• 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 Digital Convergence
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• v.12 no.3
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• pp.367-375
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• 2014

In this thesis we observe microvascular structure in mice by using micro-computed tomography (CT), which is high-resolution X-ray imaging equipment that can acquire Real-time dynamic image, and it aims to investigate the usefulness of micro-CT developed by Institute for Radiological Imaging Science Wonkwang University School of Medicine. After acquiring the systemic images of rats, contrast-enhanced 3D images of vascular structures could be acquired by using Maximum Intensity Projection (MIP) and Volume Rending Technique (VRT), This was divided into each vascular system of head, abdomen and heart and systemic vascular system.

• Tuberculosis and Respiratory Diseases
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• v.67 no.5
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• pp.436-444
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• 2009

Background: Micro computed tomography (CT) is rapidly developing as an imaging tool, especially for mice, which have become the experimental animal of choice for many pulmonary disease studies. We evaluated the usefulness of micro CT for evaluating lung fibrosis in the murine model of bleomycin-induced lung inflammation and fibrosis. Methods: The control mice (n=10) were treated with saline. The murine model of lung fibrosis (n=60) was established by administering bleomycin intra-tracheally. Among the 70 mice, only 20 mice had successful imaging analyses. We analyzed the micro CT and pathological findings and examined the correlation between imaging scoring in micro CT and histological scoring of pulmonary inflammation or fibrosis. Results: The control group showed normal findings on micro CT. The abnormal findings on micro CT performed at 3 weeks after the administration of bleomycin were ground-glass opacity (GGO) and consolidation. At 6 weeks after bleomycin administration, micro CT showed various patterns such as GGO, consolidation, bronchiectasis, small nodules, and reticular opacity. GGO (r=0.84) and consolidation (r=0.69) on micro CT were significantly correlated with histological scoring that reflected pulmonary inflammation (p<0.05). In addition, bronchiectasis (r=0.63) and reticular opacity (r=0.83) on micro CT shown at 6 weeks after bleomycin administration correlated with histological scoring that reflected lung fibrosis (p<0.05). Conclusion: These results suggest that micro CT findings from a murine model of bleomycin-induced lung fibrosis reflect pathologic findings, and micro CT may be useful for predicting bleomycin-induced lung inflammation and fibrosis in mice.

• Journal of Chest Surgery
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• v.31 no.4
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• pp.380-387
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• 1998

We evaluated CT findings of bronchial carcinoid and accuracy of preoperative pathological diagnosis according to two subtypes. The subjects were 10 cases(typical;5, atypical;5), confirmed by surgery and tissue pathology. Sputum cytology(n=10), percutaneous aspiration(n=1) and bronchoscopic biopsy (n=8) were performed, preoperatively. The CT findings were analysed according to two subtypes. Typical carcinoid shows central location in all, and bronchial lumens just proximal to tumor were widened in two, whereas atypical carcinoid presented as peripheral leison in two. Among central atypical carcinoid, two cases showed flat meniscus appearance of lumen. Remaining one showed diffuse wall thickening. Intratumoral low density by necrosis was noted in one. Both subtypes show contrast enhancement. For preoperative diagnosis, sputum cytology & percutaneous aspiration were not conclusive at all. As for bronchoscopic biopsy, only 3 cases were accurately diagnosed as typical carcinoid. Typical carcinoid presented as endobronchial mass in all, whereas atypical carcinoid presented in various appearance. In all atypical & some typical carcinoid were misdiagnosed as primary lung cancer, preoperatively. However, in typical carcinoid, conservative surgery was possible. In conclusion, if there is discrepancy between CT findings & preoperative pathological diagnosis, full understanding of CT findings of bronchial carcinoid is imperative to choose appropriate surgical modality.

• Journal of Oral Medicine and Pain
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• v.34 no.2
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• pp.179-188
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• 2009

Aim of this study is to examine correlation between size of the coronal pulp cavity and chronological age in adult. Total 716 teeth (218 mandibular canines, 230 first premolars, 268 second premolars) free from pathologies and dental restorations were selected from 276 patients (111 males, 165 females), ranging from 20-69 years. Using periapical X-ray, the height (mm) of the crown (CH=coronal height) and the height (mm) of the coronal pulp cavity (CPCH=coronal pulp cavity height) of the teeth were measured. The tooth-coronal index (TCI) after Ikeda et al (Jpn. J. For. Med. 1985;39:244-250) was computed for each tooth and regressed on real age. With increasing age, the TCI was relatively decreased, indicating the reduction of length of the pulp chamber. Even reduction of the TCI with aging was found in combined group rather than in each sex and type of tooth separately. The most definite reduction was in canine of combined group. The correlation coefficient was strongest when measurement from canines of females (r2=0.247).

