[Optimization of the diagnostic and treatment methods in chronic heart failure and the characteristics of its pharmacotherapy under alpine conditions].
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Adult↗
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Results for “diagnostic optimization”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
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[Active diagnostic tactics for optimizing the treatment of acute cholecystitis].
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Acute Disease↗
[Dental radiography: its optimization as a diagnostic method].
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Humans↗
Optimizing immunohistochemistry in diagnostic tumor pathology with antigen retrieval.
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Adult↗
[Reduction of NMR image artefacts by using optimal materials as diagnostic aids and implants].
Differences in magnetic susceptibility, as occur for example at the boundary between implant materials and the surrounding body tissue, result in artefacts and a signal loss in magnetic resonance imaging. By using materials with a magnetic susceptibility matched to the respective environment, it is possible to minimize both artefacts and signal loss. Such materials can be made by combining two materials of different magnetic susceptibility (e.g. diamagnetic and paramagnetic materials) in such a way that the resulting material has the desired effective magnetic susceptibility.
Artifacts↗
Assessing diagnostic tests once an optimal cutoff point has been selected.
The specificity and sensitivity of a quantitative diagnostic test depends on the chosen cutoff point. The common practice of selecting a cutoff point that maximizes the specificity plus the sensitivity, as judged from the observed test results, is studied here by simulation. Test performance is on average assessed too optimistically by this procedure--a phenomenon of importance when sample sizes are small. For example, the average positive bias is up to 15% of the test performance for sample sizes of 25. Furthermore, binomial calculated standard errors of specificity and sensitivity estimates are incorrect. A Monte Carlo statistical method--the "bootstrap procedure"--is applied to correct for bias and to estimate standard errors, including the standard error of the optimal cutoff point. Independent and paired comparisons of two diagnostic tests are also considered when optimal cutoff points have been selected. For this purpose, binomial statistical tests behave satisfactorily. Examples of power functions are presented.
Bile Acids and Salts↗
Measurement of the clinical and cost-effectiveness of non-invasive diagnostic testing strategies for deep vein thrombosis.
OBJECTIVES: To estimate the diagnostic accuracy of non-invasive tests for proximal deep vein thrombosis (DVT) and isolated calf DVT, in patients with clinically suspected DVT or high-risk asymptomatic patients, and identify factors associated with variation in diagnostic performance. Also to identify practical diagnostic algorithms for DVT, and estimate the diagnostic accuracy, clinical effectiveness and cost-effectiveness of each. DATA SOURCES: Electronic databases (to April 2004). A postal survey of hospitals in the UK. REVIEW METHODS: Selected studies were assessed against validated criteria. A postal survey of hospitals in the UK was undertaken to describe current practice and availability of tests, and identify additional diagnostic algorithms. Pooled estimates of sensitivity, specificity and likelihood ratios were obtained for each test using random effects meta-analysis. The effect of study-level covariates was explored using random effects metaregression. A decision-analytic model was used to combine estimates from the meta-analysis and estimate the diagnostic performance of each algorithm in a theoretical population of outpatients with suspected DVT. The net benefit of using each algorithm was estimated from a health service perspective, using cost--utility analysis, assuming thresholds of willingness to pay of pound 20,000 and pound 30,000 per quality-adjusted life-year (QALY). The model was analysed probabilistically and cost-effectiveness acceptability curves were generated to reflect uncertainty in estimated cost-effectiveness. RESULTS: Individual clinical features are of limited diagnostic value, with most likelihood ratios being close to 1. Wells clinical probability score stratifies proximal, but not distal, DVT into high-, intermediate- and low-risk categories. Unstructured clinical assessment by experienced clinicians may have similar performance to Wells score. In patients with clinically suspected DVT, D-dimer has 91% sensitivity and 55% specificity for DVT, although performance varies substantially between assays and populations. D-dimer specificity is dependent on pretest clinical probability, being higher in patients with a low clinical probability of DVT. Plethysmography and rheography techniques have modest sensitivity for proximal DVT, poor sensitivity for distal DVT, and modest specificity. Ultrasound has 94% sensitivity for proximal DVT, 64% sensitivity for distal DVT and 94% specificity. Computed tomography scanning has 95% sensitivity for all DVT (proximal and distal combined) and 97% specificity. Magnetic