• Journal of Veterinary Science
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• v.24 no.4
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• pp.50.1-50.6
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• 2023

This paper reports the clinical findings and surgical treatment of feline right patent ductus arteriosus (RPDA) with a left aortic arch. A two-month-old female Maine Coon was referred for an investigation of regurgitation after weaning. RPDA with a left aortic arch was diagnosed based on the echocardiographic and computed tomography (CT) findings. A right-fourth intercostal thoracotomy was found to be an appropriate approach to the duct. Preoperative diagnosis is crucial and diagnostic imaging, including radiography, echocardiography, and cardiac CT examination, is essential for determining if the aortic arch is right or left.

• Anatomy and Cell Biology
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• v.56 no.1
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• pp.86-93
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• 2023

Age at death estimation has always been a crucial yet challenging part of identification process in forensic field. The use of human skeletons have long been explored using the principle of macro and micro-architecture change in correlation with increasing age. The clavicle is recommended as the best candidate for accurate age estimation because of its accessibility, time to maturation and minimal effect from weight. Our study applies pre-trained convolutional neural network in order to achieve the most accurate and cost effective age estimation model using clavicular bone. The total of 988 clavicles of Thai population with known age and sex were radiographed using Kodak 9000 Extra-oral Imaging System. The radiographs then went through preprocessing protocol which include region of interest selection and quality assessment. Additional samples were generated using generative adversarial network. The total clavicular images used in this study were 3,999 which were then separated into training and test set, and the test set were subsequently categorized into 7 age groups. GoogLeNet was modified at two layers and fine tuned the parameters. The highest validation accuracy was 89.02% but the test set achieved only 30% accuracy. Our results show that the use of medial clavicular radiographs has a potential in the field of age at death estimation, thus, further study is recommended.

• Journal of radiological science and technology
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• v.33 no.2
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• pp.109-120
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• 2010

The purpose of this study was first to analyze the utilization of dental examination through questionnaire to develop a diagnostic reference level of patient doses for dental radiography in korea. 77 dental institutions were classified into three groups: A group for the dental hospitals of the college of dentistry (11 institutions), B group for dental hospitals (30 institutions) and C group for dental clinics (36 institutions). The results were as follows : The mean numbers of unit chairs and medical staffs were 140.2, 15.3 and 5.8 sets, 112.6, 7.3 and 1.7 dentists, 3.1, 0.5 and no one radiologic technologists, and 19.7, 12.5 and 3.3 dental hygienists in A, B and C groups, respectively. The mean numbers of dental X-ray equipments were 14.64, 3.21 and 2.19 in A, B and C groups, respectively. Intraoral dental X-ray unit was used the most, the following equipments were panoramic, cephalometric, and cone-beam CT units. The most used X-ray imaging system was also digital system (above 50%) in all three groups. Insight dental film (Kodak, USA) having high sensitivity was routinely used for periapical radiography. The automatic processor was not used in many dental institutions, but the film-holding device was used in many dental institutions. The utilization rates of PACS in A, B and C groups were 90.9%, 83.3% and 16.7% respectively, and the PACS software program was used the most PiView STAR (Infinitt, Korea). The annual mean number of radiographic cases in one dental institution in 2008 for A group was 6.8 times and 21.2 times more than those for B and C groups, and periapical and panoramic radiographs were taken mostly. Tube voltage (kVp) and tube current (mA) for periapical radiography were similar in all three groups, but exposure time in C group was 12.0 times and 3.5 times longer than those in B and C groups. The amount of radiation exposure in C group, in which dental hygienists take dental radiographs, was more than those in other groups. The exposure parameters for panoramic radiography were similar in all three groups. In conclusion, the exposure parameters in dental radiography should be determined with reference level, not past experiences. Use of automatic processor and film-holding devices reduces the radiation exposure in film system. The quality assurance of dental equipments are necessary for the reduction of the patient dose and the improvement of X-ray image quality.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.4
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• pp.587-597
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• 2004

