• Journal of the Korean Society of Radiology
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• v.14 no.1
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• pp.31-37
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• 2020

This study was conducted to examine the kinds and the frequency of incorrect outcomes occurring depending examiners' skills, in testing osteoporosis by using Dual Energy X-ray Absorptiometry(DXA) and improve frequently occurring errors by educating them. The results of an analysis show that the outcomes from the test of hips in patients with wrong postures or some regions with pressure fracture and degenerative changes were often included, even though they should be excluded, and that surgical instruments were also included in the analysis, though they should be excluded from resulting values. Of them, the errors most often found were those about patients' postures (n=56, 6 cases for spines and 50 cases for hips), followed by those about analytical processes (n=37, 35 cases for spines and 2 cases for hips), and then those about regions of interest (n=33, 28 cases for spines and 5 cases for hips). There were, however, no errors caused by the defectiveness of quality control.

• Journal of Korean Foot and Ankle Society
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• v.7 no.2
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• pp.151-156
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• 2003

Purpose: Proximal crescentic metatarsal osteotomy(PMO) is one of the most common procedures for correcting moderate to severe degree hallux valgus deformity. Although screw fixation is used for osteotomy site stability, loss of reduction can occur. The purpose of this study is to compare the sagittal plane stability of the conventional crescentic PMO fixed with a single screw with that of the crescentic PMO fixed with 1 screw and 2 supplemental K -wires. Material and Methods: Ten matched pairs of cadaveric foot specimens were used for the proximal crescentic metatarsal osteotomy. For one foot specimen of each pair, crescentic osteotomy was fixed with 4mm long threaded cannulated screw, while the matched pair was prepared by adding two axial 1.6mm K-wires to the conventionally fixed 4mm screw. The extensometer was used to measure the osteotomy gap as the metatarsal head was loaded continuously until failure using a servohydraulic MTS Mini Bionix test frame. The strength of fixation was normalized with the bone mineral density (BMD) of the paired specimen $(N{\times}cm^{2}/gm)$, Result: The average strength of the crescentic PMO with axial K-wire fixation ($458.8cm^{2}/gm$, S.D. 434.3) was significantly higher than the standard crescentic PMO ($367.5cm^{2}/gm$, S.D. 397,9) (p=0.05). Conclusion: Supplemental fixation with two axial K-wires can be added to the crescentic PMO to enhance the initial fixation stability to prevent the loss of reduction or dorsal malunion.

• Journal of radiological science and technology
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• v.36 no.1
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• pp.19-24
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• 2013

The measurement of Korea people's Radial-terminal region were frequently measure of the left hand of Radial-terminal region due to the most Korean's are right-handed and it occasionally showed incorrect results. Therefore, in this study, we accessed a correlation with error of measurement and reduced the measurement error invalid. We reviewed 50 adults patients, from March 2012 for a certain period of time, visited the orthopedic center for the neutral position of forearm of plain radiography and measured the left side of the distal radial-terminal region containing the terminal region of the right distal radius. Then we have compared and analysed both T-score. As a result, the lower value of left wrist were 45 out of 75 which is approximately 60% of left wrist group while the lower value of right wrist were 30 out of 75 which is approximately 40% of right wrist group.

• Journal of the Korean Society of Radiology
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• v.17 no.1
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• pp.115-122
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• 2023

The hip joint device is an important immobilization device for internal rotation in the diagnosis of bone density test, microfracture, and arthritis. These fixing mechanisms have limitations in maintaining reproducibility due to the use of Velcro. In this study, we developed an improved hip joint device and evaluated its usefulness. For 30 students enrolled in the Department of Radiology, we evaluated the reproducibility through medical imaging and the time required for positioning by applying the conventionaling and improved device. Changes over time were also evaluated. As a result, compared to the conventional device, the improved device showed a 32% reduction in positioning time and improved reproducibility by about 6.2 times. As for the amount of change over time, the positioning time increased in the conventional device, but decreased in the improved device, and the reproducibility of the conventional device was lower than that of the improved device. Through this, it can be said that the use of the improved device improved the image quality and reduced the radiologist's workload.

• The Journal of Advanced Prosthodontics
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• v.16 no.2
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• pp.91-104
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• 2024

PURPOSE. The objectives of the current study were to estimate the influence of self-reinforced hollow structures with a graded density on the dimensional accuracy, weight, and mechanical properties of Co-Cr objects printed with the direct metal laser sintering (DMLS) technique. MATERIALS AND METHODS. Sixty-five dog-bone samples were manufactured to evaluate the dimensional accuracy of printing, weight, and tensile properties of DMLS printed Co-Cr. They were divided into Group 1 (control) (n = 5), Group 2, 3, and 4 with incorporated hollow structures based on (spherical, elliptical, and diamond) shapes; they were subdivided into subgroups (n = 5) according to the volumetric reduction (10%, 15%, 20% and 25%). Radiographic imaging and microscopic analysis of the fractographs were conducted to validate the created geometries; the dimensional accuracy, weight, yield tensile strength, and modulus of elasticity were calculated. The data were estimated by one-way ANOVA and Duncan's tests at P < .05. RESULTS. The accuracy test showed an insignificant difference in the x, y, z directions in all printed groups. The weight was significantly reduced proportionally to the reduced volume fraction. The yield strength and elastic modulus of the control group and Group 2 at 10% volume reduction were comparable and significantly higher than the other subgroups. CONCLUSION. The printing accuracy was not affected by the presence or type of the hollow geometry. The weight of Group 2 at 10% reduction was significantly lower than that of the control group. The yield strength and elastic modulus of the Group 2 at a 10% reduction showed means equivalent to the compact objects and were significantly higher than other subgroups.

