[Use of technical means in the implementation of the annual examination of the population].
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Due to technical improvements and new developments of immunological assays, the reliability of serological laboratory diagnosis of HIV infection has improved considerably and the residual risk, due to the diagnostic window for transfusion-transmitted HIV, has been reduced significantly. Through the addition of nucleic acid amplification tests (NAT) to blood donor screening, the residual risk can de further decreased by up to 50%, depending on the sensitivity of the NAT protocol and whether individual or pooled blood donations are screened. In-house and commercially available NAT have been implemented in blood banks as HIV only or multiplexed HIV and hepatitis B or C virus assays. As an alternative to separate antigen and antibody screening, combined fourth-generation assays have been developed in 1997, and have achieved a high degree of sensitivity and specificity. Thus, they can replace stand-alone antigen and third-generation antibody assays. While they are used in the routine diagnostics of HIV infection in many countries throughout the world, they probably represent no alternative for NAT in blood-donor screening in industrialized countries. In the next few years, technical improvements will further simplify NAT screening. While there is still some potential to improve the detection threshold of NAT, the sensitivity of the antigen module of fourth-generation assays (a lowest concentration of 3-5 pg of p24 antigen) is probably very close to its technical limit.
The increasing morbidity rate of endometrial carcinoma has prompted the development of methods of examination suitable for the detection of asymptomatic carcinoma of the endometrium. Commercially available instruments for collection of specimens from the uterine cavity employ washing, aspiration or curettage techniques. Under clinical testing conditions, these instruments have been shown to have a high cytomorphological accuracy, namely 80%. It has not yet been possible to reproduce this high level of accuracy under outpatient conditions. Hence, utilization of these techniques as screening methods in a cancer prevention programme for the early detection of endometrial cancer cannot be realized at the present time. Prerequisites for their use would be further technical improvements in instrumentation and a sufficient level of expertise in the assessment of endometrial smears by differential cytological techniques.
Renal artery stenosis (RAS) is a common condition associated with hypertension and renal insufficiency. The high prevalence of RAS patients with coronary and lower extremity vascular disease has been well established. Fibromuscular dysplasia in young females and atherosclerosis in patients over the age of 55 are the most common causes. Poorly controlled hypertension refractory to medical therapy, worsening of renal function, and flash pulmonary edema may point to underlying RAS. Duplex ultrasonography and magnetic resonance angiography have largely replaced captopril scanning for RAS screening. However, renal angiography still remains the gold standard to diagnose RAS. Treatment options include medical therapy, angioplasty, and surgery. In general, patients with a stenosis greater than 50%, a translesional systolic pressure gradient greater than 15 mm Hg, and difficult-to-control hypertension and/or worsening renal insufficiency are candidates for renal revascularization. Percutaneous transluminal revascularization has evolved to become the preferred revascularization therapy because it is a less invasive and more cost-effective alternative to surgery and is associated with high technical success, as well as a low complication rate. The natural history of RAS is to progress over time, leading to renal artery occlusion, loss of renal mass, worsening of renal function, and, ultimately, end-stage renal disease. It is therefore important to aggressively screen, recognize, and treat the entity early in its course.
The first 18 months' experience of the Breast Diagnostic Center of Jefferson Medical College have been reviewed. Almost 14,000 patients were screened for breast disease, using a combination of clinical examination. Xeroradiography, and thermography. In this group of 14,000 women, 106 cases of cancer were discovered, in incidence of almost 8 per 1000 women screened. Of these 106 cases of cancer, 45.3% were clinically occult or not recognized by clinical examination, and within this group at the time of mastectomy only a small percent had any evidence of axillary lymph node metastases. The combination of several technics of examination is proving to be more reliable for the early detection of breast cancer than any of the technics alone, and programs such as these may make a significant difference in the death rate from breast cancer.
AIMS: To evaluate the introduction of a community-based non-mydriatic and mydriatic digital photographic screening programme by measuring the sensitivity and specificity compared with a reference standard and assessing the added value of technician direct ophthalmoscopy. METHODS: Study patients had one-field, non-mydriatic, 45 degrees digital imaging photography prior to mydriatic two-field digital imaging photography followed by technician ophthalmoscopy. Of these patients, 1549 were then examined by an experienced ophthalmologist using slit lamp biomicroscopy as a reference standard. The setting was general practices in Gloucestershire. Patients were selected by randomizing groups of patients (from within individual general practices) and 3611 patients were included in the study. Patients for reference standard examination were recruited from groups of patients on days when the ophthalmologist was able to attend. The main outcome measure was detection of referable diabetic retinopathy (DR) as defined by the Gloucestershire adaptation of the European Working Party guidelines. RESULTS: For mydriatic digital photography, the sensitivity was 87.8%, specificity was 86.1% and technical failure rate was 3.7%. Technician ophthalmoscopy did not alter these figures. For non-mydriatic photography, the sensitivity was 86.0%, specificity was 76.7% and technical failure rate was 19.7%. CONCLUSIONS: Two-field mydriatic digital photography is an effective method of screening for referable diabetic retinopathy. Non-mydriatic digital photography has an unacceptable technical failure rate and low specificity.
The use of computed tomography (CT) for screening of targeted diseases is gaining much interest in the international medical community. An important aspect in the justification of screening with such a high dose examination is the radiation dose to the patient. The objective of this study was to perform a prospective assessment of the radiation dose and associated risk for deleterious effects from a CT screening programme. The excess lifetime risk of fatal cancer for various screening strategies was quantified by estimating the effective dose and by using age dependent mortality risk factors. The accrued data shows that the excess mortality risk due to screening with CT could be substantial. It ranges from 0.01% up to a few percent, strongly depending on the type and method of screening. Consequently, radiation dose and associate risk should be included as fundamental parameters for outlining and deciding a screening approach with CT. Recent technical developments, such as tube current modulation, are promising tools for dose reduction within the constraint of desired image quality.
