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PubMed1985

Limited information, medical entitlements and distributive justice.

This paper asks the question of how much should society spend on diagnosis as opposed to medical treatments and compensation when implementing its goals of distributive justice in health policy through publicly-funded medical entitlement programs in a world of limited information? A model is presented in which social planners seek to maximize expected social welfare by allocating medical goods, including diagnostic tests among medically dissimilar individuals when there is imperfect information about the medical condition of an individual, subject to the resource constraints of a medical entitlement fund. The goals of distributive justice underlying the social welfare function is governed by a parameter representing society's aversion to inequality. It is argued that society, given its aversion to inequality, need not always entitle the medically more fortunate individual to less treatment and compensation. Moreover, in most cases, it is socially desirable to spend a finite and equal amount on diagnostic tests for each individual, even though there is some probability of misdiagnosis. In some unusual cases, zero expenditures on diagnostic tests will be socially optimal.

Canada↗
PubMedDate not supplied

Noninvasive diagnostic testing of coronary artery disease in women.

Noninvasive diagnostic testing of coronary artery disease (CAD) is widely recognized as an area that is less studied and less accurate with regard to women than to men. Accurate and safe diagnostic testing constitutes the crucial link between early detection and optimal management of CAD. Many noninvasive diagnostic modalities are available to the clinician, including traditional electrocardiography, the relatively novel imaging of echocardiography, the emerging nuclear perfusion technology of electron beam computed tomography, exercise testing, and pharmacologic testing. The most accurate and cost-effective diagnostic method for patients depends on the patients' pretest likelihood of the disease as determined by factors such as sex, age, and cardiovascular risk factors. Noninvasive tests are most useful in the diagnosis of CAD in patients with intermediate pretest likelihood of CAD. Patients with low pretest likelihood of CAD with normal electrocardiograms may benefit from noninvasive tests or a watchful waiting strategy. Patients with a high pretest likelihood of CAD may benefit greatly from direct referral to coronary angiography. Among the noninvasive diagnostic methods, exercise electrocardiography is the most studied and least accurate with regard to women patients. Electrocardiography improves in accuracy when combined with imaging techniques such as echocardiography or nuclear single photon emission computed tomography. Combining data from all studies has shown that exercise echocardiography yields the highest diagnostic accuracy in women among all of the exercise stress tests. Patients who are unable to achieve maximal exercise capacity may undergo pharmacologic testing using dipyridamole or adenosine radionuclide perfusion or dobutamine echocardiography. Recent development of electron beam computed tomography accurately detects coronary artery calcium but has not been validated yet as a standard diagnostic test for CAD.

Coronary Angiography↗
PubMed1991

Principal advantages of CNS diagnostics by magnetic resonance imaging.

In this paper the authors present the principal advantages and values of CNS diagnostics by magnetic resonance imaging (MRI), on the basis of the data from the available literature as well as on the 3-year experience of the MRI Institute in Innsbruck. Also, qualitative advantages of MR 1.5 T over other, less powerful machines, have been emphasized. So far, the experience has proved that, for the moment, the 1.5 MR machine offers optimal characteristics for the diagnostics of the CNS diseases.

Adult↗
PubMed1997

Eradication of wild poliovirus from the Americas: wild poliovirus surveillance--laboratory issues.

The Pan American Regional Poliomyelitis Laboratory Network, developed to support the program to eradicate indigenous wild poliovirus transmission in the Americas, included 10 laboratories, distributed in eight countries in the Americas, organized according to the diagnostic procedures they regularly performed. All laboratories isolated and typed virus in stool specimens, several did intratypic differentiation by nucleic acid probe hybridization, and 2 sequenced wild poliovirus isolates for molecular epidemiologic studies. High performance of the network was maintained through comprehensive training of virologists, continuous monitoring of laboratory performance, and prompt investigation of problems. Recommended field and laboratory procedures were regularly reviewed and revised to optimize sensitivity, specificity, and diagnostic efficiency. Close integration of field and laboratory surveillance was achieved through frequent meetings between virologists and epidemiologists, effective communication of program priorities, and the distribution of weekly surveillance reports.