• Journal of Technologic Dentistry
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• v.30 no.1
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• pp.25-31
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• 2008

Cp-Ti and Ti-6Al-4V alloys commonly used dental implant materials, particularly for orthopaedic and osteosynthesis because of its suitable mechanical properties and excellent biocompatibility. This alloys have excellent corrosion behavior in the clinical environment. The first factor to decide the success of dental implantation is sufficient osseointegration and high corrosion resistance between on implant fixture and its surrounding bone tissue. In this study, in order to increase corrosion resistance and biocompatibility of Cp-Ti and Ti-6Al-4V alloy that surface of manufactured alloy was coated with TiN by RF-magnetron sputtering method. The electrochemical behavior of TiN coated Cp-Ti and Ti-6Al-4V alloy were investigated using potentiodynamic (EG&G Co, PARSTAT 2273. USA) and potentiostatic test (250mV) in 0.9% NaCl solution at 36.5 $\pm$ 1$^{\circ}C$. These results are as follows : 1. From the microstructure analysis, Cp-Ti showed the acicular structure of $\alpha$-phase and Ti-6Al-4V showed the micro-acicular structure of ${\alpha}+{\beta}$ phase. 2. From the potentiodynamic test, Ecorr value of Cp-Ti and Ti-6Al-4V alloys showed -702.48mV and -319.87mV, respectively. Ti-6Al-4V alloy value was higher than Cp-Ti alloy. 3. From the analysis of TiN and coated layer, TIN coated surface showed columnar structure with 800 nm thickness. 4. The corrosion resistance of TiN coated Cp-Ti and Ti-6Al-4V alloys were higher than those of the non-coated Ti alloys in 0.9% NaCl solution from potentiodynamic test, indicating better protective effect. 5. The passivation current density of TiN coated Cp-Ti and Ti-6Al-4V alloys were smaller than that of the noncoated implant fixture in 0.9% NaCl solution, indicating the good protective effect resulting from more compact and homogeneous layer formation.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.12 no.1
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• pp.14-22
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• 2012

Objectives: This study was performed to review clinical manifestations of hyperphenylalaninemia patients in Korean. Methods: 178 cases of hyperphenyalaninemia were diagnosed at department of pediatrics, Soonchunhyang University Hospital from January, 1983 to August. We reviewed DNA analysis, MR imaging, EEG, radiography of the left hand and wrist, bone densitometry (BMD), IQ test of hyperphenyalaninemia patients. Results: Out of 178 cases, 161 cases were diagnosed classic phenylketonuria and 17 cases were diagnosed BH4 deficiency. 122 cases performed DNA analysis. R243Q (10.3%), Y204C (9.9%), and IVS4-1G>A (8.1%) mutations were predominant. 22 cases underwent MR imaging. Varying degrees of symmetrical high signal intensity were noted on T2-weighted sequences in the periventricular deep white matter of 15 cases. 23 cases were performed EEG. 12 cases (52.3%) showed abnormal pattern. EEG abnormalities showed in 11 cases. On lumbar BMD four of 11 cases (36%) showed reduced bone density of more than 1 S.D. in four of 11 cases, bone age was less than chronological age by at least one year. 18 cases were performed IQ test. Mean IQ scores was $84{\pm}21.6$. Among older than 15 years (9 cases), Mean IQ scores was $72{\pm}21.2$. PTPS deficiency was 14 cases, DHPR deficiency was 2 cases, and GTPCH deficiency was 1 case. Conclusion: We confirmed there were varieties of DNA mutations. And MR imaging and EEG were nonspecific in PKU patients. Older children showed lower IQ score. Low phenylalanine diet prevents brain damage in PKU patient. Not only first few years of life but also lifetime, Keeping low phenylalanine diet is important.

