• Imaging Science in Dentistry
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• v.37 no.2
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• pp.93-102
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• 2007

Purpose: Cone beam computed tomography (CBCT) provides a lower dose and cost alternative to conventional CT, promising to revolutionize the practice of oral and maxillofacial radiology. The purpose of this study was to evaluate the absorbed and effective doses of Implagraphy and VCT (Vatech Co., Hwasung, Korea) and compare them with those of panoramic radiography. Materials and Methods: Thermoluminescent dosimeter (TLD) chips were placed at 27 sites throughout the layers of Female ART Head and Neck Phantom for dosimetry. Implagraphy, VCT units, and Planmeca Proline XC panoramic unit were used for radiation exposures. Radiation weighted doses and effective doses were measured and calculated using 1990 and 2005 ICRP tissue weighting factors. Results: Effective doses in Sv (ICRP 2005, ICRP 1990) were 90.19, 61.62 for Implagraphy at maxillay molar area, 123.20, 90.02 for Implagraphy at mandibular molar area, 183.55, 139.26 for VCT and 40.92, 27.16 for panoramic radiography. Conclusion: Effective doses for VCT and Implagraphy were only about 2.2 to 4.5 times greater than those for panoramic radiography. VCT and Implagraphy, CBCT machines recently developed in Korea, showed moderately low effective doses.

• Imaging Science in Dentistry
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• v.51 no.4
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• pp.351-361
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• 2021

Purpose: The clivus is a region in the anterior section of the occipital bone that is commonly imaged on large-volume cone-beam computed tomography (CBCT). There have been several reports of incidental clivus variations and certain pathological entities that have been attributed to the variations. This study aimed to evaluate the effects of these variations within the scope of dentistry. Materials and Methods: Medical databases (PubMed, Scopus, and Web of Science) were searched using a controlled vocabulary (clival anomalies, cone-beam CT, canalis basilaris medianus, fossa navicularis magna, clival variation). The search was limited to English language, humans, and studies published in the last 25 years. The articles were exported into RefWorks^® and duplicates were removed. The remaining articles were screened and reviewed for supporting information on variations of the clivus on CBCT imaging. Results: Canalis basilaris medianus and fossa navicularis magna were the most common anomalies noted. Many of these variations were asymptomatic, with most patients unaware of the anomaly. In certain cases, associated pathologies ranged from developmental (Tornwaldt cyst), to acquired (recurrent meningitis). While no distinct pathognomonic aspects were noted, there were unique patterns of radiographic diagnosis and treatment modalities. Most patients had a normal course of follow-up. Conclusion: Interpretation of CBCT volumes is a skill every dentist must possess. When reviewing large-volume CBCT scans, the clinician should be able to distinguish pathology from normal anatomic variations within the skull base. The majority of clivus variations are asymptomatic and will remain undetected unless incidentally noted on radiographic examinations.

• Korean Journal of Radiology
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• v.25 no.6
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• pp.518-539
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• 2024

Coronary computed tomography angiography (CCTA) has emerged as a pivotal tool for diagnosing and risk-stratifying patients with suspected coronary artery disease (CAD). Recent advancements in image analysis and artificial intelligence (AI) techniques have enabled the comprehensive quantitative analysis of coronary atherosclerosis. Fully quantitative assessments of coronary stenosis and lumen attenuation have improved the accuracy of assessing stenosis severity and predicting hemodynamically significant lesions. In addition to stenosis evaluation, quantitative plaque analysis plays a crucial role in predicting and monitoring CAD progression. Studies have demonstrated that the quantitative assessment of plaque subtypes based on CT attenuation provides a nuanced understanding of plaque characteristics and their association with cardiovascular events. Quantitative analysis of serial CCTA scans offers a unique perspective on the impact of medical therapies on plaque modification. However, challenges such as time-intensive analyses and variability in software platforms still need to be addressed for broader clinical implementation. The paradigm of CCTA has shifted towards comprehensive quantitative plaque analysis facilitated by technological advancements. As these methods continue to evolve, their integration into routine clinical practice has the potential to enhance risk assessment and guide individualized patient management. This article reviews the evolving landscape of quantitative plaque analysis in CCTA and explores its applications and limitations.

