• Korean Journal of Radiology
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• v.1 no.2
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• pp.91-97
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• 2000

Objective: To determine whether the time-intensity curves acquired by test and main dose contrast injections for MR angiography are similar. Materials and Methods: In 11 patients, repeated contrast-enhanced 2D-turbo-FLASH scans with 1-sec interval were obtained. Both test and main dose timeintensity curves were acquired from the abdominal aorta, and the parameters of time-intensity curves for the test and main boluses were compared. The parameters used were arterial and venous enhancement times, arterial peak enhancement time, arteriovenous circulation time, enhancement duration and enhancement expansion ratio. Results: Between the main and test boluses, arterial and venous enhancement times and arteriovenous circulation time showed statistically significant correlation (p < 0.01), with correlation coefficients of 0.95, 0.92 and 0.98 respectively. Although the enhancement duration was definitely greater than infusion time, reasonable measurement of the end enhancement point in the main bolus was impossible. Conclusion: Only arterial and venous enhancement times and arteriovenous circulation time of the main bolus could be predicted from the test-bolus results. The use of these reliable parameters would lead to improvements in the scan timing method for MR angiography.

• Nuclear Engineering and Technology
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• v.56 no.7
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• pp.2570-2575
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• 2024

The study aims to develop a novel, lead-free, flexible and lightweight composite shielding material against ionizing radiation. For this, it was used bismuth oxide (Bi₂O₃) in RTV-2 silicon matrix. The shielding tests were carried out in both diagnostic X-ray energies and intermediate gamma-ray energy range of up to 662 keV to determine the radiation attenuation properties of this material in terms of attenuation ratio, half value layer, tenth value layer, mean free path and lead equivalency of samples in weight of 30%, 40%, 50% in Bi₂O₃. In the diagnostic X-ray energy range, half value layer, tenth value layer and lead equivalency (in mm Pb) of the produced samples were measured at 80 and 100 kVp narrow beam conditions according to the requirements of EN IEC 61331-1 standard. The results show that lead equivalent values of the produced novel sheets was measured to be 0.16 mm Pb, corresponding to a 6 mm thickness of the flexible sample when it contains 30% wt. Bi₂O₃ in RTV matrix. The experimental findings for durability and flexibility also indicated that this new RTV-based flexible, lead -free shielding composite can be used safely for especially for manufacturing aprons, garments and thyroid guards used in mammography, radiology, nuclear medicine and dental applications in practice.

• The Korean Journal of Nuclear Medicine
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• v.37 no.4
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• pp.235-244
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• 2003

Purpose: Attention deficit hyperactivity disorder (ADHD) has been known as psychiatric disorder in childhood associated with dopamine dysregulation. In present study, we investigated changes in dopamine transporter (DAT) density of the basal ganglias using I-123 N-(3-iodopropen-2-yl) -2-carbomethoxy-3beta-(4-chlorophenyl) tropane [I-123 IPT] SPECT in children with ADHD before and after methylphenidate treatment. Materials and Method: Nine drug-naive children with ADHD and seven normal children were included in the study. We peformed brain SPECT two hours after the intravenous administration of I-123 IPT and made both quantitative and qualitative analyses using the obtained SPECT data, which were reconstructed for the assessment of soecific/nonspecific DAT binding ratios in the basal ganglia. All children with ADHD reperformed [123I]IPT SPECT after treatment with methylphenidate(0.7mg/kg/d) during about 8 weeks. SPECT data reconstructed for the assessment of specific/nonspecific DAT binding ratio of the basal ganglia were compared between before and after treatment methylphenidate. We investigated correlation between the change of ADHD symptom severity assessed with ADHD rating scale-IV and specific/nonspecific DAT binding ratio of basal ganglia. Results: Children with ADHD had a significantly greater specificinonspecific DAT binding ratio of the basal ganglia comparing to normal children(Right : z = 2.057, p = 0.041 : Left : z : 2.096, p = 0.032). Under treatment with methylphenidate in all children with ADHD, specificinonspecific DAT binding ratio of both basal ganglia decreased significantly greater than before treatment with methylphenidate (Right : t = 3.239, p = 0.018 ; Left : t = 3.133, p = 0.020). However, no significant correlation between the change of ADHD symptom severity scores and specific/nonspecific DAT binding ratio of the basal ganglia were found. Conclusions: These findings support the complex dysregulation of the dopaminergic neurotransmitter system in children with ADHD.

