• Korean Journal of Radiology
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• 제24권11호
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• pp.1151-1163
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• 2023

Objective: To develop a deep-learning-based bone age prediction model optimized for Korean children and adolescents and evaluate its feasibility by comparing it with a Greulich-Pyle-based deep-learning model. Materials and Methods: A convolutional neural network was trained to predict age according to the bone development shown on a hand radiograph (bone age) using 21036 hand radiographs of Korean children and adolescents without known bone development-affecting diseases/conditions obtained between 1998 and 2019 (median age [interquartile range {IQR}], 9 [7-12] years; male:female, 11794:9242) and their chronological ages as labels (Korean model). We constructed 2 separate external datasets consisting of Korean children and adolescents with healthy bone development (Institution 1: n = 343; median age [IQR], 10 [4-15] years; male: female, 183:160; Institution 2: n = 321; median age [IQR], 9 [5-14] years; male: female, 164:157) to test the model performance. The mean absolute error (MAE), root mean square error (RMSE), and proportions of bone age predictions within 6, 12, 18, and 24 months of the reference age (chronological age) were compared between the Korean model and a commercial model (VUNO Med-BoneAge version 1.1; VUNO) trained with Greulich-Pyle-based age as the label (GP-based model). Results: Compared with the GP-based model, the Korean model showed a lower RMSE (11.2 vs. 13.8 months; P = 0.004) and MAE (8.2 vs. 10.5 months; P = 0.002), a higher proportion of bone age predictions within 18 months of chronological age (88.3% vs. 82.2%; P = 0.031) for Institution 1, and a lower MAE (9.5 vs. 11.0 months; P = 0.022) and higher proportion of bone age predictions within 6 months (44.5% vs. 36.4%; P = 0.044) for Institution 2. Conclusion: The Korean model trained using the chronological ages of Korean children and adolescents without known bone development-affecting diseases/conditions as labels performed better in bone age assessment than the GP-based model in the Korean pediatric population. Further validation is required to confirm its accuracy.

• Imaging Science in Dentistry
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• 제51권4호
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• pp.421-427
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• 2021

Purpose: The pulp length to width (PL/W) ratio of the maxillary lateral incisor can be used as an age determination method. This study aimed to investigate the correlation between the PL/W ratio of the maxillary lateral incisor on panoramic radiographs and human chronological age in Indonesian subjects. Materials and Methods: This study analyzed with 134 maxillary lateral incisors on 113 panoramic radiographs from patients who visited the Oral and Maxillofacial Radiology Unit of Dental Hospital Universitas Padjadjaran, Bandung, Jawa Barat, Indonesia, from 2013 to 2018 (age range: between 11 to 60 years). The pulp length was measured from the pulp chamber roof to the apical foramen, and the pulp width was measured on the cervical area of the cementoenamel junction in millimeters using Fiji ImageJ open-source software. Simple linear regression (in SPSS) was used to analyze the results. The reliability of the observers was evaluated. Results: The PL/W ratio of the maxillary lateral incisor was significantly correlated with chronological age (P<0.01). No statistically significant difference was found in the PL/W ratio between the left and right maxillary lateral incisors(P=0.333). There was a very strong correlation (r=0.939) between the PL/W ratio of the maxillary lateral incisor and human chronological age, with the following formula: age= -3.057+1.875×PL/W ratio (R²=0.882, standard error of estimate: 4.659). Conclusion: The PL/W ratio of the maxillary lateral incisor on panoramic radiograph can be used for age determination in Indonesian subjects.

• Imaging Science in Dentistry
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• 제44권3호
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• pp.185-191
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• 2014

Purpose: This study investigated the developmental stages of third molars in relation to chronological age and compared third molar development according to location and gender. Materials and Methods: A retrospective analysis of panoramic radiographs of 2490 patients aged between 6 and 24 years was conducted, and the developmental stages of the third molars were evaluated using the modified Demirjian's classification. The mean age, standard deviation, minimal and maximal age, and percentile distributions were recorded for each stage of development. A Mann-Whitney U test was performed to test the developmental differences in the third molars between the maxillary and mandibular arches and between genders. A linear regression analysis was used for assessing the correlation between the third molar development and chronological age. Results: The developmental stages of the third molars were more advanced in the maxillary arch than the mandibular arch. Males reached the developmental stages earlier than females. The average age of the initial mineralization of the third molars was 8.57 years, and the average age at apex closure was 21.96 years. The mean age of crown completion was 14.52 and 15.04 years for the maxillary and the mandibular third molars, respectively. Conclusion: The developmental stages of the third molars clearly showed a strong correlation with age. The third molars developed earlier in the upper arch than the lower arch; further, they developed earlier in males than in females.

