• Imaging Science in Dentistry
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• v.44 no.4
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• pp.257-262
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• 2014

Purpose: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Materials and Methods: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., $0^{\circ}$), $+10^{\circ}$, $+12^{\circ}$, $-12^{\circ}$, and $-10^{\circ}$ with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. Results: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of $-12^{\circ}$, -0.66 to -0.11 at $-10^{\circ}$, -0.51 to +0.19 at $0^{\circ}$, -0.64 to +0.08 at $+10^{\circ}$, and -0.64 to +0.1 at $+12^{\circ}$. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Conclusion: Changing the slice orientation in the range of $-12^{\circ}$ to $+12^{\circ}$ reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.2
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• pp.230-236
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• 2008

Purpose: This study was performed to investigate the incidence, types of fracture, treatment, associated fracture and complications in patients with nasal bone fracture. Materials and methods: Clinical examination, patient's records and radiographic images were evaluated in 230 cases of nasal bone fractures who were treated at the Department of Oral and Maxillofacial Surgery, Chonnam National University Hospital for recent 5 years; from January 2002 to December 2006. Results: 1. The age of patient was ranged from 4 to 77 years (mean age=36.6 years); Males was 75.7% (n=174), and females 24.3% (n=56). 2. The cause of the nasal bone fracture in this study was a fall or slip down (28.8%, n=66), sports accident (26.0%, n=60), fighting (21.3%, n=49), traffic accident (9.6%, n=22), industrial trauma (7.8%, n=18), and the others (6.6%, n=15). 3. For the patterns of fracture, simple fracture without displacement occured in 10.4% (n=24). Simple fracture with displacement without septal bone fracture was found in 49.5% (n=114). Simple fracture with displacement in company with septal bone fracture showed in 32.6% (n=75). Commiuted fracture with severe depression was presented in 7.4% (n=17). 4. The reduction the displaced nasal bone was carried out in 2 to 10 days (mean 6.8 days) after the injury. 5. Nasal bone fracture associated with Le Fort I fracture (6.5%, n=6.5), Le Fort II fracture (7.4%, n=17), Le Fort III fracture (1.3%, n=3), NOE fracture (13.9%, n=32), ZMC fracture (17.4%, 40), maxillary bone fracture (8.3%, n=19), orbital blow-out fracture (15.7%, n=36), frontal bone fracture (1.3%, n=3) and alveolar bone fracture (10.9%, n=25). 6. The major type of treatment method was closed reduction in 90% (n=207), open reduction in 3% (n=7), and observation in 7% (n=16). 7. There were some complications such as ecchymosis, hyposmia, hypo esthesia and residual nasal deformity which are compatible. Open rhino-plasty was conducted for 3 patients who had residual nasal deformity. Conclusions: These results suggest that most of nasal bone fractures are occurred physically active aged groups(age 10-49 years) and could be treated successfully with closed reduction at 7 days after the injury.

• 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.

• Journal of Veterinary Clinics
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• v.21 no.1
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• pp.72-75
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• 2004

A ten months old, female Yorkshire terrier weighing 2.88 kg referred to veterinary leaching hospital of college of veterinary medicine, Konkuk University because of syncope, cough and dyspnea. First hematological and serum chemical test revealed thrombocytopenia, mild anemia, and increase of concentration of ALP (195 U/L). On 57 days later, second hematological and serum chemical test revealed polycythemia, increase of concentration of ALP (211 UR.), and Tchol (387 mg/dl). Right atrium enlargement, main pulmonary artery bulge and cardiomegaly (VHS = 11.5) were observed in radiographic findings. Ultrasohographic images showed both right and left ventricular dilation and turbulent flow between the descending aorta and the main pulmonary artery in color Doppler imaging. ECG showed left ventricular enlargement, SA block, and electrical alternant. Thoracotomy was performed through left fourth intercostal incision under isoflurane anesthesia. Patent ductus arteriosus was double ligated with 1-0 silk. Cough and dyspnea disappeared on 5 days after operation. Turbulent flow was not found in color doppler imaging of ultrasonography on 10 days after operation. Ten months later after the operation, syncope could not exist any more.

• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.18-22
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• 2012

This study was performed to evaluate the sensitivity of conventional film-screen radiography (CFSR) and direct digital radiography (DDR) for detection of various amounts of free peritoneal fluid. Ten adult male healthy beagles were used in this study. Radiographic examinations were performed in the right lateral and ventrodorsal positions. Fluid was injected in increments of 2.0 ml/kg of body weight up to 20.0 ml/kg of body weight. The images of CFSR and DDR were evaluated by two veterinary radiologists for evidence of abdominal fluid without knowledge of injected fluid volume. Data were evaluated by using the receiver operation curve (ROC) analysis and the area under the curve (AUC). There was no significant difference in detection of peritoneal fluid between DDR and CFSR in the ROC analysis. The accuracy of CFSR (0.805) was relatively higher than that of DDR (0.733), based on the ROC analysis and AUC. AUC of CFSR was higher in most injection doses. These results suggest that CFSR is more accurate than DDR for the detecting peritoneal fluid. Therefore, for situation in which digital radiographs are equivocal or small amount of fluid is suspected, other imaging modalities, such as ultrasonography would be helpful for determining the presence of fluids.

• Advances in pediatric surgery
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• v.16 no.2
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• pp.154-161
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• 2010

Pulmonary sequestration (PS) is a rare congenital malformation of the lower respiratory tract. The anomaly is characterized by absence of communication with the tracheobronchial tree and isolated blood supply from an anomalous systemic vessels. With the utilization of antenatal ultrasound, the diagnosis of asymptomatic neonatal PS has increased. Treatment options include observation, arterial embolization and surgical resection. The aim of the present study is to review the clinical course of PS and to share our experience with thoracoscopic resection. A total of 96 patients with PS were treated at Asan Children's Hospital between 1999 and 2010. The diagnosis of PS was established by CT in the cases managed by observation or embolization, and by tissue pathology in the surgical cases. Medical records and radiographic images were retrospectively reviewed. Thirty-nine patients were managed by embolization and 30 patients by surgery. The remaining 27 patients have been under observation without any procedures. Among 27 observation patients, 1 patient regressed completely and 10 patients were lost to follow up. Of the 39 embolizations patients, 2 had their lesion regress and sepsis was suspected after embolization. In 1 patient, the microcoil migrated to the iliac artery during the embolization procedure, and another patient developed renal abscess caused by renal artery embolization. Among 30 surgical cases, resection by thoracotomy was performed in 27 at the Department of Thoracic Surgery, and thoracoscopic resection in 3 at the Division of Pediatric Sugery. Only one wound complication ocurred. We conclud that surgical excision should be recommended for pulmonary sequestration, whether the sequestration is symptomatic or not because of the risk of infection, the low rate of natural regress, poor compliance, severe complications after embolization, and to exclude other pathology. In summary, thoracoscopic resection of the pulmonary sequestration is feasible, efficacious, safe and cosmetically superior even in neonatal period.

• Journal of radiological science and technology
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• v.21 no.1
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• pp.52-58
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• 1998

We can and must improve the diagnostic images using available knowledge and technology. At the same time we must strive to reduce the patient's integral and entrance radiation dose. Reducing the integral dose to the patient during the radiologic procedure is a primary concern of the patient, especially the pediatric patient, the radiologist and the technologist. A 100cm focal film distance generally is used for most over-table radiography. The early x-ray tubes and screen film combinations required long exposures, which often resulted in motion artifacts. But nowaday, we have the generators and x-ray tubes that can deliver the energy necessary in a very short time and the receptors that can record the information just as rapidly. And, we performed this studies to evaluate the patient exposure dose and the image quality by increasing focal film distance in diagnostic radiography. There are many factors which affected to exposure factor, but we studied to verify of FFD increase, only. Effect of increasing the focal film distance to a 140 cm distance was tested as follows; 1. The focal film distances were set at 100, 120, and 140cm. 2. A 18cm acryl(tissue equivalent) phantom was placed on the table top. 3. An Capintec 192 electrometer with PM 05 ion chamber was placed at the entrance surface of the phantom, and exposure were made at each focal film distances. 4. The procedure was repeated in the same manner as above except the ion chamber was placed beneath the phantom at the film plane. 5. Exit exposure were normalize to 8mR for each portions of the experiment. Based on the success of the empirical measurements, a detailed mathematical analysis of the dose reduction was performed using the percent depth dose data. The results of this study can be summerized as followings ; 1) Increasing FFD from 100 cm to 140 cm, we would create a situation that would have a significant effect on the overall quality of radiograph and achive the 17.42% reduction of entrance dose and the 18.95% reduction of integral dose that the patient receives. 2) Thickness of Al step wedge for equal film density increased with the long distance. 3) Increasing FFD, Magnification of image was lowered. 4) Resolution of image also increased with the FFD. As the results described above, we strongly recommend using the long FFD to provide better information for our patients and profession in abdomen radiographic studies.