• Journal of Periodontal and Implant Science
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• v.51 no.4
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• pp.264-275
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• 2021

Purpose: Periodontitis is considered a local risk factor for medication-related osteonecrosis of the jaws (MRONJ). However, little is known about the progression of periodontitis in the presence of zoledronic acid (ZOL). The aim of this study was to evaluate the effects of the systemic use of ZOL on the progression of experimental periodontitis (EP) in rats, as ZOL could modulate the progression of periodontitis and concomitantly cause MRONJ in individuals with periodontitis. Methods: Forty-eight male Wistar rats were randomly distributed in 6 groups (n=8 each). To induce EP, ligatures were placed around the right first mandibular molars. Three groups were treated with ZOL (0.15 mg/kg/week, intraperitoneal), and 3 with 0.9% saline solution (controls). In the ZOL/Lig30 and ZOL/Lig 15 groups, after 4 weeks of treatment with ZOL, EP was induced and euthanasia was performed after 30 and 15 days of EP induction, respectively. In both groups, the animals continued to receive ZOL after EP until the end of the experiment. In the Lig/ZOL group, EP was induced first, and 15 days later, ZOL was administered for 8 weeks, with euthanasia 1 week after the last dose. After euthanasia, the mandibles were evaluated using micro-computed microtomography (micro-CT) and histomorphometry. Bone loss was measured, and the presence of osteonecrosis was evaluated histologically. The data were evaluated using the Student t-test and the Mann-Whitney test, with a significance level of 5%. Results: In the Lig/ZOL group, micro-CT revealed less alveolar bone resorption in the distal root (P<0.01) than in the control group (Lig/Con). Histomorphometric analysis confirmed less alveolar bone resorption in the Lig/ZOL group (P=0.001). Histologically, osteonecrosis was more common in the ZOL groups. Conclusion: ZOL decreased alveolar bone resorption in rats with EP. However, it presented a higher risk for MRONJ.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.445-454
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• 2019

Layered double hydroxides (LDHs) nanoparticles have emerged as novel nanomaterials for bio-imaging applications due to its unique layered structure, physicochemical properties, and good biocompatibility. Bio-imaging is one of the most important fields for medical applications in clinical diagnostics and therapeutics of various diseases. Enhanced diagnostic techniques are needed to realize new paradigm for next-generation personalized medicine through nanoscale materials. When nanotechnology is introduced into bio-imaging system, nanoparticle probes can endow imaging techniques with enhanced ability to obtain information about biological system at the molecular level. In this review, we summarize structural features of LDH nanoparticles with current issues of bio-imaging system. LDH nanoparticle probes are also discussed through in vitro as well as in vivo studies in various bio-imaging techniques including fluorescence imaging, magnetic resonance imaging (MRI), positron emission tomography (PET), and computed X-ray tomography (CT), which will have the potential in the development of the advanced nanoparticles with high sensitivity and selectivity.

• Journal of the Korean Society of Radiology
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• v.79 no.6
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• pp.303-310
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• 2018

Purpose: To evaluate the CT features of incidental breast lesions on chest CT and to suggest useful criteria for referral to a specialized breast unit. Materials and Methods: Between May 2009 and April 2014, enhanced chest CT examination reports containing the key word 'breast' were reviewed retrospectively. Patients who had incidental breast lesion and were referred to a specialized breast unit and then underwent pathological confirmation or follow-up over a 1-year period were included. Finally, 86 patients (all female, mean age, $48.9{\pm}12.6years$) were enrolled. Two radiologists evaluated lesion characteristics, including size, shape, margins, and enhancement. The correlations between the CT features and pathologies were evaluated, and the diagnostic accuracy of CT features in various combinations was assessed. Results: Among the CT features, irregular shape, non-circumscribed margin, and high contrast enhancement were different between malignant and benign lesions (p < 0.05). The combination of non-circumscribed margin and high contrast enhancement had the highest accuracy (97.7%). Conclusion: Reliable CT features for incidental malignant breast masses are irregular shape, non-circumscribed margin, and high contrast enhancement. The combination of non-circumscribed margin and high contrast enhancement could help distinguish incidental malignant breast lesions and indicate referral to a specialized breast unit.