• The Journal of Korean Society for Radiation Therapy
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• v.25 no.2
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• pp.175-180
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• 2013

Purpose: Modern radiation therapy technique such as IGRT has become a routine clinical practice on LINAC for decrease patient's set-up error. CBCT can be used to adjust patient set-up error and treat patient more accurately. The Purpose of this study is to evaluate field size of CBCT for improving Image quality and suggest reference date of CBCT field size. Materials and Methods: Image date were acquired using KV CBCT and Catphan phantom (Half fan and full fan mode were scanned from 2 ~16 cm, at intervals of 2 cm). Field size were categorized by Small field size (2 cm, 4 cm), Medium field size (8 cm, 10 cm), Large field size (more than 14 cm) and evaluate. To estimated the CTDi using CTDi phantom and Ion chamber. Results: CT number linearity of Small and Large field size are greater than Medium field size. Spatial resolution are not significantly different without Small field size. But half fan mode is more different than full fan mode. In full fan, except Medium field size, all field size exceed recommendation for HU uniformity. But half pan has stability for all field except Small field size. CTDi makes radical sign function graph in Medium field size. Conclusion: The worst result was given by Small field size for Image quality and practically. Medium field size can be useful to prevent patient from radiation exposure and give better Image quality. So this study recommends that Medium field size (8~10 cm) is more suitable for CBCT.

• Journal of Periodontal and Implant Science
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• v.47 no.2
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• pp.77-85
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• 2017

Purpose: Guided bone regeneration (GBR) is the most widely used technique to regenerate and augment bones. Even though augmented bones (ABs) have been examined histologically in many studies, few studies have been conducted to examine the biological potential of these bones and the healing dynamics following their use. Moreover, whether the bone obtained from the GBR procedure possesses the same functions as the existing autogenous bone is uncertain. In particular, little attention has been paid to the regenerative ability of GBR bone. Therefore, the present study histologically evaluated the regenerative capacity of AB in the occlusive space of a rat guided bone augmentation (GBA) model. Methods: The calvaria of 30 rats were exposed, and plastic caps were placed on the right of the calvaria in 10 of the 30 rats. After a 12-week healing phase, critical-sized calvarial bone defects (diameter: 5.0 mm) were trephined into the dorsal parietal bone on the left of the calvaria. Bone particles were harvested from the AB or the cortical bone (CB) using a bone scraper and transplanted into the critical defects. Results: The newly generated bone at the defects' edge was evaluated using micro-computed tomography (micro-CT) and histological sections. In the micro-CT analysis, the radiopacity in both the augmented and the CB groups remained high throughout the observational period. In the histological analysis, the closure rate of the CB was significantly higher than in the AB group. The numbers of cells positive for runt-related transcription factor 2 (Runx2) and tartrate-resistant acid phosphatase (TRAP) in the AB group were larger than in the CB group. Conclusions: The regenerative capacity of AB in the occlusive space of the rat GBA model was confirmed. Within the limitations of this study, the regenerative ability of the AB particulate transplant was inferior to that of the CB particulate transplant.

• Journal of radiological science and technology
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• v.26 no.1
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• pp.83-89
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• 2003

The accurate measurement of the femoral anteversion is very important to the practice of orthopedic and osteotomy. It is measured by means of the axis of head and neck of the femur and the knee axis. At the present time, widely used computed tomography method of measuring anteversion on femoral necks of patients. Measurement by the manual method and image viewer of computed tomography to determine the anteversion of femoral head were carried out on both femurs. In September and October 2002, 5 patients 28 to 36 years of age were randomly selected from Seoul National University Hospital. The purpose of this paper was to introduce a new method to measure femoral anteversion angle utilizing PACS image viewer program in the MR imaging. Significant difference was observed between the right and left side the image viewer measurement of femoral anteversion. In conclusion, MR imaging very usefulness in the measured the angle of the femoral anteversion.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.114-118
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• 2009

Sialolithiasis is the formation of calcific concretions within the ductal system of major or minor salivary glands. The submandibular gland is most involved because of its high viscosity of the saliva and the long, curved duct. It may occur at any age but, it is most common in middle-aged adults and rare in childhood. Clinical symptoms in sialolithiasis are variable but, swelling is the most common, followed by the pain. Clinical examination and radiographic examination(panoramic and mandibular occlusal radiographs, sialography, intraoral-, extraoral- ultrasound, CT scan, MRI and sialoendoscopy) can help to confirm a diagnosis and localize a stone. The treatment is surgical intervention, either removal of the sialolith or sialoadenectomy. However, non-invasive techniques including shock-wave lithotripsy, $CO_2$ laser and endoscopic treatment used in selected cases. A 5-Year-old girl referred from private practice for evaluation of a yellowish mass on the floor of the mouth. She complained that it had became three times bigger than four months ago when it was found for the first time and she had some pain on submandibular gland area occasionally. On physical examination, a firm and yellowish mass could be seen at the orifice of the submandibular duct. Diagnosis is the submandibular sialolithiasis in the anterior Wharton`s duct. Under local anesthesia, stone was removed.