Over the past 20 years, great strides have been made in research regarding the mechanisms involved in the progression of carious lesions, but new equipment and research tools need to be developed to continue these advancements in caries research. Various methods have been applied to reduce the incidence of carious lesions, which have led to a significant decrease in the number of occlusal caries, but a concurrent increase in the proportion of proximal carious lesions. New diagnostic equipment has been developed to detect early stage carious lesions, and these have demonstrated excellent laboratory results and show promise in clinical applications. The research presented here examines the efficacy of the newly developed $DIFOTI^{TM}$ system in detecting proximal carious lesions compared to traditional intraoral exam and bitewing radiography, possible problems or deficiencies of using the system in clinic, possible improvements that can be made to the system, and the efficacy of detecting early, reversible carious lesions that can be remineralized by preventative fluoride applications. The subject pool consisted of 23 grammer school age patients just prior to entering the mixed dentition phase. Each patient was given a thorough oral examination, radiographic examination consisting of bitewing radiographs of the posterior teeth, and $DIFOTI^{TM}$ examination of the anterior and posterior teeth. Each examination was carried out two times by two examiners, and the data were statistically analyzed. The results are as follows: 1. The mean alpha value of reliability test of the visual oral examination was as follows; occlusal surface was 0.8470. mesial surface was 0.6430, distal surface was 0.5727. lingual surface was 0.2807 and distal surface was 0.2339. When the examination was limited to posterior teeth, the mean alpha value was as follows; occlusal surface was 0.8577, distal surface was 0.8211, lingual surface was 0.7728, buccal surface was 0.7152 and mesial surface was 0.6782. 2. The alpha value of reliability test of the radiographic analysis of carious lesions of the occlusal, mesial, and distal surfaces was 0.8500. 3. The alpha value of reliability test of the $DIFOTI^{TM}$ diagnostic analysis of carious lesions of the occlusal, buccal, lingual, mesial, and distal surfaces was determined to be 0.7917. 4. The $DIFOTI^{TM}$ diagnostic system was found to be the most accurate means of detecting occlusal, buccal, and lingual surface carious lesions (p<0.05), while mesial and distal proximal carious lesions were most accurately assessed using bitewing radiography (p<0.05).

• Journal of Veterinary Clinics
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• v.26 no.4
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• pp.367-370
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• 2009

A 5-year-old, intact female Shih-Tzu dog was presented with 1 year history of icterus, ascites and anorexia. The serum biochemistry revealed elevated liver enzyme levels. Microhepatica and decreased serosal detail were detected in abdominal radiography. Abdominal ultrasonographic findings included irregular liver margins, multifocal hypoechoic nodules in the liver parenchyma, and ascites. Computed tomography (CT) showed multifocal hypodense nodules with ring-like contrast enhancement. Cytologic and histopathologic examination by liver core biopsy revealed fibrosis. Cirrhosis was diagnosed based on above results. This report focuses on the imaging characteristics of ultrasonography and CT for liver cirrhosis in a dog.

• Imaging Science in Dentistry
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• v.40 no.2
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• pp.69-74
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• 2010

Purpose : The research was performed to predict the three dimensional relationship between the impacted mesiodens and the maxillary central incisors and the proximity with the anatomic structures by comparing their panoramic images with the CT images. Materials and Methods : Among the patients visiting Seoul National University Dental Hospital from April 2003 to July 2007, those with mesiodens were selected (154 mesiodens of 120 patients). The numbers, shapes, orientation and positional relationship of mesiodens with maxillary central incisors were investigated in the panoramic images. The proximity with the anatomical structures and complications were investigated in the CT images as well. Results : The sex ratio (M : F) was 2.28 : 1 and the mean number of mesiodens per one patient was 1.28. Conical shape was 84.4% and inverted orientation was 51.9%. There were more cases of anatomical structures encroachment, especially on the nasal floor and nasopalatine duct, when the mesiodens was not superimposed with the central incisor. There were, however, many cases of the nasopalatine duct encroachment when the mesiodens was superimpoised with the apical 1/3 of central incisor (52.6%). Delayed eruption (55.6%), crown rotation (66.7%) and crown resorption (100%) were observed when the mesiodens was superimposed with the crown of the central incisor. Conclusion : It is possible to predict three dimensional relationship between the impacted mesiodens and the maxillary central incisors in the panoramic images, but more details should be confirmed by the CT images when necessary.

