• Nuclear Medicine and Molecular Imaging
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• v.42 no.6
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• pp.456-463
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• 2008

Purpose: We evaluated the incidence and malignant risk of focal breast lesions incidentally detected by $^{18}F-FDG$ PET/CT. Various PET/CT findings of the breast lesions were also analyzed to improve the differentiation between benign from malignant focal breast lesions. Materials & Methods: The subjects were 3,768 consecutive $^{18}F-FDG$ PET/CT exams performed in adult females without a history of breast cancer. A focal breast lesion was defined as a focal $^{18}F-FDG$ uptake or a focal nodular lesion on CT image irrespective of $^{18}F-FDG$ uptake in the breasts. The maximum SUV and CT pattern of focal breast lesions were evaluated, and were compared with final diagnosis. Results: The incidence of focal breast lesions on PET/CT in adult female subjects was 1.4% (58 lesions in 53 subjects). In finally confirmed 53 lesions of 48 subjects, 11 lesions of 8 subjects (20.8%) were proven to be malignant. When the PET/CT patterns suggesting benignancy (maximum attenuation value>75 HU or <30HU; standard deviation of mean attenuation > 20) were added as diagnostic criteria of PET/CT to differentiate benign from malignant breast lesions along with maximum SUV, the area under ROC curve of PET/CT was significantly increased compared with maximum SUV alone ($0.680{\pm}0.093$ vs. $0.786{\pm}0.076$, p<0.05). Conclusion: The malignant risk of focal breast lesions incidentally found on $^{18}F-FDG$ PET/CT is not low, deserving further diagnostic confirmation. Image interpretation considering both $^{18}F-FDG$ uptake and PET/CT pattern may be helpful to improve the differentiation from malignant and benign focal breast lesion.

• Journal of Preventive Medicine and Public Health
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• v.29 no.3 s.54
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• pp.539-553
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• 1996

The study was conducted from May to September in 1994 to investigate applicability of the Hearing Handicap Inventory for the Elderly-Screening version(HHIE-S) in parallel with the pure-tone audiometer to the initial screening test of noise-induced hearing loss(NIHL) in some noise-exposed workers. Subjects were selected by systemic sampling that took every 10th person from 6, 700 workers taking the annual occupational health examination by the department of Health Maintenance of Dongsan Hospital Keimyung University in Taegu. The authors administered the pure-tone audiometric test and self-reported questionnaire of HHIE-S including items of sociodemographic and job-related variables concurrently. The final subjects analysed were 1,019(488 males and 531 females) excluding fourteen persons who had many missing values in their questionnaires. The reliability coefficients of HHIE-S scale by Cronbach's alpha were 0.84. In the univariate analysis of hearing handicap measured by the HHIE-S, work duration, military service and the hearing threshold loss at 1KHz and 4KHz by the initial audiometer were significant in males while age, work duration and hearing threshold loss at 1KHz and 4KHz were significant in females. In the stepwise linear regression analysis, hearing threshold loss at 1KHz and 4KHz, was the only selected variable explaining the hearing handicap in males and hearing threshold loss at 1KHz and 4KHz, age, and work duration were selected in females. In ROC curves for HHIE-S scores against NIHL as gold standard which was defined by the follow-up audiogram as more than 30dB of the average of 0.5/1/2KHz and 50dB at 4KHz, the optimal cutoff for the parallel HHIE-S appeared to be 8. The results suggest that HHIE-S appeared to have some reliability and validity in this data and might be used in screening NIHL in parallel with pure-tone audiometer in noise-exposed workers.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.4
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• pp.285-291
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• 2008

