis of small amounts of the lesion can be evaluated by digital subtraction radiography.

• Imaging Science in Dentistry
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• v.42 no.3
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• pp.129-137
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• 2012

Purpose: To compare different radiographic methods for assessing endodontically treated teeth. Materials and Methods: Root canal treatments were applied in 120 extracted mandibular teeth, which were divided into four groups: (1) ideal root canal treatment (60 teeth), (2) insufficient lateral condensation (20 teeth), (3) root canals filled short of the apex (20 teeth), (4) overfilled root canal treatment (20 teeth). The teeth were imaged using intraoral film, panoramic film, digital intraoral systems (CCD and PSP), CCD obtained with portable X-ray source, digital panoramic, and CBCT images obtained at 0.3 $mm^3$ and 0.2 $mm^3$ voxel size. Images were evaluated separately by three observers, twice. Kappa coefficients were calculated. The percentage of correct readings obtained from each modality was calculated and compared using a t-test (p<0.05). Results: The intra-observer kappa for each observer ranged between 0.327 and 0.849. The inter-observer kappa for each observer for both readings ranged between 0.312 and 0.749. For the ideal root canal treatment group, CBCT with 0.2 $mm^3$ voxel images revealed the best results. For insufficient lateral condensation, the best readings were found with periapical film followed by CCD and PSP. The assessment of teeth with root canals filled short of the apex showed the highest percentage of correct readings by CBCT and CCD. For the overfilled canal treatment group, PSP images and conventional periapical film radiographs had the best scores. Conclusion: CBCT was found to be successful in the assessment of teeth with ideal root canal treatment and teeth with canals filled short of the apex.