• Journal of the Korean Society of Radiology
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• v.10 no.8
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• pp.619-627
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• 2016

The purpose of this study is to investigate the effect of CT contrast agent and MRI contrast agent on the area dose in the body when using automatic exposure control system in general radiography. After making rectangular holes in the center of the abdominal thickness paraffin phantom, CT contrast agent and MRI contrast agent were respectively diluted with physiological saline solution for contrast medium dilution ratio of 10:0, 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9, 0:10%. Each experiment was set to 78 kVp, 320 mA, which is the proper condition for KUB photography, and thereafter a total of 30 inspections were made for each dilution ratio using an automatic exposure control device, and the area dose corresponding to the dilution ratio of each contrast agent, Average comparison and correlation analysis were performed on the exposure index. As a result, the CT contrast agent and the MRI contrast agent appeared different in area dose according to the dilution ratio(p<0.05), and as the dilution ratio increased, the area dose increased for CT contrast agent and MRI contrast agent(P<0.05). In each test, the exposure index showed the manufacturer's recommendation of 200-800 EI value, and the exposure index and area dose increased as the area dose increased(p<0.05). In conclusion, CT contrast agent and MRI contrast agent confirmed to increase the area dose by general imaging test using all automatic exposure control device. Therefore, it is considered that it is necessary to perform it after the contrast medium has been excreted sufficiently when using usual imaging test after using the contrast agent in CT and MRI examination.

• Journal of Veterinary Clinics
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• v.25 no.2
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• pp.131-135
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• 2008

A 5-year-old Chihuahua dog was evaluated for a tetraparesis. The dog was presented with a non-ambulatory tetraparesis and neck pain. Radiography demonstrated an atlantoaxial (AA) subluxation and increased distance between the dorsal arch of the C1 and the dorsal spinous process of the C2. The AA joint was fixed with ventral transarticular fixation using two screws under fluoroscopic guidance. Neck brace was applied during 3 weeks post-operation. After 4 weeks, the dog was fully ambulatory with improved neurological function. Postoperative radiographs confirmed reduction of the luxation and no migration of screws. The dog showed complete resolution of clinical signs without signs of recurrence till 4 months after operation. Proper angulations of screws provided under fluoroscopic guidance, enabled adequate stabilization of the AA joints using ventral transarticular screw fixation which improved neurologic outcome of the patient.

• Tuberculosis and Respiratory Diseases
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• v.56 no.2
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• pp.216-220
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• 2004

Because a cavitary pulmonary metastasis is rare, it may not be readily identified. However, various types of cancers can metastasize to the lung in the form of cavities. We report a case of a multiple cavitary metastases to the lung from a cholangiocarcinoma in a 60-year-old man. He complained of generalized weakness and a poor oral intake for 2 months. The plain chest radiography and the chest computed tomography showed multiple small thick-walled cavities and nodules the both lungs. A bronchoscopic examination revealed a focal irregularly elevated surface of the mucosa at the orifice of the superior segment of the right lower lobe and the biopsy demonstrated an infiltrative metastatic adenocarcinoma. The abdomen-pelvis computed tomography showed an ill-marginated and irregularly low-dense area in the right lobe of the liver and a diffuse dilatation of the peripheral intrahepatic bile ducts. The esophagogastroscopy and colonoscopy showed no abnormal findings. It was concluded that the cholangiocarcinoma of the liver metastasized to the lung in the form of cavities. Thereafter, the patient underwent six cycles of the systemic chemotherapy with gemcitabine and cisplatin, and the follow-up imaging studies showed a partial response.

• Journal of Veterinary Clinics
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• v.23 no.2
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• pp.96-101
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• 2006

Four dogs with neurologic dysfunction resulted from intracranial hemorrhage by head trauma were referred to Veterinary Medical Teaching Hospital, Chungnam National University. There were no remarkable findings in survey radiography in four cases. CT and MRI scans were diagnostic in these cases. Three dogs underwent CT scanning. On CT images, the lesion was hyperdense and was not enhanced after intravenous contrast administration in dog 1 and dog 2. On CT of dog 4, there was no significant finding. All of four dogs were verified by dorsal, sagittal, and transverse T1-weighted (T1W) and T2-weighted (T2W) images. Appearance of the lesions in dog 1 and dog 2 was isointense (dog 2) or isointense with hyperintense rim (dog 1) on T1W images and hyperintense on T2W images. In dog 3 and dog 4, there were hypointense and hyperintense lesions on T1Wand T2W images respectively. The lesions in four dogs were located in the left intracerebral region, intracerebral and cerebellovestibular region, subdural space, and right cerebral hemisphere, respectively.