• Imaging Science in Dentistry
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• v.38 no.4
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• pp.209-213
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• 2008

Purpose : To evaluate the relative diagnostic accuracy of panoramic radiography and Water's projection in maxillary sinus inflammatory diseases by comparing the radiodensities of the images with those of CT. Materials and Methods : Panoramic radiographs, Waters' projection, and CT images from 55 subjects (11O sinuses) were included in this retrospective study. The radiodensity of each maxillary sinus in panoramic radiography was recorded separately as upper and lower divided horizontally by hard palate. In Waters' projection, the overall sinus radiodensity was recorded. The CT images were considered as gold standard. Results : In panoramic radiography, 83 sinuses had same upper and lower radiodensity and 72 of these were consistent with those of CT, 26 sinuses had different upper and lower radiodensity and 15 of these, upper radiodensity was consistent with CT, the remaining 11, lower radiodensity was consistent with CT. One sinus had upper radiolucency with lower radiopacity and both were consistent with those of CT. Altogether 73 (66.4%) among 110 sinuses in panoramic radiography showed full agreement with CT, 26 (23.6%) showed partial agreement with CT. 9 sinuses had no lower image under the hard palate in panoramic radiography due to the smaller size of sinus. In Waters' projection, the radiodensity of 105 sinuses (95.5%) were consistent with that of CT. Conclusion : The panoramic radiography showed 90.0% of the sinus conditions fully or partially which may appear less accurate than that of Water's view (95.5%) but with more detailed information of the inferior part of sinuses. (Korean J Oral Maxillofac Radiol 2008; 38 : 209-13)

• Restorative Dentistry and Endodontics
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• v.38 no.3
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• pp.146-153
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• 2013

Objectives: Aluminum step wedge (ASW) equivalent radiodensity (eRD) has been used to quantify restorative material's radiodensity. The aim of this study was to evaluate the effects of image acquisition control (IAC) of a digital X-ray system on the radiodensity quantification under different exposure time settings. Materials and Methods: Three 1-mm thick restorative material samples with various opacities were prepared. Samples were radiographed alongside an ASW using one of three digital radiographic modes (linear mapping (L), nonlinear mapping (N), and nonlinear mapping and automatic exposure control activated (E)) under 3 exposure time settings (underexposure, normal-exposure, and overexposure). The ASW eRD of restorative materials, attenuation coefficients and contrasts of ASW, and the correlation coefficient of linear relationship between logarithms of gray-scale value and thicknesses of ASW were compared under 9 conditions. Results: The ASW eRD measurements of restorative materials by three digital radiographic modes were statistically different (p = 0.049) but clinically similar. The relationship between logarithms of background corrected grey scale value and thickness of ASW was highly linear but attenuation coefficients and contrasts varied significantly among 3 radiographic modes. Varying exposure times did not affect ASW eRD significantly. Conclusions: Even though different digital radiographic modes induced large variation on attenuation of coefficient and contrast of ASW, E mode improved diagnostic quality of the image significantly under the underexposure condition by improving contrasts, while maintaining ASW eRDs of restorative materials similar. Under the condition of this study, underexposure time may be acceptable clinically with digital X-ray system using automatic gain control that reduces radiation exposure for patient.

• Journal of Korean Neurosurgical Society
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• v.49 no.5
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• pp.267-272
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• 2011