• Investigative Magnetic Resonance Imaging
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• v.9 no.2
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• pp.101-108
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• 2005

Purpose : Early detection of small brain metastases is important. The purpose of this study was to compare the detectability of brain metastases according to the size between 1.5 T and 3.0 T MRI. Materials and Methods : We reviewed 162 patients with primary lung cancer who were examined for TNM staging. After administration of double dose of Gd-DTPA, MR imaging was performed with SPGR by 3.0 T MRI and then with T1 SE sequence by 1.5 T MRI. In each patient, three readers performed qualitative assessment. Sensitivity, positive predictive value, and diagnostic accuracy were calculated in 3.0 T and 1.5 T MRI according to size. Using the signal intensity (SI) measurements between the metastatic nodules and adjacent tissue, nodule-to-adjacent tissue SI ratio was calculated. Results : Thirty-one of 162 patients had apparent metastatic nodules in the brain at either 1.5 T or 3.0 T MR imaging. 143 nodules were detected in 3.0 T MRI, whereas 137 nodules were detected at 1.5 T MRI. Six nodules, only detected in 3.0 T MRI, were smaller than 3.0 mm in dimension. Sensitivity, positive predictive value, and diagnostic accuracy in 3.0 T MRI were 100 %, 100 %, and 100 % respectively, and in 1.5 T MRI were 95.8%, 88.3%, and 85.1% respectively. SI ratio was significantly higher in the 3.0 T MRI than 1.5 T MRI (p=0.025). Conclusion : True positive rate of 3.0 T MRI with Gd-DTPA was superior to 1.5 T MRI with Gd-DTPA in detection of metastatic nodules smaller than 3.0 mm.

• Journal of Sasang Constitutional Medicine
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• v.28 no.2
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• pp.110-122
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• 2016

Objectives The purpose of this study was to develop the Sasangin Diagnostic Questionnaire for Specialist(SDQ_S) and to evaluate the reliability and validity of SDQ_S for standardization of sasang constitutional diagnosis by korean medicine Specialist in clinical practice.Methods SDQ_S was developed through discussions of three sasang constitutional medical specialist. We recruited 210 subjects aged from 20 to 70, and conducted the evaluation of SDQ_S and sasang constitutional diagnosis. For the reliability test, internal consistency was examined by calculating the cronbach's α coefficient on 88 items excepted measurements of trunk, and independence and agreement was examined by chi-square test and McNemar test for 84 subjects which retested SDQ_S. For the validity test, discriminant functions was derived from the sample group(105 subjects), and they were applied to the test group(105 subjects). We identified the hit-ratio of SDQ_S in the test group.Results and Conclusions In the reliability test, the cronbach's α coefficient was 0.664 and 87 items(98.9%) have dependent relationships between 1st test and 2nd test. And 39 items(44.3%) have high agreements(0.8≤McNemar), 26 items(29.5%) have common agreements(0.4≤McNemar<0.8). In the validity test, four discriminant variables(Soeum Index, Taeeum Index, Torso Ratio I, Taeyang Index) were selected, and two discriminant functions were derived. Total hit-ratio was 74.2%, and hit-ratio of Taeeumin(76.7%) was higher than that of Soeumin(75.9%) and Soyangin(69.7%). SDQ_S has good reliability and validity for sasang constitutional diagnosis.

• Journal of Oral Medicine and Pain
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• v.36 no.1
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• pp.39-51
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• 2011

The aims of this study were to investigate whether the facial skeletal patterns previously reported to be related to temporomandibular disorder (TMD) in other studies could be consistently observed in the TMD patients diagnosed according to Research Diagnostic Criteria for Temporomandibular Disorder (RDC/TMD) Axis I and evaluate its usability in the orthodontic clinics to examine the patients with TMD related symptoms. The clinical records and radiographs of female patients who visited the TMD and Orofacial Pain Clinic of Seoul National University Dental Hospital and were diagnosed as TMD were consecutively filed for this study. Patients were clinically examined and diagnosed according to the revised diagnostic algorithms of RDC/TMD Axis I and the lateral cephalogram, panoramic orthopantomogram, temporomandibular joint (TMJ) orthopantomogram, and transcranial radiograph of each patient were taken and digitalized. The data of patients who were under 18 years of age or had any systemic disease, trauma history involving the TMJ, or skeletal deformity at the time of the first examination were excluded. The remaining data of 96 female patients were finally analyzed. The obtained results were as follows: 1. There are no significant differences of cephalometric measurements between RDC I (muscle disorders) diagnostic groups. 2. Only the articular angle of the RDC group IIc (disk displacement without reduction without limited opening) patients was larger than patients of the no diagnosis of RDC II group (disk displacement). 3. Larger articular angle and smaller facial height ratio were observed in RDC IIIc group (osteoarthrosis) compared to IIIa group (arthralgia). Larger articular angle, larger Bjork sum, smaller posterior facial height, and smaller facial height ratio were observed in RDC group IIIc compared to no diagnosis of RDC III group (arthralgia, arthritis, and arthrosis). 4. According to the results of cephalometric analysis in simplified RDC groups, smaller overjet was observed in muscle disorders (MD) group. Facial height ratio and IMPA were smaller and articular angle was larger in disk displacements (DD) group than in no diagnosis of DD group. In arthrosis (AR) group, posterior facial height, and facial height ratio were smaller, and articular angle, gonial angle, facial convexity, FMA, Bjork sum, and ANB were larger than in no diagnosis of AR group. In joint pain (JP) group, only posterior facial height was smaller than no diagnosis of JP group. In conclusion, Facial morphologic patterns showing posterior-rotated mandible and lower posterior facial height is related to RDC group II and III diagnosis of the TMJ in female TMD patients. RDC/TMD Axis I diagnosis can provide a good clinical diagnostic tool for the standardized examination of the TMJ in orthodontic clinics.

