• Title/Summary/Keyword: False-negative results

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Application of Polymerase Chain Reaction (PCR) to the Diagnosis of Tuberculosis (Polymerase Chain Reaction (PCR)을 이용한 결핵의 진단에 관한 연구)

  • Kim, Ho-Joong;Kim, Young-Whan;Han, Sung-Koo;Shim, Young-Soo;Kim, Keun-Youl;Han, Yong-Chol
    • Tuberculosis and Respiratory Diseases
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    • v.39 no.6
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    • pp.517-525
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    • 1992
  • Background: Since its development by Saiki et al, polymerase chain reaction (PCR) has been very useful in various fields of molecular biology. PCR can be used for the detection of a very small amount of microbial agent, and is especially useful in those patients who are difficult to diagnose microbiologically or serologically. Mycobacterium tuberculosis is a very slowly growing organism and AFB staining frequently shows false negative results, and therefore PCR would be a very rapid, easy, and sensitive diagnostic method for the diagnosis of Mycobacterium tuberculosis. Method: To compare PCR with conventional methods in diagnosing Mycobacterium tuberculosis in sputum, we used sputa of patients who visited or were admitted to Seoul National University Hospital. The amplification targets were 383 base pair DNA, a part of 2520 base pair DNA encoding 65 kD Mycobacterium tuberculosis specific protein (the primers are TB-1, -2), and 123 base pair DNA, a part of IS6110 fragment, which multiple copies are known to exsist PCR one genome (the primers are Sal I-1, -2). We also requested AFB staing and culture to the lab of Seoul National University Hospital with the same sample and compared the results. Results: 1) Using TB-1, -2 primers, PCR was positive in 73.1% (19/26) of culture positive sputa, in 12.5% (1/8) of culture negative. but clinically diagnosed tuberculous sputa, and was negative in all sputa of patients who were clinically diagnosed as non-tuberculous etiology. 2) Using Sal I-I, -2 primers, PCR was positive in 94.1% (32/34) of culture positive sputa, in 23.1% (6/26) of culture negative, but clinically diagnosed tuberculous sputa, and was negative in 87.5% (14/16) of sputa from patients who were clinically diagnosed as non-tuberculous etiology. Conclusion: PCR could be a very rapid, sensitive and specific method for the diagnosis of Mycobacterium tuberculosis in sputa, and further studies should be followed for the development of easier method.

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Performance Evaluation of Substitution Radiopharmaceutical according to Restriction of the Radiocolloids in Lymphoscintigraphy (Lymphoscintigraphy에 이용되는 방사성의약품의 사용제한으로 인한 대체 방사성의약품의 성능평가)

  • Seo, Young-Deok;Jeong, Jae-Hun;Moon, Jong-Woon;Yun, Sang-Hyeok;Kim, Yeong-Seok;Kang, Se-Hun;Won, Woo-Jae;Kim, Seok-Ki
    • The Korean Journal of Nuclear Medicine Technology
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    • v.13 no.1
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    • pp.25-29
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    • 2009
  • Purpose: Several radioactive agents were used for lymphoscintigraphy in breast cancer. But recently, due to the change of local radiopharmaceutical licensing policy and discontinuation of supplies from manufacturer, we could not use many radiocolloids such as $^{99m}Tc$-Antimony Trisulfide Colloid, $^{99m}Tc$-Tin Colloid, $^{99m}Tc$-Human Serum Albumin. So it is necessary to use the substitution radiopharmaceutical. Therefore, this study aims to evaluate the performance of substitution radiopharmaceutical ($^{99m}Tc$-Phytate) including the existing radiocolloids and to set up of the appropriate protocol in lymphoscintigraphy. Materials and Methods: For each radiocolloids ($^{99m}Tc$-Antimony Trisulfide Colloid (ASC), $^{99m}Tc$-Tin Colloid (TC), $^{99m}Tc$-Human Serum Albumin (HSA), $^{99m}Tc$-Phytate) were performed the particle size by Zeta Sizer (Nano-ZS) and we compared the radiolabeling time, procedure and acquisition time for each of the radiocolloids (total 200 patients). For the last time, we made an analysis of image for each of the radiocolloids with our previous report (SJ Jang et al, Korean Nucl Med Mol imaging Vol.41, No.6, Dec 2007). Results: The particle size of each radiocolloids showed A.S.C (50 nm), T.C (310 nm), H.S.A (10.8 nm), $^{99m}Tc$-Phytate (499 nm). The labeling and acquisition time for each of the radiocolloids showed no substantial difference. But there is difference of the labeling time for the A.S.C. because the ASC procedure need to boiling process. There were no significant differences among those radiocolloids (p>0.005) in the identification rate (IR), false negative rate (FNR), and negative predictive value (NPV). Conclusions: $^{99m}Tc$-labeled radiocolloids showed equivalent results in lymphoscintigraphy. Therefore, in this exam of each radiocolloids could be applied appropriate protocol in lymphoscintigraphy.