Americas↗
PubMed1991

[Methods of selection of cutoff points in the development and interpretation of diagnostic tests].

Problems related to the optimization of diagnosis making are scrutinized. Applied immunological tests for diagnosis of ovarian cancers are used as an example of ROC curve calculation. Moreover, sensitivity and specificity grades are computed in order to obtain the optimum of diagnostical robustness. The ROC analysis is supplemented with application of Bayes diagnostical algorithm. The analysis is given also of other problems concerning with implementation of quantitative characteristics in the course of diagnostical decision making.

Bayes Theorem↗
PubMed2006

Severe anemia owing to occult pulmonary hemorrhage: a diagnostic pitfall.

The purpose of this paper is to increase the awareness about pulmonary hemorrhage as a possible cause of microcytic hypochromic anemia and to delineate diagnostic difficulties and possible pitfalls. An instructive case of anemia of unclear origin referred to our institution for a hematologic workup is presented. Microcytic hypochromic anemia owing to repeated occult alveolar hemorrhages was the only clinical sign of idiopathic pulmonary hemosiderosis in this case. The laboratory finding constellation in such cases may be misleading and may lead to misinterpretation. Awareness about this condition among pediatricians and hematologists can optimize and accelerate the diagnostic process.

Anemia, Hypochromic↗
PubMed2004

Usefulness of narrow-band imaging endoscopy for diagnosis of Barrett's esophagus.

BACKGROUND: A newly developed endoscope lighting system called a narrow-band imaging system emphasizes certain histological features such as capillary and crypt pattern. The usefulness of NBI for the diagnosis of Barrett's esophagus (BE) was evaluated. METHODS: Eleven patients with previously diagnosed BE were enrolled in this study. Magnifying endoscopy was performed by an experienced endoscopist, using both a conventional system and an NBI system. All images were recorded by video and by a digital still image filing system. Differences in images were evaluated by another experienced endoscopist. The quality of images for the visualization of the esophagogastric junction, capillary vessels, and columnar-lined esophagus (CLE) was judged as: optimal (score of 4), diagnostic (3), suboptimal (2), or nondiagnostic (1). RESULTS: In contrast to the low rate of visualization of the esophagogastric junction by conventional endoscopy, visualization of this area endoscopy was better by NBI. Net-like blood vessels were more clearly seen on images obtained by NBI endoscopy. Visualization of the CLE was better by NBI endoscopy than by conventional endoscopy. In contrast to conventional endoscopy, NBI endoscopy captured the optimal view of Barrett's epithelium. The relationship between the endoscopic and histopathologic diagnoses was more accurate by NBI endoscopy than by conventional endoscopy. CONCLUSIONS: Magnifying endoscopy by NBI is more useful than conventional magnifying endoscopy for the diagnosis of BE.

Barrett Esophagus↗
PubMed1991

[Risk assessment in diagnostic radiation dosimetry].

Regulation of radiological protection in diagnostic radiology is based primarily on theoretical assumptions and hypotheses rather than on quantitative data regarding harmful effects. Bionegative effects of low doses have not been demonstrated in individuals or by epidemiological data. Nonetheless, in every case involving radiodiagnostic or nuclear medicine procedures, a benefit-versus-risk analysis is necessary. Therefore, knowledge of both radiobiological aspects and all the above assumptions, hypotheses and simplifications are necessary in order to optimize radiological protection in diagnostic radiology.

Dose-Response Relationship, Radiation↗
PubMed2002

An ex vivo study exploring the diagnostic potential of 1H magnetic resonance spectroscopy in squamous cell carcinoma of the head and neck region.