resonance imaging has 92% sensitivity for all DVT and 95% specificity. The diagnostic performance of all tests is worse in asymptomatic patients. The most cost-effective algorithm discharged patients with a low Wells score and negative D-dimer without further testing, and then used plethysmography alongside ultrasound, with venography in selected cases, to diagnose the remaining patients. However, the cost-effectiveness of this algorithm was dependent on assumptions of test independence being met and the ability to provide plethysmography at relatively low cost. Availability of plethysmography and venography is currently limited at most UK hospitals, so implementation would involve considerable reorganisation of services. Two algorithms were identified that offered high net benefit and would be feasible in most hospitals without substantial reorganisation of services. Both involved using a combination of Wells score, D-dimer and above-knee ultrasound. For thresholds of willingness to pay of pound 10,000 or pound 20,000 per QALY the optimal strategy involved discharging patients with a low or intermediate Wells score and negative D-dimer, ultrasound for those with a high score or positive D-dimer, and repeat scanning for those with positive D-dimer and a high Wells score, but negative initial scan. For thresholds of pound 30,000 or more a similar strategy, but involving repeat ultrasound for all those with a negative initial scan, was optimal. CONCLUSIONS: Diagnostic algorithms based on a combination of Wells score, D-dimer and ultrasound (with repeat if negative) are feasible at most UK hospitals and are among the most cost-effective. Use of repeat scanning depends on the threshold for willingness to pay for health gain. Further diagnostic testing for patients with a low Wells score and negative D-dimer is unlikely to represent a cost-effective use of resources. Recommendations for research include the evaluation of the costs and outcomes of using the optimal diagnostic algorithms in routine practice, the development and evaluation of algorithms appropriate for specific groups of patients with suspected DVT, such as intravenous drug abusers, pregnant patients and those with previous DVT, the evaluation of the role of plethysmography: interaction with other diagnostic tests, outcome of low-risk patients with negative plethysmography and measurement of the costs of providing plethysmography, and methodological research into the incorporation of meta-analytic data into decision-analytic modelling.
Adult↗
Discriminant factor analysis of 31P NMR spectroscopic data in myopathies.
Discriminant factor analysis (DFA) enables one to distinguish among diagnostic groups using diagnostic variables. It provides discriminant functions that are linear combinations of the diagnostic variables and that optimally separate diagnostic groups. It was used to enhance the accuracy of 31P NMR data in the diagnosis of myopathies. DFA allowed a good separation of normal subjects, congenital neuromuscular disorders with type I fiber predominance, and McArdle's diseases. It elicited an unexpected homogeneity of idiopathic rhabdomyolyses, the metabolic origin of which is unknown, and suggested that the abnormality could involve the mitochondrial oxidative metabolism in some of them. In mitochondrial myopathies, an expected heterogeneity is shown by DFA. It may allow an automatic diagnosis of some myopathies from 31P NMR data or guide biochemists by comparing biochemical features of a new patient to those of previously established groups.
Adult↗
Xeroradiography in root fracture diagnosis.
Root fracture is a clinical problem that often is difficult to diagnose. The purpose of this study was to compare diagnostic value of conventional radiographic and xeroradiographic images of experimentally fractured teeth. Forty-five extracted human single-rooted teeth were used. The roots of the teeth were coated with wax to simulate periodontal ligament and invested in acrylic to the cementoenamel junction. An access cavity was prepared and para-post, size 4 to 12 mm, was placed into the root canal. Each tooth with post was placed on the load cell table of an Instron testing machine. The Instron continuously recorded load on a moving graph paper. The load was increased until the tooth fractured. Determination of fracture was made by the sound of a sharp "crack" and by a sudden release of load on the post, as seen on the Instron recording graph. After fracture, conventional radiograph and xeroradiograph were obtained for each tooth by use of the paralleling technique. The x-ray beam angle, film distance, and tooth placement were held constant in both techniques by use of a Rinn instrument. All films were evaluated by use of light from a masked viewbox, while all of the xeroradiographs were viewed in reflected light. A magnifying glass was used to aid in the examination process. The samples were examined and categorized for root fracture by the examiners with the use of the following scores: 0 = unacceptably poor, 1 = poor but diagnostic, 2 = adequate for diagnostic information, and 3 = optimal for diagnostic information.(ABSTRACT TRUNCATED AT 250 WORDS)
Dental Stress Analysis↗
A comparison between xeroradiography and conventional radiography in the diagnosis of endodontic lesions.
