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Results for “diagnostic optimization”

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At least 1,189 records · Page 66Linked to original sources
PubMed1984

[Programmed stimulation in patients with malignant ventricular arrhythmia. II: Individual optimization of anti-arrhythmia therapy].

The major purpose of programmed ventricular stimulation in patients with malignant ventricular arrhythmias (sustained ventricular tachycardia/ventricular fibrillation) is not the diagnostic or prognostic evaluation but the individual optimization of antiarrhythmic therapy. For successful antiarrhythmic treatment, the choice of an adequate parameter of efficacy is of outstanding relevance: in patients with frequent daily episodes of malignant ventricular arrhythmias, proper treatment can be based on Holter monitoring; however, in patients with infrequent but life-threatening attacks, Holter monitory appears to be inadequate and programmed stimulation is the method of choice for proper treatment decisions. A total of 394 serial pharmaco-electrophysiological studies was performed in 82 patients with inducible sustained ventricular tachycardia or ventricular fibrillation. During the acute serial studies, one drug was tested each subsequent day using short-term intravenous infusions. The only criterion for drug efficacy was prevention of inducible sustained ventricular tachycardia or ventricular fibrillation that had been reproducibly initiated under control conditions before antiarrhythmic treatment. At least one preventive drug was found in approximately 2/3rd of the patients. Following serial acute studies using intravenous administration, an effective agent was selected and given orally. Programmed stimulation was repeated usually after three days demonstrating reproducibility of preventive efficacy in 90% of the trials. During a subsequent follow-up period of an average of 15 months, the number of acute events (9%) including sudden death or life-threatening recurrences of malignant ventricular arrhythmias was significantly reduced as compared to patients with non-optimized therapy (54%; p less than 0.05). The number of cardiac deaths due to progressive heart failures was not significantly different in patients placed on optimized or non-optimized antiarrhythmic treatment.

Administration, Oral↗
PubMed2001

New immunoassay for the detection of Helicobacter pylori infection compared with urease test, 13C breath test and histology: validation in the primary care setting.

Helicobacter pylori plays a major role in peptic ulcer disease and, as a result, testing for H. pylori infection among patients with dyspepsia has often been advocated. The aim of the study was to determine the diagnostic accuracy, the analytical performance, and optimal cut-off point of a new serological assay, the Pyloriset EIA-G III for the detection of H. pylori infection in the primary care setting. For 113 primary care patients with dyspepsia urea breath test, CLO test, histology and serology tests were performed. Diagnostic accuracy of the Pyloriset EIA-G III was evaluated against a reference standard of a carbon urea breath test (CUBT), CLO test and histology (from gastric biopsies). Precision, linearity and correlation of the serological assay with the CUBT and former Pyloriset were also determined. At the optimal cut-off level of 40 U/ml, the positive predictive value was 92.1%, negative predictive value 96.3%, sensitivity 87.5%, and specificity 93.9%. The within-run precision was high. The recovery data were good. The correlation of both CUBT and the former Pyloriset EIA-G and the Pyloriset EIA-G III was high. At the cut-off level of 40 U/ml, the new Pyloriset EIA-G III is a reliable method to detect H. pylori infection in the primary care setting.

Adult↗
PubMed2001

The utility and potential cost-effectiveness of stress myocardial perfusion thallium SPECT imaging in hospitalized patients with chest pain and normal or non-diagnostic electrocardiogram.

BACKGROUND: The evaluation of hospitalized patients with chest pain and non-diagnostic electrocardiogram is problematic and the optimal cost-effective strategy for their management controversial. OBJECTIVES: To determine the utility of myocardial perfusion imaging with thallium-201 for predicting outcome of hospitalized patients with chest pain and a normal or non-diagnostic ECG. METHODS: On pain cessation, 109 hospitalized patients, age 61 +/- 14 years (mean +/- SD), with chest pain and non-diagnostic ECG underwent stress myocardial perfusion SPECT imaging with thallium-201. Costs related to their management were calculated. The occurrence of non-fatal myocardial infarction or cardiac death was recorded at 12 +/- 5 months follow-up. RESULTS: A normal SPECT was found in 84 patients (77%). During one year follow-up, only 1 (1.2%) compared to 7 (28%) cardiac events (6 myocardial infarctions, 1 cardiac death) occurred in patients with normal versus abnormal scans respectively (P < 0.0001). Negative predictive value and accuracy of the method were 99% and 83% respectively. Multivariate regression analysis identified an abnormal SPECT as the only independent predictor of adverse cardiac event (P = 0.0016). Total cost from admission until discharge was 11,193 vs. 31,079 shekels (P < 0.0001) for normal and abnormal scan. Considering its high negative predictive value, shortening the hospital stay from admission until scan performance to 2 days would result in considerably reduced management costs (from NIS 11,193 to 7,243) per patient. CONCLUSION: Stress SPECT applied to hospitalized patients with chest pain and a normal or non-diagnostic ECG is safe, highly accurate and potentially cost effective in distinguishing between low and high risk patients.