• Imaging Science in Dentistry
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• 제43권4호
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• pp.267-272
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• 2013

Purpose: Demirjian's dental maturity scores and curves have been widely used for human age determination. Several authors have reported considerable differences between the true and estimated age based on the Demirjian curves, which have been accounted for by ethnicity. The purpose of the current study was to assess the role of ethnicity-specific dental maturation curves in age estimation of Saudi children. Materials and Methods: A sample of 452 healthy Saudi children aged 4 to 14 years were aged based on the original French-Canadian Demirjian curves and several modified Demirjian curves specified for certain ethnic groups: Saudi, Kuwaiti, Polish, Dutch, Pakistani, and Belgian. One-way ANOVA and a post hoc Scheff$\acute{e}$'s test were used to assess the differences between chronological age and dental age estimated by the different curves (P<0.05). Results: The curves designed for Dutch, Polish, Saudi, and Belgian (5th percentile) populations had a significantly lower error in estimating age than the original French-Canadian and Belgian (50th percentile) curves. The optimal curve for males was the Saudi one, with a mean absolute difference between estimated age and chronological age of 8.6 months. For females, the optimal curve was the Polish one, with a mean absolute difference of 7.4 months. It was revealed that accurate age determination was not related to certain ethnicity-specific curves. Conclusion: We conclude that ethnicity might play a role in age determination, but not a principal one.

• Anatomy and Cell Biology
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• 제56권4호
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• pp.474-481
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• 2023

The dental characteristics created by acquired dental treatments can be used as age estimators. This pilot study aimed to analyze the correlation between the number of teeth observed for dental characteristics and chronological age and to develop new non-invasive age estimation models. Dental features on panoramic radiographs (420 radiographs of subjects aged 20-89 years) were classified and coded. The correlation between the number of teeth for each selected code (codes V, X, T, F, P, and L) and age was observed, and multiple regression was performed to analyze the relationship between them. Eleven regression models with various combinations of dental sextants were presented. The model with the data from both sides of the posterior teeth on both jaws showed the best performance (root mean square error of 14.78 years and an adjusted R² of 0.461). The model with all teeth was the second-best. Based on these results, we confirmed statistically significant correlations between certain dental features and chronological age. We also observed that some regression models performed sufficiently well to be used as adjunctive methods in forensic practice. These results provide valuable information for the design and performance of future full-scale studies.

• International Journal of Internet, Broadcasting and Communication
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• 제7권1호
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• pp.20-22
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• 2015

Recently, the study of smart phone user habits has become a highly focused topic due to the rapid growth of the smart phone market. Indeed, sequential pattern analysis methods were efficiently used for web-based user habit mining long time ago. However, by means of simulations, it has been observed that these methods might fail for smart phone-based user habit mining. In this paper, we propose a novel approach that leads to a considerably increased performance of the traditional sequential pattern analysis methods by reasonably cutting off each chronological sequence of user logs on a device into shorter ones, which represent the sequential user activities in various periods of a day.

• 성인간호학회지
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• 제20권2호
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• pp.219-230
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• 2008

Purpose: The purpose of this study was to discover the recovery process of those having had myocardial infarction. Methods: 15 participants with myocardial infarction were recruited by theoretical sampling methods. The data were retrieved through in depth interview, participant observation, and medical records of the patients. Collected data were analyzed through grounded theory approach of Strauss and Corbin(1998). Results: 63 concepts, 27 subcategories, and 11 categories were deduced from the open coding process. The recovery process of myocardial infarction showed to be a process of 'Controling healthy track', and chronological recovery process was a four-step process of recognizing disruption of healthy track, making efforts for controlling the disrupted healthy track, reconstructing the new healthy track, and adapting to the new healthy track phase. 'Controling healthy track' had three types of self-initiation, contention of reality, and fateful acceptance. Conclusion: The results provided basic information for nursing intervention strategies depending on 'Controling healthy track' process by each phase and different types.