• Radiation Oncology Journal
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• v.27 no.1
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• pp.15-22
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• 2009

Purpose: This study was designed to evaluate the effects on bone mineral density (BMD) and related factors according to the distance from the radiation field at different sites. This study was conducted on patients with uterine cervical cancer who received pelvic radiotherapy. Materials and Methods: We selected 96 patients with cervical cancer who underwent determination of BMD from November 2002 to December 2006 after pelvic radiotherapy at Kosin University Gospel Hospital. The T-score and Z-score for the first lumbar spine (L1), fourth lumbar spine (L4) and femur neck (F) were analyzed to determine the difference in BMD among the sites by the use of ANOVA and the post-hoc test. The study subjects were evaluated for age, body weight, body mass index (BMI), post-radiotherapy follow-up duration, intracavitary radiotherapy (ICR) and hormonal replacement therapy (HRT). Association between the characteristics of the study subjects and T-score for each site was evaluated by the use of Pearson's correlation and multiple regression analysis. Results: The average T-score for all ages was -1.94 for the L1, -0.42 for the L4 and -0.53 for the F. The average Z-score for all ages was -1.11 for the L1, -0.40 for the L4 and -0.48 for the F. The T-score and Z-score for the L4 and F were significantly different from the scores for the L1 (p<0.05). There was no significant difference between the L4 and F. Results for patients younger than 60 years were the same as for all ages. Age and ICR were negatively correlated and body weight and HRT were positively correlated with the T-score for all sites (p<0.05). BMI was positively correlated with the T-score for the L4 and F (p<0.05). Based on the use of multiple regression analysis, age was negatively associated with the T-score for the L1 and F and was positively correlated for the L4 (p<0.05). Body weight was positively associated with the T-score for all sites (p<0.05). ICR was negatively associated with the T-score for the L1 (p<0.05). HRT was positively associated with the T-score for the L4 and F (p<0.05). Conclusion: The T-score and Z-score for the L4 and F were significantly higher than the scores for the L1, a finding in contrast to some previous studies on normal women. It was thought that radiation could partly influence BMD because of a higher T-score and Z-score for sites around the radiotherapy field. We suggest that a further long-term study is necessary to determine the clinical significance of these findings, which will influence the diagnosis of osteoporosis based on BMD in patients with cervical cancer who have received radiotherapy.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.25-31
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• 2008

Purpose : This study was conducted to understand for the diagnostic discordance of bone mineral density(BMD) in DEXA(Dual Energy X-ray Absorptiometry). And the diagnostic difference between lumbar spine and femur neck, forearm was evaluated using T-score. Materials and Methods : We studied 220 females measured BMD on lumbar spine, and femur neck, forearm including ward's triangle and ultra digital(UD). We were distinguished T-score into normal, osteopenia, osteoporosis(WHO classification) and evaluated discordance rate according to age and degree of bone loss. Correlation analysis and chi-square test between L-spine, L-4, femur neck, Ward, Forearm, UD were carried out. Results : In the lumbar spine, the number of normal were in 57(25.9%), osteopenia in 86(39.1%), osteoporosis in 77(35.0%). In the L-4 and ward's triangle, the number of osteoporosis were in 78(35.5%), in 126(57.3%). There was significant correlation between lumbar, femur neck and forearm BMD in all cases. The discordance of BMD between lumbar and femur were 57%, lumbar and forearm 43%, forearm and femur 51%. The discordance rates of normal, osteopenic, osteoporotic groups were 39%, 64%, 43%, respectively, showing the highest discordance rate in osteopenia patients. In normal group of lumbar spine, the discordance rate was 25%, 23%, 11%, 65%, 86% in 30', 40', 50', 60', 70', respectively. In osteopenia, osteoporosis group of lumbar spine, the discordance rate was 62%, 55%, 36%, 20%, 9% in 30', 40', 50', 60', 70', respectively. Conclusion : It was different of the results of BMD with lumbar, femur and forearm site. The discordance rate was decreased with age in osteopenia, osteoporosis lumbar spine. In osteopenia group, the discordance rate was the highest. So, it is necessary that the BMD of lumbar, femur neck and forearm should be checked.

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.4
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• pp.292-298
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• 2012

Purpose: The purpose of this study is to ascertain the stability of the implant by comparing the effects of the change of implant diameter, length and design on implant stability quotient. Materials and methods: To remove the variable due to the difference of bone quality, the uniform density (0.48 g/$cm^3$) Polyuretane foam blocks (Sawbones$^{(R)}$, Pacific Research Laboratories Inc, Vashon, Washington) were used. Implants (Implantium$^{(R)}$, Dentium, Seoul, Korea) were placed with varying diameters (${\phi}3.8$, ${\phi}4.3$ and ${\phi}4.8$) and length (8 mm, 10 mm and 12 mm), to assess the effect on implant stability index (ISQ). Also the influence of the design of the submerged and the non-submerged (SimplelineII$^{(R)}$, Dentium, Seoul, Korea) on ISQ was evaluated. To exclude the influence of insertion torque, a total of 60 implants (n = 10) were placed with same torque to 35 N. Using Osstell$^{TM}$ mentor (Integration Diagnostic AB, Sweden) ISQ values were recorded after measuring the resonant frequency, one-way ANOVA and Tukey HSD test results were analyzed. (${\alpha}$=0.05). Results: 1. The change of the diameter of the implant did not affect the ISQ (P>.05), but the increase of implant length increased the ISQ(P<.001). 2. The change in implant design were correlated with the ISQ, and the ISQ of submerged design was significantly higher than that of the non-submerged design(P<.05). Conclusion: In order to increase implant stability, the longer implant is better to be selected, and on the same length of implant, submerged design is thought to be able to get a higher ISQ than the non-submerged.