BACKGROUND: Definitive diagnosis of head and neck cancer is generally made by histopathologic evaluation. Management and prognosis largely depend on accurate and timely diagnosis. We have explored the use of (1)H magnetic resonance spectroscopy in search of a better or complementary diagnostic technique. METHODS: Tumor and adjacent normal tissue specimens (n = 135) from untreated head and neck cancer patients (n = 40) were obtained and subjected to spectroscopic evaluation followed by histopathologic analysis. Data were partitioned into training and test sets and subjected to multivariate analysis. RESULTS: The resonances from taurine, choline, glutamic acid, lactic acid, and lipid were found to have diagnostic potential by our optimal region selection algorithm. Multivariate analysis of the spectral data differentiated between normal and malignant tissues, with an overall accuracy of 92.6% (training set, 97.3%; test set, 87.3%), an overall sensitivity of 93% (test set, 90%), and an overall specificity of 92% (test set, 82.6%). CONCLUSIONS: (1)H magnetic resonance spectroscopy combined with multivariate methods of analysis can distinguish between normal and malignant squamous cell tissue, and this may lead to the development of an objective and noninvasive diagnostic procedure.

Adult↗
PubMedDate not supplied

Tumor markers as targets for selective diagnostic and therapeutic procedures.

Monoclonal antibodies (MAbs) that are reactive with tumor associated antigens (TAAs) have led to many of the recent advances made in tumor immunology. At the present time, many of these MAbs have already been used in various aspects of patient management and in better understanding the biology of carcinoma cell populations. Because of their diversity, specificity and biological activity, these MAbs are potentially ideal agents for a variety of applications in malignant disorders such as, clinical diagnosis using serum assays, immunocytopathological analyses of effusions or fine-needle aspiration specimens, immunoscintigraphy, radioimmunoguided surgery and, with additional development, site directed immunotherapy. Nevertheless, their clinical application shows advantages and limitations. Optimization of their clinical use is actually under evaluation in several Institutions, including our Department. Many innovations have been developed over the last decade which may enhance their clinical efficacy. In this view, an optimal tumor targeting for diagnostic or therapeutic applications may require a better choice of radiotracer, generation of new molecules and the characterization of TAAs at the target level.

Antibodies, Monoclonal↗
PubMed1992

Automatic film processing: analysis of 9 years of observations.

A survey method known as the sensitometric technique for the evaluation of processing (STEP) has been used to monitor processing speed of over 2,000 automatic film processors in hospitals, private offices, and mammography facilities since 1981. Analysis of data obtained through this program revealed underprocessing at 33% (76 of 231) of observed hospitals in 1987, 7% (13 of 179) of mammography facilities in 1988, and 42% (101 of 241) of private practices in 1989. Underprocessing at mammography facilities decreased from 18% (25 of 139) in 1985, which was contrary to the trend in hospitals. The consequence of underprocessing is higher radiation exposure and a degradation in film contrast. Evaluation of automatic film processors is a necessary part of any comprehensive evaluation of a diagnostic radiography facility. The STEP procedure was designed only as a field survey test; to ensure optimal conditions for obtainment of diagnostic quality radiographs, facilities should perform quality assurance evaluations of their processing equipment and verify that processing recommendations of manufacturers are being followed.

Technology, Radiologic↗
PubMedDate not supplied

An exponential model used for optimal threshold selection on ROC curves.

A two-parameter exponential equation for modeling a receiver operating characteristic (ROC) curve is presented, where the area under the curve is a simple function of one of the parameters. The model makes no distributional assumptions about the underlying normal and abnormal patient populations or about the shape of the resulting ROC curves. In a computer simulation of 75 ROC curves, the model provides a fit equivalent to the maximum likelihood estimate method commonly used for ROC curve fitting. Similar results are obtained using the model to fit ROC curve data from the literature. The model's equation calculates the true-positive ratio as a function of the false-positive ratio, and has a first derivative that is useful for finding the optimal decision threshold for a diagnostic testing procedure. In particular, the model is useful in a computer program for finding jointly optimal thresholds for multiple sequential tests.

Computer Simulation↗
PubMed1999

Canadian Helicobacter Study Group Consensus Conference on the Approach to Helicobacter pylori Infection in Children and Adolescents.