Purpose: Although automatic quantification software of myocardial perfusion SPECT provides highly objective and reproducible quantitative measurements, there is still some limitation in the direct use of quantitative measurements. In this study we derived parameters using normal variation of perfusion measurements, and tried to test the usefulness of these parameters. Materials and Methods: In order to calculate normal variation of perfusion measurements on myocardial perfusion SPECT, 55 patients (M:F = 28:27) of low-likelihood for coronary artery disease were enrolled and $^{201}TI$ rest/$^{99m}Tc$-MIBI stress SPECT studies were performed. Using 20-segment model, mean (m) and standard deviation (SD) of perfusion were calculated in each segment. As a myocardial viability assessment group, another 48 patients with known coronary artery disease, who underwent coronary artery bypass graft surgery (CABG) were enrolled. $^{201}TI$ rest/$^{99m}Tc$-MIBI stress / $^{201}TI$ 24-hr delayed SPECT was performed before CABG and SPECT was followed up 3 months after CABG. From the preoperative 24-hr delayed SPECT, $Q_{delay}$ (perfusion measurement), ${\Delta}_{delay}$ ($Q_{delay}$ - m) and $Z_{delay}$ (($Q_{delay}$ - m)/SD) were defined and diagnostic performances of them for myocardial viability were evaluated using area under curve (AUC) on receiver operating characteristic (ROC) curve analysis. Results: Segmental perfusion measurements showed considerable normal variations among segments. In men, the lowest segmental perfusion measurement was $51.8{\pm}6.5$ and the highest segmental perfusion was $87.0{\pm}5.9$, and they are $58.7{\pm}8.1$ and $87.3{\pm}6.0$, respectively in women. In the viability assessment $Q_{delay}$ showed AUC of 0.633, while those for ${\Delta}_{delay}$ and $Z_{delay}$ were 0.735 and 0.716, respectively. The AUCs of ${\Delta}_{delay}$ and $Z_{delay}$ were significantly higher than that of $Q_{delay}$ (p = 0.001 and 0.018, respectively). The diagnostic performance of ${\Delta}_{delay}$, which showed highest AUC, was 85% of sensitivity and 53% of specificity at the optimal cutoff of -24.7. Conclusion: On automatic quantification of myocardial perfusion SPECT, the normal variation of perfusion measurements were considerable among segments. In the viability assessment, the parameters considering normal variation showed better diagnostic performance than the direct perfusion measurement. This study suggests that consideration of normal variation is important in the analysis of measurements on quantitative myocardial perfusion SPECT.

• The Journal of the Korea Contents Association
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• v.16 no.6
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• pp.225-235
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• 2016

This study aims at developing Reminiscence Function Scale-Short Form(RFS-S) and verifying it as a supplemental diagnosis instrument to judge differences between normal and mild cognitive impairment and useful measure to rate effects of reminiscence therapy in the clinical field through internal consistency reliability and criterion validity. The study also aims at figuring out factors affection reminiscence function by figuring out demographic features of RFS-S. The research subjects were the control group of 60 normal people and experimental group of 58 people with mild cognitive impairment and both groups were over 65 years old. For internal consistency reliability(Cronbach's alpha) between questions was reliable with 0.63. Convergent validities of RFS-S with SRT and CDR-SB were 0.20(p<.05) and -0.25(p<.001), respectively, as both showed significant correlations. As a result of criterion validity to analyze AUROC, it was 0.68(p<.001) and less accurate. Its optimal cut-off points were 17 and sensitivity according to them was 0.59, and specificity was 0.72, respectively. However, reminiscence function according to demographic variables did not show any significant differences. Therefore, it is expected that RFS-S will be used as a supplemental diagnosis instrument with higher reliability and validity for discerning differences between normal and mild cognitive impairment and as a useful one to verify effects of reminiscence therapy.

• The Korean Journal of Nuclear Medicine
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• v.39 no.4
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• pp.231-238
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• 2005

Purpose: We investigated prospectively whether the interpretation considering the patterns of FDG uptake and the findings of unenhanced CT for attenuation correction can improve the diagnostic accuracy for assessing malignant lymph node (LN) and N stage in non-small cell lung cancor (NSCLC) using CT-corrected FDG-PET (PET/CT). Materials & Methods: Subjects were 91 NSCLC patients (M/F 62/29, age: $60{\pm}9$ yr) who underwent PET/CT before in dissection. We evaluated the maximum SUV (maxSUV), patterns of FDG uptake, short axis diameter, and calcification of LN showing abnormally increased FDG uptake. Then we investigated criteria improving the diagnostic accuracy and correlated results with postoperative pathology. In step 1, in was classified as benign or malignant based on maxSUV only. In step 2, LN was regarded as benign if it had lower maxSUV than the cut-off value of step 1 or it had calcification irrespective of its maxSUV. In step 3, LN regarded as malignant in step 2 was classified as benign if they had indiscrete margin of FDG uptake. Results: Among 432 LN groups surgically resected (28 malignant, 404 benign), 71 showed abnormally increased FDG uptake. We determined the cut-off as maxSUV=3.5 using ROC curve analysis. The sensitivity, specificity, and accuracy for assessing malignant LN were 64.3%, 86.9%, 85.4% in step 1, 64.3%, 95.0%, 93.1% in step 2, and 57.1%, 98.0%, 95.4% in step3, respectively. The accuracy for assessing N stage was 64.8% in step 1, 80.2% in step 2, and 85.7% in step 3. Conclusion: interpreting PET/CT, consideration of calcification and shape of the FDG uptake margin along with maxSUV can improve the diagnostic accuracy for assessing malignant involvement and N stage of hilar and mediastinal LNs in NSCLC.