• Korean Journal of Radiology
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• v.22 no.12
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• pp.2082-2093
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• 2021

Objective: We conducted a systematic review and meta-analysis of the tissue adequacy and complication rates of percutaneous transthoracic needle biopsy (PTNB) for molecular analysis in patients with non-small cell lung cancer (NSCLC). Materials and Methods: We performed a literature search of the OVID-MEDLINE and Embase databases to identify original studies on the tissue adequacy and complication rates of PTNB for molecular analysis in patients with NSCLC published between January 2005 and January 2020. Inverse variance and random-effects models were used to evaluate and acquire meta-analytic estimates of the outcomes. To explore heterogeneity across the studies, univariable and multivariable metaregression analyses were performed. Results: A total of 21 studies with 2232 biopsies (initial biopsy, 8 studies; rebiopsy after therapy, 13 studies) were included. The pooled rates of tissue adequacy and complications were 89.3% (95% confidence interval [CI]: 85.6%-92.6%; I² = 0.81) and 17.3% (95% CI: 12.1%-23.1%; I² = 0.89), respectively. These rates were 93.5% and 22.2% for the initial biopsies and 86.2% and 16.8% for the rebiopsies, respectively. Severe complications, including pneumothorax requiring chest tube placement and massive hemoptysis, occurred in 0.7% of the cases (95% CI: 0%-2.2%; I² = 0.67). Multivariable meta-regression analysis showed that the tissue adequacy rate was not significantly lower in studies on rebiopsies (p = 0.058). The complication rate was significantly higher in studies that preferentially included older adults (p = 0.001). Conclusion: PTNB demonstrated an average tissue adequacy rate of 89.3% for molecular analysis in patients with NSCLC, with a complication rate of 17.3%. PTNB is a generally safe and effective diagnostic procedure for obtaining tissue samples for molecular analysis in NSCLC. Rebiopsy may be performed actively with an acceptable risk of complications if clinically required.

• Korean Journal of Radiology
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• v.22 no.9
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• pp.1547-1554
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• 2021

Objective: We aimed to investigate whether repeated intravascular administration of iodinated contrast media (ICM) or gadolinium-based contrast agents (GBCAs) within a short interval was associated with an increased risk of post-contrast acute kidney injury (PC-AKI). Materials and Methods: This retrospective study included 300 patients (mean age ± standard deviation, 68.5 ± 8.1 years; 131 male and 169 female) who had undergone at least one ICM-enhanced perfusion brain CT scan, had their baseline and follow-up serum creatinine levels available, and had not undergone additional contrast-enhanced examinations 72 hours before and after a time window of interest were included. The study population was divided into three groups: single-dose group and groups of patients who had received multiple contrast administrations in the time window of interest with the minimum contrast repeat interval either within 4 hours (0-4-hour group) or between 4 to 48 hours (4-48-hour group). Multivariable logistic regression analysis was conducted to evaluate the association between AKI and repeated ICM administrations. A similar supplementary analysis was performed including both ICM and GBCA. Results: When ICM was only considered ignoring GBCA, among 300 patients, 207 patients received a single dose of ICM, 58 had repeated doses within 4 hours (0-4-hour group), and 35 patients had repeated doses between 4 to 48 hours (4-48-hour group). Most patients (> 95%) had a baseline estimated glomerular filtration rate (eGFR) of ≥ 30 mL/min/1.73 m². AKI occurred in 7.2%, 13.8%, and 8.6% of patients in the single-dose, 0-4-hour, and 4-48-hour groups, respectively. In the 0-4-hour and 4-48-hour groups, additional exposure to ICM was not associated with AKI after adjusting for comorbidities and nephrotoxic drugs (all p values > 0.05). Conclusion: Repeated intravascular administrations of ICM within a short interval did not increase the risk of AKI in our study patients suspected of acute stroke with a baseline eGFR of ≥ 30 mL/min/1.73 m².