Gastric infection with Helicobacter pylori is common in both children and adults, but children are considerably less susceptible to peptic ulcers and other pathological sequelae. As a result, the risk to benefit ratio of diagnostic studies and therapeutic regimens for H pylori in adults are likely different from those in pediatric populations. These guidelines for the management of pediatric H pylori infection, developed by the Canadian Helicobacter Study Group, are designed to identify when the diagnosis and treatment of H pylori may improve patient care. Given the low prevalence of this infection in Canada, it is important to recognize that indiscriminate testing and treatment programs in children are not recommended, and indeed may threaten the optimal care of children. Diagnostic tests should be employed judiciously and be reserved for children who are most likely to derive measurable benefit, such as those likely to have peptic ulcer disease. At this time a test and treat strategy in children cannot be considered prudent, evidence based or cost effective. It is appropriate to limit diagnosis and treatment to children and adolescents in whom H pylori has been identified during endoscopic investigation.

Adolescent↗
PubMed2006

Diagnosing tuberculous pericarditis.

BACKGROUND: Definitive diagnosis of tuberculous pericarditis requires isolation of the tubercle bacillus from pericardial fluid, but isolating the organism is often difficult. AIM: To improve diagnostic efficiency for tuberculous pericarditis, using available tests. DESIGN: Prospective observational study. METHODS: Consecutive patients (n = 233) presenting with pericardial effusions underwent a predetermined diagnostic work-up. This included (i) clinical examination; (ii) pericardial fluid tests: biochemistry, microbiology, cytology, differential white blood cell (WBC) count, gamma interferon (IFN-gamma), adenosine deaminase (ADA) levels, polymerase chain reaction testing for Mycobacterium tuberculosis; (iii) HIV; (iv) sputum smear and culture; (v) blood biochemistry; and (vi) differential WBC count. A model was developed using 'classification and regression tree' analysis. The cut-off for the total diagnostic index (DI) was optimized using receiver operating characteristic (ROC) curves. RESULTS: Fever, night sweats, weight loss, serum globulin (>40 g/l) and peripheral blood leukocyte count (<10 x 10(9)/l) were independently predictive. The derived prediction model had 86% sensitivity and 84% specificity when applied to the study population. Pericardial fluid IFN-gamma >or=50 pg/ml, concentration had 92% sensitivity, 100% specificity and a positive predictive value (PPV) of 100% for the diagnosis of tuberculous pericarditis; pericardial fluid ADA >or=40 U/l had 87% sensitivity and 89% specificity. A diagnostic model including pericardial ADA, lymphocyte/neutrophil ratio, peripheral leukocyte count and HIV status had 96% sensitivity and 97% specificity; substituting pericardial IFN-gamma for ADA yielded 98% sensitivity and 100% specificity. DISCUSSION: Basic clinical and laboratory features can aid the diagnosis of tuberculous pericarditis. If available, pericardial IFN-gamma is the most useful diagnostic test. Otherwise we propose a prediction model that incorporates pericardial ADA and differential WBC counts.

Female↗
PubMed2005

Comparative assessment of blood and urine analyses in patients with acute poisonings by medical, narcotic substances and alcohol in clinical toxicology.

Acute poisonings by medical, narcotic substances and alcohol are actual in Russia in the recent years. Comparison of analytic facilities of modern analytical techniques: chromatographic (HPLC, GC, GC-MS) and immuno-chemical (FPIA) in clinical toxicology for urgent diagnostics, assessment of the severity of acute poisoning and the efficacy of the treatment in patients with acute poisonings by psychotropic drugs, narcotics and alcohol have been done. The object of the study were serum, blood, urine of 611 patients with acute poisonings by amitriptyline, clozapine, carbamazepine, opiates and also alcohol. Threshold concentrations (threshold, critical and lethal) of the toxicants and their active metabolites which corresponded to different degrees of poisoning severity have been determined. The most comfortable and informative screening method for express diagnostics and assessment of severity of acute poisonings by psychotropic drugs and narcotics showed the HPLC with using automatic analyzers. FPIA using the automatic analyzer could be applied for screening studies, if group identification is enough. GC-FID method is advisable in case of poisoning by medical substances and narcotics in view of repeated investigation for assessment of the efficacy of the therapy. GC-MS could be advisable for confirming the results of other methods. GC-TCD possess high sensitivity and specificity and is optimal for express differential diagnostics and quantitative assessment of acute poisoning by ethanol and other alcohols.