Aged↗
PubMed1997

Technical considerations for optimal orthopedic imaging.

Over the past 25 years bone scintigraphy has played an essential role in most Nuclear Medicine departments, accounting for 25% to 60% of the patient volumes. No longer is every bone scan ordered as part of a metastatic workup. Today radionuclide bone imaging (RNBI) is included in most orthopedic diagnostic pathways. It is necessary to optimize the bone scan procedure to be sensitive, to carefully localize abnormal uptake for diagnosis, to correlate the bone scans, plain radiographs, computed tomographic (CT) scans, and magnetic resonance (MR) scans that accompany the patient, and to be precise in reporting a final impression. This can be done through meticulous attention to the image acquisition so that it encompasses not only equipment specifications and acquisition parameters, but also patient history, preparation, imaging protocols, positioning, and image correlation. The importance of these considerations, the rationale to explain them, and suggested guidelines for their implementation will be discussed in this article.

Bone Diseases↗
PubMed1996

MR pancreatography: technique and applications.

Magnetic resonance cholangiopancreatography (MRCP) is a diagnostic method that uses three-dimensional data sets for projection images, as well as arbitrary cross-sectional images, of the pancreatic ducts. The method is simple, not uncomfortable, and requires no contrast media. Magnetic resonance cholangiopancreatography (MRCP) was initially developed as a substitute for ERCP for diagnosis of pancreatic disorders such as neoplasm and chronic pancreatitis, but the method offers advantages other than safety and flexibility. MRCP may be the diagnostic method of choice when ERCP is contraindicated or fails. Imaging after injection of secretin may add functional information to MRCP that may reflect one aspect of pancreatic exocrine physiology. Adequate diagnostic evaluation of acute pancreatitis, pancreatic trauma, and mucinous ductal ectasia may also be feasible. Innovations such as fast sequences with breath-holding, receiver multicoils, high-power gradient systems, and postprocessing will further refine the technique. Optimized MRCP could limit indications for diagnostic endoscopic pancreatography substantially.

Fourier Analysis↗
PubMed2001

Diagnostic imaging of lameness in small animals.

The demand for advanced diagnostic imaging procedures such as nuclear scintigraphy, ultrasonography, computed tomography, and magnetic resonance imaging has increased dramatically over the past 10 years. Veterinarians, seeking to improve their diagnostic capabilities and clients willing to pursue "best medicine" have driven this demand, resulting in installation of advanced imaging facilities at most academic and private referral practices. Knowledge of potential benefits of various modalities will allow the veterinarian to optimize his or her use of diagnostic imaging in his or her own practice or in a referral practice.

Animals↗
PubMed1998

[High-resolution volumetric computerized tomography of the lung: optimization of technique and image quality as a function of its clinical-diagnostic use and dose to the patient].

PURPOSE: The aim of this project was to analyze and validate the diagnostic applications of Volumetric High Resolution CT in the study of focal or diffuse infiltrative lung disease compared with High Resolution CT. To date HRCT is the gold standard in the assessment of infiltrative lung diseases, but it shows some limitations such as artifacts due to both respiratory and cardiac motions, as well as the need for multiple breath-holds. MATERIAL AND METHODS: September, 1996, to September, 1997, anthropomorphic test phantoms and a group of 34 subjects (8 without lung disease and 26 with aspecific lung disease: TBC, BPCO, micronodular conditions, cardiogenic interstitial pulmonary edema) were submitted to both HRCT and VHRCT. VHRCT was carried out with a 3-mm slab thickness and the images were reconstructed with a 1-mm interval and processed with MIP and MinIP reconstructions. With both techniques we compared some physical parameters (slice sensitivity profile, noise, longitudinal resolution) and some radiographic findings (central and peripheral airways lumen, peripheral vessels, nodular and interstitial abnormalities, emphysema foci, focal areas of ground glass pattern and bronchiectasis). We calculated the radiation exposure dose of both HRCT and VHRCT, also testing a low-dose protocol. RESULTS: The analysis of physical parameters showed no major differences between HRCT and VHRCT regarding longitudinal resolution, while minimal advantages were found with HRCT for slice sensitivity profile and image noise. Radiographic analysis showed additional findings in 27% of patients with nodular disease using VHRCT-MIP in 8% of patients with emphysema and 25% of cases with focal areas of ground glass opacities, using VHRCT-MinIP. Relative to HRCT findings, VHRCT better depicted all patterns but subpleural nodules. The surface radiation dose was 2.8 times higher with VHRCT than HRCT. It is possible to halve radiation exposure using a low dose protocol (120 kV, 110-150 mA). CONCLUSIONS: Our study provides conclusive results concerning the use of VHRCT with standard technical parameters because this technique showed some advantages in the study of a wide range of diffuse or focal lung diseases. We suggest that this protocol be applied only in patients with mild forms of lung disease or in the cases of difficult interpretation, such as suspicious abnormal areas at HRCT, because its doses are higher. Out low-dose protocol is currently on trial but we expect promising results.