Detection of periapical bone pathosis is an important part of the diagnostic process in dentistry. Xeroradiographs and E-speed films were taken to evaluate and to compare the diagnostic value for the radiographic interpretation of periapical lesions. Thirty-four patients undergoing endodontic treatment were chosen. Simultaneous exposures of the radiographic film and the xeroradiographic plates were made. The samples were viewed and categorized by the examiners using the following scores: 0 = unacceptably poor, 1 = poor but diagnostic, 2 = adequate for diagnostic information, and 3 = optimal for diagnostic information. A paired sample t test was performed on the result of the evaluation by the two examiners, and both showed that there were no significant difference at p less than 0.05 between xeroradiography and conventional radiography. A two-sample t test was performed on the means of the two examiner's evaluation, and there was no significant difference at p less than 0.05 between the means.
Alveolar Process↗
Pitfalls in establishing the diagnosis of deep venous thrombophlebitis by indium-111 platelet scintigraphy.
Forty-seven 111In-platelet scintigraphs (In-PS) were analyzed retrospectively to identify sources of diagnostic error and to optimize the diagnostic criteria for active deep venous thrombophlebitis (DVT). The results of In-PS were compared with contrast venography, additional diagnostic studies, and clinical outcome. Three patterns of platelet localization emerged as the best predictors of active DVT: (a) focal or (b) linear 4-hr localization, or (c) an asymmetric blood-pool pattern on 4-hr imaging that evolved into a focal or linear pattern by 16 to 24 hr. All false-positive studies had abnormal patterns confined to the inguinal region at 24 hr. All patients with false-negative studies had received heparin between 4 and 24 hr. The potential pitfalls encountered in the evaluation of the iliac, femoral, and popliteal veins are reviewed and the importance of delayed imaging in selected cases is emphasized.
Blood Platelets↗
Monte Carlo study of grid performance in diagnostic radiology: task dependent optimization for screen-film imaging.
An optimization of anti-scatter grid design using Monte Carlo techniques in diagnostic radiology is presented. The criterion for optimization was to find the combinations of the grid parameters (lead strip width, grid ratio and strip density) and tube potential which result in the lowest mean absorbed dose in the patient at fixed image contrast. The optimization was performed in three irradiation geometries, representing different scattering conditions (paediatric examinations, and two adult lumbar spine examinations) and was restricted to grids using fibre materials in covers and interspaces. Grid designs currently available were studied, as were designs which use thinner strips (< 30 microns) and higher grid ratios (> 18). It was found that grids with widely different strip densities (strips cm-1) and grid ratios can have good performance provided that they are used with appropriate strip width and tube potential. With increasing amounts of scatter, the optimal grid requires thicker strips and higher grid ratios. Increasing the strip density and using thinner strips and higher grid ratios are generally required. Grids with low strip density (25 strips cm-1) were found to be less sensitive to alterations in strip width. Optimal grids for paediatric radiology require thinner strips (10-20 microns) than those in currently available grids. Grids on the market are best suited for examinations of the adult body in anteroposterior (AP) view. In the adult lateral view, representing the largest scattering volume, higher grid ratios (> 18) than those in existing grids would be optimal. Examples of good grid designs are given for each examination.
Adult↗
[Diagnostic, prognostic and therapeutic optimization in oncology. XIIth Grenoble Oncology meeting. 30-31 March 1995].
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Animals↗
Utility of thin-layer preparations in thyroid fine-needle aspiration: diagnostic accuracy, cytomorphology, and optimal sample preparation.
BACKGROUND: The efficacy of preparing thyroid fine-needle aspirations (FNAs) as thin-layer slides has not been evaluated extensively. METHODS: To evaluate the efficacy of thin-layer cytology, the authors examined thyroid FNAs from 135 unselected palpable lesions that were aspirated using uniform procedures and prepared as air-dried, Diff-Quik-stained direct smears (DS) and Papanicolaou-stained thin-layer slides (TL). Diagnoses rendered independently on masked slides from each thyroid nodule were compared with the reported final cytologic or histologic diagnoses based on all available pathologic material. Slides were analyzed for diagnostically important cytologic features and the optimal number of TL slides per sample was assessed. RESULTS: TL diagnoses agreed with final diagnoses in 85% of cases compared with 96% for DS. All 11 neoplasms were recognized in both preparations. A final diagnosis of chronic lymphocytic thyroiditis (CLT) was missed in 10 of 26 TL (39%) compared with 2 of 26 DS (8%) (P = 0.013, McNemar's test). Cytologic features appreciated less often in TL than DS (McNemar's test) included diffuse colloid, spherules, tissue fragments, and lymphocytes. Multinucleated giant cells were identified more often in TL than DS. Two TL slides were sufficient for diagnosis in 83% of cases. CONCLUSIONS: The diagnostic accuracy of TL was 85% compared with 96% for DS. CLT was diagnosed accurately in 62% of TL compared with 92% of DS. Cytologic features in TL and DS may differ. Preparation of only two TL slides is adequate for definitive diagnosis in most cases.