Acute Disease↗
PubMed1986

[Traumatology of the midface--diagnostic and therapeutic guidelines for the practicing ENT physician from the viewpoint of the ophthalmologist].

Fractures of the midface combined with orbital injuries endanger vision, binocular vision, and the lacrimal system. The best results of primary surgical management are advised if the surgeon adheres to a strict time schedule. For example, a perforating injury of the eye must be diagnosed as early as possible, and be repaired immediately. Otherwise, all manipulations necessary for reconstruction of the bone and soft tissue of the face worsen the condition of the opened eyeball, including loss of its contents and function. On the other hand, competent repair of the lacrimal system may be done at the end of the operation, and management of disordered eye mobility as seen in the "blow-out" fracture may sometimes be postponed for days or even weeks. The optimal chronological order of diagnostic and surgical management as seen from the ophthalmologist's view is given in tables, and discussed in detail.

Eye Injuries↗
PubMed2005

[Acute cholecystitis in combination with chronic hepatitis and cirrhosis of the liver].

An analysis of surgical treatment of cholelithiasis, acute cholecystitis was made which had appeared in 107 patients against the background of chronic diseases of the liver. Current diagnostic methods were used for differential diagnostics of jaundice: USI, CT, retrograde cholecystopancreatography, duodenoscopy. All the patients were operated upon against the background of hepatotropic and anti-ulcer therapy being performed. The main component of anesthesia during operation in most patients was epidural blockade which unlike multicomponent anesthesia had no negative effects on the indices of bilirubin in blood and aminotranspherase activity. Cholecystectomy, sanitation and decompression of bile ducts in patients with acute cholecystitis which appeared against the background of chronic lesion of the liver allowed to eliminate the source of portal toxemia, liquidate the mechanical source of cholestasis that, as a rule, results in liquidation of acute hepatic failure. The optimal method of differential diagnostics of jaundices was intraoperative cholangiography and choledochotomy.

Adult↗
PubMed1986

Diagnostic ultrasonography of equine limbs.

In our 3 years of clinical experience, we have found that diagnostic ultrasound provides the veterinarian with a valuable diagnostic tool. It allows the clinician to quantify morphologic change that has occurred as a result of soft-tissue injuries, even when the clinical findings are ambiguous or insufficient. In cases in which aggressive postinjury therapy has been instituted prior to presentation, diagnostic ultrasound is often the only noninvasive method that can ascertain the extent of the horse's injury. Diagnostic ultrasound provides the technology to detect injuries before they become permanently debilitating, because lesions as small as 1 mm in diameter can be detected. Prior to diagnostic ultrasound, the severity of many injuries was underestimated. In such cases, if the horse responded favorably to symptomatic therapy, the client would resume training. The result was often debilitation. Diagnostic ultrasound also enables the clinician to demonstrate visually to the client the location, size, and extent of lesions in the limb. One of the more gratifying effects of a sonographic study is the client's acceptance of the presence and extent of the injury after visualizing it. We have found that the old adage "a picture is worth a thousand words" is generally the rule in obtaining the proper course of therapy for the horse. The ability to make hard copies of sonograms enables the clinician to morphologically evaluate the rate of healing. He can accurately determine the effectiveness of a therapeutic regimen and ascertain when optimal healing has occurred. Diagnostic ultrasound can provide the researcher with an invaluable tool to document and quantify soft-tissue disease. We anticipate that, in the future, the sonographic appearance of recovered tissues will be correlated with new data on the healing process and the effectiveness of various therapies. The material presented above has covered the value of diagnostic ultrasound in major clinical situations related to equine lameness. Other applications, the discussion of which is beyond the scope of this article, include evaluation of the pastern for injuries to the SDF, DDF, and oblique sesamoidean ligament, and evaluation of the navicular bursae. Examination of muscles for hematomas, abscessations, and tears has also been accomplished ultrasonographically. Diagnostic ultrasound has facilitated study of the trochanteric and bicipital bursae, blood flow through arteries, and structures above the carpus and hock. Obviously, the clinical potential of diagnostic ultrasound is limitless.(ABSTRACT TRUNCATED AT 400 WORDS)

Abscess↗