Objective : Although iliac crest autograft is the gold standard for lumbar fusion, the morbidity of donor site leads us to find an alternatives to replace autologous bone graft. Ceramic-based synthetic bone grafts such as hydroxyapatite (HA) and b-tricalcium phosphate (b-TCP) provide scaffolds similar to those of autologous bone, are plentiful and inexpensive, and are not associated with donor morbidity. The present report describes the use of Polybone$^{(R)}$ (Kyungwon Medical, Korea), a beta-tricalcium phosphate, for lumbar posterolateral fusion and assesses clinical and radiological efficacy as a graft material. Methods : This study retrospectively analyzed data from 32 patients (11 men, 21 women) who underwent posterolateral fusion (PLF) using PolyBone$^{(R)}$ from January to August, 2008. Back and leg pain were assessed using a Numeric Rating Scale (NRS), and clinical outcome was assessed using the Oswestry Disability Index (ODI). Serial radiological X-ray follow up were done at 1, 3, 6 12 month. A computed tomography (CT) scan was done in 12 month. Radiological fusion was assessed using simple anterior-posterior (AP) X-rays and computed tomography (CT). The changes of radiodensity of fusion mass showed on the X-ray image were analyzed into 4 stages to assess PLF status. Results : The mean NRS scores for leg pain and back pain decreased over 12 months postoperatively, from 8.0 to 1.0 and from 6.7 to 1.7, respectively. The mean ODI score also decreased from 60.5 to 17.7. X-rays and CT showed that 25 cases had stage IV fusion bridges at 12 months postoperatively (83.3% success). The radiodensity of fusion mass on X-ray AP image significantly changed at 1 and 6 months. Conclusion: The present results indicate that the use of a mixture of local autologous bone and PolyBone$^{(R)}$ results in fusion rates comparable to those using autologous bone and has the advantage of reduced morbidity. In addition, the graft radiodensity ratio significantly changed at postoperative 1 and 6 months, possibly reflecting the inflammatory response and stabilization.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.21 no.2
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• pp.405-413
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• 1991

The authors observed a 33-year-old male patient who had suffered from osteopetrosis with maxillary osteomyelitis. The obtained results were as follows: 1. Physical examination revealed hepatosplenomegaly and bowing legs. 2. Nearly all bones of the entire skeleton showed unusual increased radiodensity and the paranasal sinuses were markedly obliterated. 3. There were seveal old fractured sites in the femur and hip bones and subluxation of hip joint. 4. The radiodensity of both jaws were prominently increased and there were many malformed teeth and impacted teeth. 5. Bone scan revealed multiple, irregularly increased uptakes in large joints and long bones.

• Korean Journal of Veterinary Research
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• v.58 no.2
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• pp.99-101
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• 2018

A 5-year-old intact female Persian cat was referred with anorexia and vomiting. Physical examination revealed icterus in the pinna, oral mucosa, and sclera. Ultrasonography revealed several findings including uniformly hyperechoic hepatic parenchyma compared to adjacent falciform fat, increased attenuation of the ultrasound beam, and poor visualization of intrahepatic vessel borders. Computed tomography revealed hypoattenuation of the hepatic parenchyma with a radiodensity value of -60 Hounsfield units. The adjacent intrahepatic vessels appeared hyperattenuated relative to the hepatic parenchyma as if the vessels were contrast-enhanced. Based on ultrasonography and computed tomography results, the cat was tentatively diagnosed as feline hepatic lipidosis.

• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.19-26
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• 1997

Odontodysplasia is a rare developmental anomaly of tooth formation in which hard tissue are affected. Odontodyplasia affects the primary and permanent dentitions in the maxilla, mandible, or both jaws. The maxilla is involved twice as often as the mandible. The condition is more common in female than in male patients and in the anterior than in the posterior regions. The clinical manifestation of odontodysplasia are hypoplasia and hypocalcification of the enamel and dentin of affected teeth. Teeth tend to be small and discolored, with short roots and widely open pulp canal. Delayed eruption of affected teeth with abscess formation is common. Radiographically teeth assume a faint radiolucent image ("ghost teeth"). enamel and dentin appear thin and are similar in radiodensity. The pulp chambers are often larger than normal, calcifications(pulp stone and denticle) are found within them. The etiology of regional odontodysplasia is unknown. However, several causes have been discussed, including somatic mutation, local circulatory disorders, local trauma, failure of migration and differentiation of neural crest cells, local infection.

• The Korean Journal of Nuclear Medicine
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• v.3 no.1
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• pp.59-67
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• 1969

Correlation between the blood clearance half time and findings of liver scan using the colloidal radiogold in patients of liver cirrhosis is observed through the scoring system, in which the more changes in size, shape and density in the liver scan, the more points are given (table 1). Results: 1) Within the increase in severity of hepatocellular dysfunction in liver cirrhosis, the degree and frequency of following changes in liver scan (done with colloidal radiogold) were increased in order. a) generalized hepatomegaly b) enlargement of the left lobe & reduction of the right lobe c) relatively increased radiodensity in the left lobe and 4) visualization of spleen. 2) Frequency of the normal scan in liver cirrhosis was $12{\pm}3.56%$, frequency of normal value in blood clearance half time of the radiogold was $5.0{\pm}2.34%$ and frequency of normal scan & normal blood clearance rate in liver cirrhosis was $3.6{\pm}2.06%$.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.38 no.1
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• pp.44-49
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• 2012