Biopsy, Needle↗
The current and future status of critical care testing and patient monitoring.
Ex vivo and in vivo biosensor-based systems for patient monitoring now augment in vitro point-of-care testing, a paradigm currently in the explosive phase. As new technologies arise, so do opportunities for laboratory professionals. First, the laboratory consultant or clinical pathologist can contribute substantially to our understanding of temporal optimization and the role of diagnostic testing in optimizing diagnostic-therapeutic processes. Clarification of these facilitates wise selection of alternative testing modalities, test clusters, and instrument formats. Second, the laboratory professional is a natural member of a performance team that can help optimize outcomes and assure the quality of point-of-care testing. Explicit site-specific performance criteria for accuracy, precision, response time, and test clusters are essential and can only be established and accomplished jointly with clinicians. Third, clinical integration requires practice guidelines and care paths. These can help determine how, when, and where point-of-care testing should be implemented. Finally, global outcomes optimization calls for the input of those professionals who are most familiar with the economics of diagnostic testing, the challenges of point-of-care testing, and the best clinical benefits of in vitro, ex vivo, and in vivo biosensor-based systems in critical care and other settings.
Biosensing Techniques↗
Main problems of modern medicine in diagnostics and learning: ways of optimal solution.
OBJECTIVE: 1. Selecting the key problems in medicine--I. Diagnostic problems, II. Didactic and training problems of medical education, III. Economical problems, IV. Communications technologies problems, V. Psychological problems, VI. Social problems, VII. Strategic problems. 2. Outline ways to optimal solution of these problems. METHODS: Innovative intellectual approach to medical diagnostic decision-making has been suggested. Knowledge levels and didactic systems, its limitations have been described. The methodologies and computerized technologies are tools to overcome the obstacles. RESULTS: Series of didactic experiments were carried out with the purpose to evaluate comparatively conventional and offered innovative methods of diagnostics and professional training shows significant advantages of the innovations. CONCLUSION: The above mentioned problems can be solved successfully by computerized diagnostics based on algorithmical evidence-based approach to disease recognizing, and mass professional education mainly based on eLearning.
Algorithms↗
Optimizing REM latency as a diagnostic test for depression using receiver operating characteristic analysis and information theory.
New diagnostic techniques must be evaluated for their intrinsic accuracy and for their applicability to particular patient groups in specific clinical settings. Using receiver operating characteristic (ROC) analysis and concepts from information theory, we have developed a new mathematical and graphical method that can evaluate, compare, and optimize the performance of diagnostic tests for any value of disorder prevalence. Our analytic method is appropriate to any test that sorts disordered from nondisordered subjects using a continuous or nonbinary diagnostic variable; its characterization of the fundamental properties of such tests thus has important implications for the evaluation and optimization of diagnostic modalities used by clinicians in all medical specialties. We demonstrate our method using published data from five studies that used sleep architecture as a "biological marker" for depression. Our analysis confirms that REM latency is comparable to the dexamethasone suppression test in its ability to discriminate depressed from control subjects. For each of the five studies, we show how optimal REM latency cut-off times may be selected so that diagnostic information yield is maximized, and we compare the ability of each study to detect depressed subjects in populations where the prevalence of affective disorder can be specified.
Adult↗
Acute mesenteric venous thrombosis following laparoscopic Roux-en-Y gastric bypass.
BACKGROUND AND OBJECTIVES: Acute mesenteric venous thrombosis has not been previously reported as a complication following Roux-en-Y gastric bypass. METHODS: The authors present 3 cases from a single-center experience of over 1500 patients as well as a review of the literature. RESULTS: The presenting symptoms are nonspecific, and the diagnosis is often made after infarction of the intestine has occurred. A high index of clinical suspicion is required for timely diagnosis and treatment. A computed tomography scan combined with diagnostic laparoscopy are the gold standard diagnostic tests, and early anticoagulation is the optimal treatment. Diagnostic laparoscopy is essential to evaluate the degree of bowel ischemia and the need for resection. CONCLUSION: Acute mesenteric venous thrombosis following Roux-en-Y gastric bypass is a severe and potentially life-threatening complication that requires early exploration and anticoagulation.
Acute Disease↗