• Nutrition Research and Practice
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• v.7 no.1
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• pp.43-48
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• 2013

Quantities as well as distributions of adipose tissue (AT) are significantly related to cardiovascular disease (CVD) risk factors and can be altered with caloric restriction. This study investigated which cross-sectional slice location of AT is most strongly correlated with changes in CVD risk factors after caloric restriction in obese Korean women. Thirty-three obese pre-menopausal Korean women ($32.4{\pm}8.5$ yrs, BMI $27.1{\pm}2.3\;kg/m^2$) participated in a 12 weeks caloric restriction program. Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were measured using computed tomography (CT) scans at the sites of L2-L3, L3-L4, and L4-L5. Fasting serum levels of glucose, insulin, triglyceride, total cholesterol (TC), low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), leptin and homeostasis model assessment-insulin resistance (HOMA-IR) were observed. Pearson's partial correlation coefficients were used to assess the relationship between AT measurement sites and changes in CVD risk factors after calorie restriction. When calories were reduced by 350 kcal/day for 12 weeks, body weight (-2.7%), body fat mass (-8.2%), and waist circumference (-5.8%) all decreased (P < 0.05). In addition, following caloric restriction, serum levels of glucose (-4.6%), TC (-6.2%), LDL-C (-5.3%), leptin (-17.6%) and HOMA-IR (-18.2%) decreased significantly (P < 0.05) as well. Changes in VAT at the level of L3-L4 were significantly greater than those at other abdominal sites, and these changes were correlated with changes in TC (P < 0.05), LDL-C (P < 0.001), SBP (P < 0.001) and HOMA-IR (P < 0.01). These results show that VAT at L3-L4 had a stronger correlation with CVD risk factors than with other AT measurement sites after caloric restriction.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.122-126
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• 2011

Introduction: In the lateral window approach for a maxillary sinus bone graft, there has been considerable controversy regarding the placement of a barrier membrane over the osteotomy site. In particular, when there is no damage to the Schneiderian membrane, clinicians should decide whether to use a barrier membrane or not, considering the benefits and costs. This study presents the clinical cases to demonstrate that only repositioning the detached window can lead to satisfactory bony healing of the grafted material without using a barrier membrane in the lateral approach for a maxillary sinus bone graft. Materials and Methods: Five consecutive patients were treated with the same surgical procedures. After performing the antrostomy on the lateral maxillary wall using a round carbide bur and diamond bur, the bony window was detached by a gentle levering action. After confirming no perforation of the Schneiderian membrane, the grafting procedure was carried out the detached window of the lateral maxillary wall was repositioned over the grafted material without using a barrier membrane. A gross examination was carried out at the postoperative 6 month re-entry, and the the preoperative and postoperative dental computed tomography (CT) at re-entry were compared. Results: All the procedures in the 5 patients went on to uneventful healing with no complications associated with the bone graft. Satisfactory bone regeneration without the interference of fibrous tissue on the gap between the repositioned window and lateral wall of the maxillary sinus was observed in the postoperative 6 month re-entry. The CT findings at re-entry revealed the, reconstruction of the external cortical plate including repositioned bony window. In addition, the loss of the discontinuity of the lateral maxillary wall was confirmed. Conclusion: This preliminary report showed that the detached window, which was just repositioned on the grafted material, could function as a barrier membrane in the lateral approach for a maxillary sinus bone graft. Therefore additional morphometric and histologic studies will be needed.

• Journal of radiological science and technology
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• v.35 no.2
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• pp.125-132
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• 2012

In this study a group of experts and clinical radiological technologists were surveyed to evaluate the clinical importance of current subjects in the radiological sciences. For the data collection and analysis, an open-ended questionnaire was distributed to the group of experts, and a multiple choice questionnaire was distributed to radiological technologists. Subjects were classified into 9 groups for analysis of the importance of subjects, and in regard to the questionnaire design for measurement of variables, departments and type of hospital were set up as independent variables, and the 9 groups of subjects were set up as dependent variables. As a result, clinical radiological technologists perceived Diagnostic Imaging Technology and practical courses, including general radiography, CT and MRI, as the most clinically necessary subjects, and the group of experts placed most weight on basic courses for the major. The result of this study suggests that the curriculum should be revised in a way that combines theory and practice in order to foster radiological technologists capable of adapting to the rapidly changing healthcare environment.