• Journal of Gastric Cancer
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• v.9 no.4
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• pp.177-185
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• 2009

Purpose: Preoperative clinical staging of gastric cancer is very important for determining the treatment plans and predicting the prognosis. The previous reports regarding the accuracy of computed tomography or endoscopic ultrasound for the preoperative staging of gastric cancer have shown various outcomes. We analyzed the diagnostic performance of CT and EUS, which are important staging tools for the staging of TN gastric cancer. Materials and Methods: We retrospectively analyzed 1,174 patients who underwent gastrectomy for gastric cancer at Seoul National University Bundang Hostpital from May, 2003 to December, 2007. We derived the Kappa value to examine the agreement of the preoperative staging obtained from CT and EUS with the pathological staging. Results: The mean age of the 1,174 patients was $59.31{\pm}11.98$ years. Six hundred thirty seven patients had early gastric cancer and 536 had advanced gastric cancer. The diagnostic performance between CT and EUS for the T staging showed no significant difference between CT and EUS for the kappa values. The kappa values showed moderate agreement at 0.4039 (P=0.021) and 0.4201 (P=0.026), respectively. This suggests that there is no difference between the two examinations for the overall T staging. Analysis of the discrimination of mucosal and submucosal lesions with EUS showed an accuracy of 58.92% and a Kappa value of 0.206 (P<0.001), suggesting fair agreement and a lower diagnostic performance than expected. To differentiate lesions with stages higher than or equal to T2 or T3 from the lesion with stages lower than T2 or T3, respectively, adoption of the higher stage from the CT staging or the EUS staging showed a larger AUC of 0.84 than that from either stage alone. The CT-derived node stage had the higher diagnostic performance (68.55%) than that of the EUS-derived node stage (60.82%) for the node staging. Conclusion: The CT-derived stage and EUS-derived stage showed comparable results for determining the T stage of gastric cancer. Yet the higher stage of the two stages from CT and EUS most accurately discriminated between those lesions with stages higher than T2 and those lesions with stages lower than T2.

• Nuclear Medicine and Molecular Imaging
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• v.41 no.6
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• pp.553-560
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• 2007

Purpose: We evaluated the standard uptake value (SUV) of F-18 FDG at PET/CT for differentiation of benign from malignant tumor in primary musculoskeletal tumors. Materials and Methods: Forty-six tumors (11 benign and 12 malignant soft tissue tumors, 9 benign and 14 malignant bone tumors) were examined with F-18 FDG PET/CT (Discovery ST, GE) prior to tissue diagnosis. The maxSUV(maximum value of SUV) were calculated and compared between benign and malignant lesions. The lesion analysis was based on the transverse whole body image. The maxSUV with cutoff of 4.1 was used in distinguishing benign from malignant soft tissue tumor and 3.05 was used in bone tumor by ROC curve. Results: There was a statistically significant difference in maxSUV between benign (n=11; maxSUV $3.4{\pm}3.2$) and malignant (n=12; maxSUV $14.8{\pm}12.2$) lesions in soft tissue tumor (p=0.001). Between benign bone tumor (n=9; maxSUV $5.4{\pm}4.0$) and malignant bone tumor (n=14; maxSUV $7.3{\pm}3.2$), there was not a significant difference in maxSUV. The sensitivity and specificity for differentiating malignant from benign soft tissue tumor was 83% and 91%, respectively. There were four false positive malignant bone tumor cases to include fibrous dysplasia, Langerhans-cell histiocytosis (n=2) and osteoid osteoma. Also, one false positive case of malignant soft tissue tumor was nodular fasciitis. Conclusion: The maxSUV was useful for differentiation of benign from malignant lesion in primary soft tissue tumors. In bone tumor, the low maxSUV correlated well with benign lesions but high maxSUV did not always mean malignancy.

• The Korean Journal of Nuclear Medicine Technology
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• v.23 no.2
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• pp.38-42
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• 2019