• Tuberculosis and Respiratory Diseases
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• v.57 no.2
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• pp.132-137
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• 2004

Background : The measurement of adenosine deaminase(ADA) level in pleural fluid is useful in the diagnosis of tuberculous(TB) pleural effusion. However, ADA is also elevated in other diseases such as malignancy, bacterial infections, empyema, and collagen vascular disease, ADA alone has limited value. The object of this study is to determine diagnostic usefulness of the combined use of ADA value with lymphocyte/neutrophil ratio(L/N ratio) rather than the use of ADA alone. Method : We evaluated 198 patients(age=$55.9{\pm}12.9$, M/F=2.7:1) with pleural effusion who had admitted in Gyeong-sang National University Hospital from Jan. 1999 to Dec. 2001. retrospectively. Patients were divided into four diagnostic groups: TB pleural effusion(n=91), parapneumonic effusion(n=65), malignant effusion(n=21), and transudative effusion(n=13). The ADA level, differential cell count, biochemistry, cytology, and microbiology of each diagnostic groups were evaluated. The sensitivity, specificity, negative predictive value(npv), positive predictive value(ppv) and efficiency were calculated at each ADA values and combined ADA value with various L/N ratios. Results : The ADA level in TB pleural effusion was significantly higher than that of parapneumonic effusion, malignant pleural effusion, and transudative effusion(p<0.05). Sensitivity, specificity, ppv, npv and efficiency at $ADA{\geqq}50$ IU/L in the diagnosis of TB pleural effusion were 89.0%, 82.2%, 81.0%, 89.8% and 85.5% respectively. When $ADA{\geqq}50$ IU/L was combined with lymphocyte/neutrophil $ratio{\geqq}0.75$, sensitivity, specificity, ppv, npv, and efficiency were 83.5%, 96.3%, 95.0%, 87.9% and 90.5% respectively. Specificity, ppv and efficiency were increased with combination of ADA value and L/N ratio. Conclusion : Combination of ADA value and L/N ratio in pleural effusion is more useful than ADA value alone in the diagnosis of TB pleural effusion.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1977-1979
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• 1999

This work characterized in terms of the physical properties of heavy elements as reduction filter in the diagnostic radiology. From the results of experimental evaluation, it was founded that in the case of the Ho filter, the variety of X-ray property with kVp was less than those of Ba, Cu and Al. And the ratio of transit-dose to surface and the load of X-ray tube were increased in the order of Al, Ba, Cu and Ho. The contrast of X-ray image showed the higher value in the order of Cu, Al, Ba and Ho.

• Journal of Chest Surgery
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• v.28 no.3
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• pp.308-312
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• 1995

A 5-year retrospective study of 14 patients with diaphragmatic injuries revealed 9 blunt and 5 penetrating injuries. In the blunt trauma group, 7 were left and 2 were right side. The penetrating diaphragmatic wound consist of 3 left and 2 right sided. Sex ratio was 11: 3, with male predominanace. Preoperative diagnosis was possible in 9 cases and delayed diagnosis [greater than 24 hours occured in 5 cases.Simple chest X-ray was diagnostic or highly suggestive in 7 cases. 7 cases were diagnosed diaphragmatic injuries by computed tomography, fiuroscopy or by explorative operation. All of the cases had association injury. 11 cases of diaphragmatic ruptures were corrected through thoracotomy and 3 cases needed exploratory laparotomy. One death occured after operation due to associated injuries and respiratory failure. Blunt and penetrating diaphragmatic injuries remain a diagnostic challenge and associated injuries, delayed diagnosis determine the outcome.

• Journal of radiological science and technology
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• v.21 no.2
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• pp.11-18
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• 1998

Single phase, narrow beam X-ray attenuation data were obtained using various construction materials concrete, white block, red block, 3 hole block, gypsum board, artificial marble, cement, plate glass, wood, and lead. Tube voltages of 60, 80, 100, 120 kVp were employed and the resulting curves were compared to transmission data found in this report. The shielding methodology and the derivation of equations used for determination of barrier requirements were presented in NCRP 49. We could calculate the X-ray exposed dose after attenuation and thickness of protection barrier in the clinic facilities accordingly. For the purpose of maximizing the benefit/cost ratio to diagnostic shielding, various construction materials must be installed carefully and attnuation rate considered thoroughly.