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A CLINICO-STATISTICAL STUDY ON CERVICAL LYMPH NODE METASTASIS OF ORAL SQUAMOUS CELL CARCINOMA (구강 편평세포암종의 경부 림프절전이에 대한 임상통계학적 연구)

  • Lee, Jae-Wook;Kim, Jin-Wook;Kim, Chin-Soo
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.34 no.6
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    • pp.594-601
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    • 2008
  • Cervical lymph node metastasis is one of the most important predicting factors that influence the prognosis of oral squamous cell carcinoma. Correct diagnosis on cervical lymph node metastasis is essential in determining the extent of operation and treatment modality. So we investigated a clinico-statistical evaluation on cervical lymph node metastasis in 183 patients who were diagnosed with oral squamous cell carcinoma at the Department of Oral and Maxillofacial Surgery in Kyungpook National University Hospital, from January 1st, 1999 to December 31st, 2007. The following results were obtained : 1. Among 183 patients who were diagnosed with oral squamous cell carcinoma, 149 were male and 49 were female. The average age of the patients was 61.8 years old. 2. Patients with advanced T classification showed higher incidence of cervical lymph node metastasis than those with lower T classification. 3. Patients with less differentiated tumors had higher tendency of manifesting cervical lymph node metastasis than those with more differentiated tumors. 4. Sensitivity and specificity on PET/CT was 87.5% and 58.3% respectively. PET/CT showed higher sensitivity and lower false-negative values than those of CT or USG. 5. The 5 - year survival rate of all the oral squamous cell carcinoma patients appeared to be 63.2% By N classification, patients in N0 stage showed a higher survival rate than patients in N1 or N2. 5 - year survival rates according to the modality of neck dissection were as follows in increasing order: no neck dissection group, MRND group, SND group, and RND group.

Detection Rate of Intravascular Injections during Cervical Medial Branch Blocks: A Comparison of Digital Subtraction Angiography and Static Images from Conventional Fluoroscopy

  • Jeon, Young Hoon;Kim, Sae Young
    • The Korean Journal of Pain
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    • v.28 no.2
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    • pp.105-108
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    • 2015
  • Background: The most definitive diagnosis of neck pain caused by facet joints can be obtained through cervical medial branch blocks (CMBBs). However, intravascular injections need to be carefully monitored, as they can increase the risk of false-negative blocks when diagnosing cervical facet joint syndrome. In addition, intravascular injections can cause neurologic deficits such as spinal infarction or cerebral infarction. Digital subtraction angiography (DSA) is a radiological technique that can be used to clearly visualize the blood vessels from surrounding bones or dense soft tissues. The purpose of this study was to compare the rate of detection of intravascular injections during CMBBs using DSA and static images obtained through conventional fluoroscopy. Methods: Seventy-two patients were included, and a total of 178 CMBBs were performed. The respective incidences of intravascular injections during CMBBs using DSA and static images from conventional fluoroscopy were measured. Results: A total of 178 CMBBs were performed on 72 patients. All cases of intravascular injections evidenced by the static images were detected by the DSAs. The detection rate of intravascular injections was higher from DSA images than from static images (10.7% vs. 1.7%, P < 0.001). Conclusions: According to these findings, the use of DSA can improve the detection rate of intravascular injections during CMBBs. The use of DSA may therefore lead to an increase in the diagnostic and therapeutic value of CMBBs. In addition, it can decrease the incidence of potential side effects during CMBBs.