Purpose Although computed tomography (CT) is used for coronary artery calcification, it is difficult to differentiate between high risk microcalcifications. Studies have shown that $^{18}F$-sodium fluoride ($^{18}F-NaF$) is very useful for the diagnosis of microcalcifications. In this study, we aimed to evaluate the usefulness of $^{18}F-NaF$ PET imaging in quantitative evaluation of calcification. Materials and Methods A total of 45 patients ($67.1{\pm}6.9years\;old$) were injected with 250 MBq of $^{18}F-NaF$ for 1 hour and images were acquired for 30 minutes. All patients underwent CT angiography (CTAngiography, CTA) before the PET scan. The SUVmax of calcification was measured and the background radioactivity of the left atrium was measured to determine Target to Background (TBR) and quantitatively analyzed. High risk group was classified through ROC curve (Receiver Operating Characteristic Curve). Results There were 226 coronary artery calcifications in the cohort and SUVmax was $1.15{\pm}0.39$. Of the 28 patients (62%), 58 were classified as high risk (TBR > 1.25). The remaining 168 were $TBR{\leq}1.25$. Conclusion $^{18}F-NaF$ PET images were available for quantitative assessment of microcalcifications and could be classified into high-risk groups. The combination of angiographic CT and $^{18}F-NaF$ PET may be a new method for early diagnosis of high-risk microcalcifications.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.142-149
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• 2009

Purpose : The aim of this study was to determine the diagnostic value of serum procalcitonin (PCT) compared with that of C-reactive protein (CRP) and the total white blood cell count (WBC) in predicting bacterial infections in febrile infants<6 months of age. Methods : A prospective study was performed with infants <6 months of age who were admitted to the Department of Pediatrics with a fever of uncertain source between July and September 2008. Spinal taps were performed according to clinical symptoms and physical examination. Serum PCT levels were measured using an enzyme-linked fluorescent assay. Results : Seventy-one infants (mean age, 2.62 months) were studied. Twenty-six infants (36.6%) had urinary tract infections (UTIs), and 22 infants (31.0%) had viral meningitis. The remaining infants had acute pharyngitis (n=1), herpangina (n=1), upper respiratory tract infections (n=7), acute bronchiolitis (n=8), acute gastroenteritis (n=4), and bacteremia (n=2). The median WBC and CRP levels were significantly higher in infants with UTIs than in infants with viral meningitis. However, there were no differences in the median PCT levels between the groups (0.14 ng/mL vs. 0.11 ng/mL, P=0.419). The area under the receiver operating characteristic curve was 0.792 (95% CI, 0.65-0.896) for WBC, 0.77 (95% CI, 0.626-0.879) for CRP, and 0.568 (95% CI, 0.417-0.710) for PCT. An elevated WBC count (>11,920/${\mu}L$) and an increased CRP level (>1.06mg/dL) were significant predictors of UTIs based on multiple logistic regression analysis. Conclusion : Serum PCT concentrations should be interpreted with caution in infants <6 months of age with a fever of uncertain source.

• Journal of radiological science and technology
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• v.31 no.3
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• pp.249-258
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• 2008

Purpose : Abdominal obesity with visceral fat accumulation have been known to be intimately associated with the development of metabolic syndrome. Therefore, it is important to estimate the precise amount of visceral fat. Ultrasonography has been reported that it is a simple and noninvasive method for visceral fat evaluation. Purpose of this study is to evaluate the association of ultrasonographic visceral fat thickness, anthropometric indexes, and risk factor of metabolic syndrome, and to investigate the cut-off value of abdominal visceral fat thickness leading to increased risk of metabolic syndrome. Materials and methods : The subject included 200 men and 200 women who visited D healthcare center in Daejeon from January to April 2008. The subcutaneous fat thickness and visceral fat thickness were measured by ultrasonograph. As anthropometric index, we measured body mass index, waist circumference and waist/height ratio. As for the risk factor of metabolic syndrome, we measured blood pressure, high density lipoprotein cholesterol, triglyceride and fasting serum glucose. Results : VFT was significantly correlated with waist circumference, (r=0.683/M, r=0.604/F), waist to height ratio (r=0.633/M, r=0.593/F) and BMI (r=0.621/M, r=0.534/F) in both men and women. In addition it was significantly correlated with Systolic blood pressure (r=0.229/M, r=0.232/F), Diastolic blood pressure ((r=0.285/M, r=0.254/F), high density cholesterol (r=-0.254/M, r=-0.254/F), Triglyceride (r=0.475/M, r=0.411/F), and Fasting blood sugar (r=0.158/M, r=0.234/F) in both men and women. The cut-off value of visceral fat thickness leading to the increased risk of metabolic syndrome was 4.58cm (sensitivity89.2%, specificity 71.2%) in men and 3.50cm (sensitivity61.2% specificity 80.8%) in women respectively. The odds ratio of the risk of metabolic syndrome was dramatically increased with the abdominal visceral fat thickness level over 6cm in men and 5cm in women. Conclusion : The visceral fat thickness using ultrasonography was significantly correlated with anthropometric indexes and risk factors of metabolic syndrome in both men and women. The cut-off value of visceral fat thickness leading to the increased risk of metabolic syndrome was 4.58cm in men and 3.50cm in women.