• 대한한의학회지
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• 제35권1호
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• pp.88-98
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• 2014

Objectives: The purpose of this study is to investigate the relationship between bone age, chronological age, anthropometric parameters, and diagnosed pulse rate on child-adolescence's growth according to sex and the revelation of secondary sexual characteristics. Methods: Growth-concerned 44 children and adolescence (from 6 to 16 years) were analyzed in retrospective study. They visited Korean Medical Clinic in Suwon, Korea from January 2012 to October 2013. Individual bone age (BA), chronological age (CA), Risser sign, anthropometric parameters, and pulse rate were measured. The correlations of each variable were done by Pearson analysis, Spearman analysis and Regression analysis. Results: 1. The female group was shown to have stronger negative correlation between pulse rate and BA, CA than the male group. In gender analysis, the female group showed negative correlation between weight and pulse rate. 2. In a further analysis according to the revelation of secondary sexual characteristics, the group of child-adolescent without secondary sexual characteristics was shown to have stronger negative correlation between pulse rate and BA, CA than the group with secondary sexual characteristics. The height percentile and pulse rate were negative correlation in secondary sexual character being. 3. The Risser sign and pulse rate were not correlated in this study. Conclusions: These findings suggested that a regular and continual measurement of pulse rate is effective in estimating potential for growth in child-adolescent group.

• 대한정형외과학회지
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• 제52권1호
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• pp.73-82
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• 2017

목적: 화학요법만으로 치료한 소아 척추 결핵 환아들에서의 후만의 경시적 변화를 분석하였다. 대상 및 방법: 2세부터 15세 사이의 101명을 대상으로 하여 후향적으로 단순 방사선 영상과 소수에게서 자기공명영상을 이용하여 치료 시작 시와 치료 종결 시의 잔존 성장판에 의한 후만 변형의 변화를 살폈다. 결과: 영상상 초진 시 추간판의 완전 파괴로 판정한 예들은 경추의 경우 40명 중 2명(5.0%), 흉추 내에서는 30명 중 8예(26.7%), 그리고 요천추에서는 31명 중 6명(19.4%)이었다. 나머지 예들에서는 성장판이 완전하게 또는 부분적으로 잔존하는 것으로 판정하였다. 101명 중 후만 변형이 변치 않고 유지된 경우는 20명(19.8%), 후만각 감소 예는 14명(13.9%), 그리고 후만각의 증가 예는 67명(66.3%)에서 관찰되었다. 결론: 반수 이상의 환아에서 치료 시작 시점에서 이미 병이 심히 진행되었던 것을 알 수 있었다. 후만 변형의 진행 여부는 일차적으로 치료 시작 시점에서 예측 가능하나 그 정확도가 떨어지므로 후만 변형의 변화의 보다 정확한 증거를 확인할 수 있는 투약 종료 시점에서 실시할 것을 권한다. 진행형과 자연 교정군에서는 성장 종료 시까지의 추적 관찰이 필요하다.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제16권4호
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• pp.254-260
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• 2013

Purpose: Recently, vitamin D insufficiency has increased and has been correlated to growth and puberty in children. This study was conducted to find the prevalence of subclinical vitamin D insufficiency and its influence on school-aged children in Korea. Methods: The subjects of this study were 397 children aged 7 to 15 years who had been tested for 25-OH vitamin D3 among the outpatients of the Department of Pediatrics in Eulji General Hospital from March 2007 to February 2011. Data for age, sex, comorbidities, serum 25-OH vitamin D3, height, weight, body mass index (BMI), and sunlight exposure time were collected before and after 3 months of vitamin D administration, retrospectively. Results: Vitamin D insufficiency was present in 343 (86%) of the subjects. In the vitamin D insufficient group, chronological age was $8.96{\pm}1.72$ years, mean height (z-score [z]) was $0.51{\pm}1.26$, mean BMI (z) was $0.81{\pm}2.20$, and bone age was $10.26{\pm}1.75$ years. In the vitamin D sufficient group, chronological age was $9.61{\pm}1.77$ years, mean height (z) was -$0.66{\pm}0.98$, mean BMI (z) was -$0.01{\pm}1.16$, and bone age was $9.44{\pm}2.12$ years. A paired t-test showed that three months after vitamin D administration, the mean 25-OH vitamin D3 level in the insufficient group increased to $24.38{\pm}10.03$ ng/mL and mean BMI (z) decreased to $0.67{\pm}1.06$. Conclusion: In Korean school-aged children, vitamin D insufficiency were relatively higher and may be closely related with higher BMI. Insufficient rise of the level of vitamin D after supplementation suggest the new supplementation guidelines, especially for Korean children.