• Journal of the Korean Society of Radiology
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• v.15 no.1
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• pp.21-28
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• 2021

Computed tomography (CT) has the problem of having more radiation exposure compared to other radiographic apparatus. There is a low-dose imaging technique for reducing exposure, but it has a disadvantage of increasing noise in the image. To compensate for this, various noise reduction algorithms have been developed that improve image quality while reducing the exposure dose of patients, of which the median modified Wiener filter (MMWF) algorithm that can be effectively applied to CT devices with excellent time resolution has been presented. The purpose of this study is to optimize the mask size of MMWF algorithm and to see the excellence of noise reduction of MMWF algorithm for existing algorithms. After applying the MMWF algorithm with each mask sizes set from the MASH phantom abdominal images acquired using the MATLAB program, which includes Gaussian noise added, and compared the values of root mean square error (RMSE), peak signal-to-noise ratio (PSNR), coefficient correlation (CC), and universal image quality index (UQI). The results showed that RMSE value was the lowest and PSNR, CC and UQI values were the highest in the 5 x 5 mask size. In addition, comparing Gaussian filter, median filter, Wiener filter, and MMWF with RMSE, PSNR, CC, and UQI by applying the optimized mask size. As a result, the most improved RMSE, PSNR, CC, and UQI values were showed in MMWF algorithms.

• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.2
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• pp.131-139
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• 2022

This study aimed to evaluate the effectiveness of deep convolutional neural networks (CNNs) for diagnosis of interproximal caries in pediatric intraoral radiographs. A total of 500 intraoral radiographic images of first and second primary molars were used for the study. A CNN model (Resnet 50) was applied for the detection of proximal caries. The diagnostic accuracy, sensitivity, specificity, receiver operating characteristic (ROC) curve, and area under ROC curve (AUC) were calculated on the test dataset. The diagnostic accuracy was 0.84, sensitivity was 0.74, and specificity was 0.94. The trained CNN algorithm achieved AUC of 0.86. The diagnostic CNN model for pediatric intraoral radiographs showed good performance with high accuracy. Deep learning can assist dentists in diagnosis of proximal caries lesions in pediatric intraoral radiographs.

• Journal of the korean academy of Pediatric Dentistry
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• v.48 no.4
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• pp.449-459
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• 2021

This study retrospectively analyzed the effect of clinical factors on the outcomes of REP(regenerative endodontic procedure). Patients who received the REP using triple antibiotic paste due to trauma or fracture of dens evaginatus from February, 2011 to January, 2020 were included in the study. Finally, 57 teeth in 54 patients were selected. Investigated clinical factors were as follows: intentional bleeding, etiology, and root development stage. Treatment outcomes evaluated were as follows: improvement of subjective symptoms, changes in the periapical lesion, and the amounts of root development after REP. To compensate for differences in angulation and position between repeated radiographic examinations, images were aligned by Turboreg plugin. To evaluate the amounts of root development, apical diameter, root area, and root length were measured by ImageJ software. Among the aforementioned factors, intentional bleeding had no significant effect on treatment results. Regarding the etiology, the increase in the root area and the root length was significantly less in trauma cases than in dens evaginatus fracture cases. Considering root development stage, more immature teeth presented more increase in the root area.