The dose required in x-ray diagnosis depends upon the demands made on a diagnostically optimal x-ray film or in fluoroscopy, and upon the technical quality of the equipment. The actual dose requirement, derived from field studies, is juxtaposed on the basis of representative examples with the maximum permissible dose requirement in accordance with the prescribed minimum sensitivity values of the x-ray film. The ideal dose requirement has been stated by Cohen et al. (1981) by a formula basing on parallel beam, maximum quantum yield and Bucky grid effect depending on the signal to noise ratio and object contrast. This was checked by means of contrast detail diagrams measured at the hole phantom, and was additionally compared with measurement results obtained by Wust et al. (1989) with acrylic glass phantoms. The optimal dose requirement is obtained by the maximum technically possible approach to the ideal requirement level. Examples are given, besides for x-ray equipment with Gd2 O2 S screen film systems for grid screen mammography, and new thoracic examination systems for mass screenings. Finally, a few values concerning the dose requirement or the analogous time required for fluorescent screening in angiography and interventional radiology, are stated, as well as for dentistry and paediatric x-ray diagnostics.
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Screening for disease control can be defined as a preventive technology that is used to examine asymptomatic people in order to classify them as likely or unlikely to have the disease that is the object of screening. Screening may consist of routine physical examinations, radiologic procedures, semi-invasive procedures such as endoscopy, or serologic tests. In this paper, a new serologic test is considered. Acquired immunodeficiency syndrome (AIDS) is a devastating disease with high mortality, recently shown to be caused by a retrovirus named human T-lymphotropic virus Type III (HTLV-III) or lymphadenopathy-associated virus HTLV-III antibody in serum specimens. Performance characteristics are excellent with high sensitivity and specificity when reactive serum specimens are checked for consistency of response by enzyme immunoassay (EIA). This test is now part of the screening protocol for all blood donation centers to decrease the risk of HTLV-III transmission via blood or blood products. About 0.2% (1 in 400) of blood donors have repeatedly reactive EIA tests to HTLV-III antibody. Approximately one-third of these donors have other laboratory evidence of infection. Screening for HTLV-III is a new technology that illustrates virtually all of the factors that need consideration in an assessment of disease screening. This paper explores these technical, epidemiologic, economic, legal, social, and ethical factors.
A Leprosy Elimination Campaign (LEC) is an initiative which aims to detect leprosy cases, particularly the more serious ones referred to as 'cases of consequence', that remain undetected in the community, and to treat them with MDT. This will subsequently reduce the delay in managing such cases in the community and ensure that the existing health services are able to treat them. It is a time-bound, one-time activity. Leprosy of consequence is defined as cases with more than five skin lesions and skin smear positive cases. Such cases are regarded as being of consequence because they act as a major source of infection in the community and are either already disabled or at high risk of becoming disabled. LEC is a focused combination of activities which includes: orientation courses for local health workers and volunteers; community awareness creation activities; case-finding and treating every detected case immediately with MDT. These campaigns are to be carried out primarily in endemic regions where the prevalence and new case detections are high and where the gap between estimated and registered cases is large. It is a national activity, implemented by the national staff with technical cooperation from WHO and other agencies.
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Although there is good evidence that carcinomas of the prostate are usually seen as echopenic masses within the external zone of the prostate, it is unclear how often an echopenic mass has an origin other than carcinoma of the prostate. Technical problems at the periphery of the gland not uncommonly create echopenic areas on an artifactual basis. Whether ultrasound will prove to be a satisfactory screening method for the detection of carcinoma of the prostate is yet to be decided. Prospective studies are in progress, but it has not yet been established whether prostate screening is a worthwhile procedure. The best possible equipment is required to detect these subtle lesions; cheap equipment will probably not give adequate results.
Despite the limitations of US in providing a complete evaluation of renal tumors before treatment planning, initial screening, characterization of renal masses and staging of RCCs can benefit from some recent advances of the technique. One of the most relevant clinical benefits of US is the increased early detection of RCCs. Recent technical improvement of gray-scale imaging has increased US performance in the detection of small renal tumors. Combined gray-scale and color Doppler US findings may strongly suggest the histopathologic nature of a renal tumor with respect to the size, the US attenuation characteristics, and the vascular distribution of the lesion. Ultrasound contributes additional diagnostic information for differential diagnosis of some renal masses that remain equivocal at CT, including: atypical cystic lesions; solid renal tumors with poor vascularity; and angiomyolipomas with minimal fat component. Ultrasound also may provide additional diagnostic information over CT in selected cases of RCCs with venous invasion. In addition to some diagnostic and therapeutic procedures that can benefit from US guidance, intraoperative US remains the only available tool that enables to ensure renal-parenchymal-sparing surgery.
in 220 women with gynecologic symptoms, endometrial washings were obtained with the Gravlee Jet Washer-in 135 outpatients before office curettage without anesthesia or analgesia; in 85 hospitalized patients before fractional dilatation and curettage under anesthesia. The method was simple, inexpensive, virtually painless, and free of complications. Endometrial adenocarcinoma was present in 12 patients; the jet washing samples were diagnostic in 6 of these. Reported variations in diagnostic accuracy for endometrial carcinoma and precancerous phases raise doubts as to the value of this technic in asymptomatic patients. It is valid for screening symptomatic patients provided results other than normal or positive are further evaluated. Laboratory handling and interpretation must be improved if jet washing is to succeed in mass screening programs.