Evaluation of ROC Curve in High Kilovoltage Technique Using Simulated Nodules on Chest (고관전압 흉부촬영의 가상결절을 이용한 ROC평가)

  • Ahn, Jin-Shin;Chang, Myung-Mi;Chung, Kyung-Mo;Cheung, Hwan;Lim, Jung-Ki;Kim, Jong-Hyo
    • Journal of radiological science and technology
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    • v.15 no.2
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    • pp.25-30
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    • 1992
  • With transmitted dose through chest which has the problem of wide variations in absorption, simple film/screen combination method makes it diffucult to image lung field, mediastinum and retrocardiac areas. In order to overcome this, it is very common to use the high kilovoltage technique in diminishing the differences between high and low contrast. We have been adopting this method at department of diagnostic radiology, Seoul National University Hospital. To compare the image of it with that of low kilovoltage technique, we did radiographic tests using beans on the skin. We marked off into three anatomical categories such as lungs, mediastinum and near diaphragm, then attached a bean on a marked area at random. In order to compare with high and low, we took a radiography of high($120{\sim}140\;kVp$) and low($70{\sim}90\;kVp$) kilovoltage tehchniques, respectively at the same time. We have done experiments 320 cases. We evaluated the results of test in response to sensitivity(true positive) and specificity(true negative). In evaluating, we gave them points from 1 to 5 according to true or false. With given points by a radiologist having much experiences, we could acquire the percentage of sensitivity and specificity. The percentage made us to get the schematic table of ROC curve of those two methods. Consequently, high kilovoltage technique appeared 18% better than low kilovoltage technique for detecting beans with our apparatus.

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A Unknown Phishing Site Detection Method in the Interior Network Environment (내부 네트워크에서 알려지지 않은 피싱사이트 탐지방안)

  • Park, Jeonguk;Cho, Gihwan
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.25 no.2
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    • pp.313-320
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    • 2015
  • While various phishing attacks are getting to be increased in constant, their response methods still stay on the stage of responding after identifying an attack. To detect a phishing site ahead of an attack, a method has been suggested with utilizing the Referer header field of HTTP. However, it has a limitation to implement a traffic gathering system for each of prospective target hosts. This paper presents a unknown phishing site detection method in the Interior network environment. Whenever a user try to connect a phishing site, its traffic is pre-processed with considering of the characteristics of HTTP protocol and phishing site. The phishing site detection phase detects a suspicious site under phishing with analysing HTTP content. To validate the proposed method, some evaluations were conducted with 100 phishing URLs along with 100 normal URLs. The experimental results show that our method achieves higher phishing site detection rate than that of existing detection methods, as 66% detection rate for the phishing URLs, and 0% false negative rate for the normal URLs.

A Study of Immune Response to Hepatitis B Vaccine & HBV DNA in Isolated Anti-HBc Positive Subjects (Anti-HBc 단독 양성자에서 B형 간염 백신 접종의 면역 반응과 B형 간염 DNA의 조사)

  • Kim, Soon-Duck;Choi, Ji-Ho;Kim, Sung-Ryul;Lee, Jin-Soo;Koh, Hee-Jeong
    • Journal of Preventive Medicine and Public Health
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    • v.38 no.2
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    • pp.170-174
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    • 2005
  • Objectives: The aim of this study was to evaluate the response to a hepatitis B vaccination, and investigate the HBV DNA in subjects with isolated anti-HBc. Methods: 34 subjects with persistent isolated anti-HBc were included in the study. 32 subjects negative for HBsAg, anti-HBs and anti-HBc were included as a control group. They were all vaccinated with Hepaccine at 0, 1 and 2 months, and anti-HBs titers were measured 1 month after the 1st and 3rd vaccinations (1 and 3 months). The HBV-DNA was tested by polymerase chain reaction in subjects with isolated anti-HBc. Results: After the 1st & 3rd vaccinations, the anti-HBs titers$\geq$10mIU/ml were 70.6 & 70.6% in isolated anti-HBc group, and 34.4 & 81.2% in the control group, respectively. There were statistically significant differences after the 1st vaccination, but none after the 3rd, between the two groups. In the isolated anti-HBc and control groups, the primary, amnestic and no responses were 0 vs. 46.9%, 55.9 vs. 6.3% and 29.4 vs. 18.8%, respectively. The HBV DNA was not detected in all subjects with isolated anti-HBc. Conclusion: None of the subjects with isolated anti-HBc had a false positive result (primary response); therefore, they should be excluded from vaccination programs in Korea. To differentiate between immunity and occult infections, a single dose of vaccine, with a follow-up anti-HBs test, is preferable for subjects with isolated anti-HBc. An amnestic response indicates late immunity, and no response a suspect occult infection.