Introduction: Sialolithes are initiated by localized deposition of calcified material in the salivary glands. And that may even cause various symptom especially swelling and pain. This study purposes to collect statistical data of sialolithiasis for clinical analysis. Materials and Methods: Among forty seven patients who have visited Seoul National University Dental Hospital during 2004-2009, patients' age, sex, location and size of stone, radiodensity of stone, symptom, surgical procedure were investigated. Statistical correlation between size, location, symptom was evaluated. Chemical composition was analyzed for 3 sialolithes. Results: The average age was 41.4 years. Sialolithiasis had slight female predilection (57.4%). Most cases occurred in the submandibular glands (91.5%). And most cases had radiopaque features (95.8%). The average size was 7.17 mm. The most frequent location of the stones were the duct orifice and the submandibular gland hilum (16 cases in each), followed by the middle part of the duct (n=8), the intraglandular area (n=4), and the proximal part of the duct (n=3). Eleven cases were asymptomatic. Thirty six cases had complaints of pain, swelling, hardness, and decrease in saliva flow (multiple symptoms). Various methods of surgery was performed. Two cases were self-removed. Thirty seven cases underwent procedure involving stone removal alone. Six cases underwent gland extirpation, and two cases underwent ductoplasty. Conclusion: There was no statistical correlation between size, location, and symptoms. Sialolith was composed of Ca (58.5-69.3%), P (30.7-35.7%), organic material, and trace inorganic material.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.5
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• pp.343-350
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• 2017

The aim of this study is to introduce a surgical technique that can maintain blood supply to prevent condylar resorption in the extracorporeal reduction of condylar fracture. Neither the medial pterygoid muscle on the ramal bone nor the lateral pterygoid muscle on the condylar fragment was detached after vertical ramal osteotomy. Thus, reduction was performed in the intracorporeal state. Therefore, blood supply was expected to be maintained to the fragments of both the condylar and ramal bones. On postoperative radiographs, the anatomical outline of the fractured condyle was well restored, and the occlusion was stable. In the unilateral case, there were no signs of mandibular condylar resorption until postoperative 3 weeks. In the 2 bilateral cases, condylar displacements with plate fractures and screw loosening were observed at postoperative 1 month or 5 months, but radiodensity at the displaced fracture site increased during the follow-up period. Finally, complete remodeling of the condylar fragments with restored anatomic appearance was observed on 8-month or 2-year follow-up radiographs. All cases exhibited good healing aspects with no signs or symptoms of mandibular condylar dysfunction during the postoperative remodeling period after intracorporeal reduction of condylar fracture.

• The Korean Journal of Nuclear Medicine
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• v.4 no.2
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• pp.41-53
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• 1970

Although the radioisotope liver scan has primarily been of use in the detection of the intra-hepatic space occupying lesions, there has been an increasing awareness of its use in evaluation of liver function. In this study, the degree of hepatomegaly, changes in shape and mottling radiodensity on each lobe and splenic visualization in the liver scans done with colloidal radiogold were numerically expressed as scores under the arbitrary standard in 210 patients with liver cirrhosis. The clinical value of this scoring system was studied with special regards to the correlation between the radiogold hepatic uptake half time and conventional liver function tests. Following were the results; 1) The normal scan appeared in 6.7% of 210 patients with liver cirrhosis. 2) The colloidal radiogold hepatic uptake half time was abnormally and progressively prolonged in parallel to severity of hepatocellular dysfunction. The mean hepatic uptake half time in cirrhosis showing normal scan was $2.76{\pm}0.73$ minutes. 3) The scoring system was well correlated with the serum albumin and globulin levels, A/G ratio and BSP retention. There was some correlative tendency in alkaline phosphatase activity. 4) There was no correlation with the thymol turbidity test, cholesterol levels, transaminase activities and bilirubin levels. 5) The spleen was visualized in 38.6% of total patients with liver cirrhosis. Excluding normal scans in liver cirrhosis, the spleen was visualized in 41.3%. 6) The scoring system appears to confirm the clinical diagnosis and to give a reliable estimate of the degree of hepatocellular dysfunction in patients with liver cirrhosis.