Knowledge, Behavior and Beliefs Related to Cervical Cancer and Screening Among Turkish Women

  • Reis, Nesrin;Bebis, Hatice;Kose, Sevinc;Sis, Asli;Engin, Raziye;Yavan, Tulay
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.4
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    • pp.1463-1470
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    • 2012
  • Objective: The aims of this study were to explore Turkish women's knowledge, behavior and beliefs related to cervical cancer and screening. Methods: The study was performed in two cities in the East of Turkey between September 2009 and April 2010, with a sampling group of 387 women. Data were collected by means of an interview form with the Health Belief Model Scale for Cervical Cancer and Pap Smear Test - Turkish Version. Results: Women in the research group were found to have poor knowledge, inadequate health behavior and low/medium level false beliefs regarding cervical cancer screening. There was relation between health beliefs and characteristics of women and particularly education (F = 10.80, p = 0.01). Similarly, it was found that Pap smear barriers were influenced by demographic characteristics and that women with low-level education (p = 0.001), divorced women (p = 0.05), women with low-income(p = 0.05), women who gave their first birth when they were 18 or younger (p = 0.05) and women not applying any contraceptive method at all (p = 0.01) were determined to have negative Pap smear barriers. Conclusions: Primarily the knowledge, attitudes and beliefs of women in the target group should be evaluated to increase their participation in cervical cancer screening and to prepare effective education strategies.

Face Detection Method Based on Color Constancy and Geometrical Analysis (색 항등성과 기하학적 분석 기반 얼굴 검출 기법)

  • Lee, Woo-Ram;Hwang, Dong-Guk;Jun, Byoung-Min
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.48 no.4
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    • pp.59-66
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    • 2011
  • In this paper, we propose a face detection method based on color constancy and geometrical analysis. With the problem about the various colors of skin under scene illuminant, a color constancy method is applied to input images and geometrical analysis is used to detect face regions. At first, the candidates of face or hair are extracted from the image that a color constancy method is applied to, and are classified by some geometrical criterions. And then, face candidates which have some intersectional regions whose total is over a certain size, with hair candidates are selected as faces. Caltech Face DB was used to compare the performance of our method. Also, performance about scene illuminant was evaluated by images which have some illumination effects. The experiment results show that the proposed face detection method was applicable to various facial images because of high true-positive and low false-negative ration.

A Clinical Study on Surgical Thyroid Nodules (외과적 갑상선 결절에 대한 임상적 고찰)

  • Park Hyeon-Jung;Moon Sang-Eun
    • Korean Journal of Head & Neck Oncology
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    • v.9 no.2
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    • pp.234-243
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    • 1993
  • The thyroid nodules are the most common endocrine disease requiring surgical management. Up to date, various diagnostic techniques and surgical management have been developed. Authors analysed 2285 cases of thyroid nodules who were treated at Department of Surgery, Pusan National University for the duration of 10 years from January 1980 to December 1989 and the results obtained were summerized as follows: 1) Patients were composed of 1727 cases(75.8%) of benign nodule and 558 cases(24.5%) of malignant nodule. Benign nodule was prevalent in forth and fifth decade comparing with malignant nodule was sixth and fifth decade. The sexual distribution revealed female preponderance with 1:10.8 in benign nodule and 1:9.3 in malignant nodule. 2) The histopathologic classfication of benign nodule in decreasing order of frequency were follicular adenoma 1009 cases(54.8%), adenomatous goiter 573 cases(33.3%), simple cyst 65 cases(3.8%), and Hashimoto's thyroiditis 52 cases(3.0%). The malignant disease were papillary adenocarcinoma 460 cases(82.4%), follicular adenocarcinoma 69 cases(12.4%), undifferentiated carcinoma 13 cases (2.0%), and medullary carcinoma 7 cases(1.0%). 3) Fine needle aspiration cytology was performed in 1758 cases and it showed 80.5% of sensitivity, 96.5% of specificity, 19.5% of false negative and 80% of accuracy. 4) The location of nodule was 87.7%, in unilateral, 12.2% in bilateral. 5) On the radioiodine scanning, the incidence of benign nodule with cold nodule was 83.9% and the incidence of benign nodule with hot nodule was 7.5%. The incidence of thyroid carcinoma with cold nodule was 88.3% and the incidence of thyroid carcinoma with hot nodule was 4.6%. 6) Most cases of benign nodules were treated with lobectomy 82.6%, subtotal thyroidectomy 10.1% and subtotal lobectomy 3.0%. Malignant nodules were treated with lobectomy and/or isthmusectomy 37.6%, total thyroidectomy 17.7%, subtotal thyroidectomy 15.4%, and any thyroidectomy and neck dissection 13.5%. 7) Postoperative complications were developed in 3.8% of benign nodules and 13.8% of malignant nodules.

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