Evaluation Studies as Topic↗
PubMed1999

A prospective multicenter trial evaluating diagnostic validity of multivariate analysis and individual serum marker in differential diagnosis of pancreatic cancer from benign pancreatic diseases.

CONCLUSION: A multivariate analysis of CAMPAS-PX2 can increase its diagnostic accuracy in differential diagnosis of pancreatic cancer from benign pancreatic or extrapancreatic disease, when compared with CA19-9 alone. However, the improvement in diagnostic accuracy is still not satisfactory in spite of an elaborate combination of serum markers in diagnosis for pancreatic cancer. Optimal combination of a sensitive serum marker and another diagnostic modality, such as ultrasonography, can be a practical way to improve important diagnostic and cost-effectiveness in diagnosis for pancreatic cancer. BACKGROUND: No specific biological test has yet been developed for diagnosis of pancreatic cancer, although increasing numbers of tumor markers become available. For improvement in the diagnostic and cost effectiveness, it is important to select optimal combination of several serum markers relatively independent of each other. METHODS: A new model of discriminant function, computer-aided multivariate and pattern analysis system for pancreatic cancer examination 2 (CAMPAS-PX2), was developed based on the data of the 23 serum tumor markers from the first prospective trial (1) to differentiate between pancreatic cancer and benign pancreatobiliary disease by logistic regression analysis using a stepwise selection method. In 243 patients suspected of having pancreatic pancreatic cancer by a multicenter prospective study, the diagnostic value of the multivariate analysis, CAMPAS-PX2, was compared with the 23 markers. RESULTS: Pancreatic cancer was subsequently identified in 27 patients. Positive in disease, negative in health, and area under receiver operating characteristic curve were significantly higher by CAMPAS-PX2 (89, 87, 91%) than by CA 19-9 (78, 82, 84%), the most sensitive marker among the 23 markers.

Biomarkers, Tumor↗
PubMedDate not supplied

Epidemiological perspectives for the development of future diagnostic systems.

Three uses of epidemiological data for diagnostic revisions are suggested. (1) Psychometric analysis of community cases over the full spectrum of symptom severity can help determine whether true discrete disease entities underlie particular symptom profiles. (2) Analysis of external validators in community samples can help select optimal cut-points for defining diagnostic criteria. (3) Clinical epidemiological studies can provide quick and comparatively inexpensive preliminary checks, prior to carrying out expensive experimental treatment trials, on the plausibility of proposed subtyping distinctions based on nonexperimental evidence regarding differential treatment response. Correction of a number of basic conceptual and methodological flaws that have hampered previous studies would allow epidemiological research of these three sorts to play a much more important part in future diagnostic revisions than they have in past revisions.

Epidemiologic Research Design↗
PubMed2006

[Evaluation of the diagnostic significance of cytologic studies in pancreatic tumors].

The study was undertaken to specify cytomorphological criteria for prostatic duct adenocarcinoma (PDAC), by assessing fine-needle aspiration biopsy (FNAB) specimens. Histologically verified cases were selected and the archival cytological material that constituted Leishman stained smears obtained by percutaneous FNAB under ultrasound guidance from 72 patients with PDAC (n = 50) or ductal hyperplasia (DP) (n = 22) was revised. For statistical analysis, the authors selected the following cytological signs of malignancy: anisonucleosis, increased nuclei, hyperchromia, uneven chromatin distribution, enucleation, uneven nuclear outline, apocytes; increased nucleoli, nucleolar polymorphism, multiple nucleoli, increased cells, anisocytosis (polymorphism of the size and shape of a cell, mitoses, piled nuclei, papillary structures, slightly glandular structures. The statistical analysis identified three most important cytological criteria for PDAC: anisocytosis, anisonucleosis, and piled nuclei. Keeping in mind all three signs at once increases the probability of detecting of PDAC up with 90%. The detection of only anisocytosis in the cytological specimen showed a 40% probability of the presence of PDAC. Three additional cytological signs of PDAC were also identified: increased nuclei, uneven nuclear outline, and slightly adhesive structures. The probability of PDAC was 100% if the specimen contained three most significant signs and any of the additional signs. By taking into account the indicators of diagnostic efficiency (DE), the best criteria were as follows: anisonucleosis, uneven nuclear outline, anisocytosis. The optimal indicators of DE for anisonucleosis were 95.83% diagnostic sensitivity (DSen), 95.83% diagnostic specificity (DSp), and 95.83% DE. When two indicators (anisonucleosis and uneven nuclear outline) were simultaneously used, DSen was 93.42; DSp, 98.53% (the highest); DE, 95.83%. Thus, the following cytological signs are defined as important for differentiation of PH and PDAC: anisocytosis, anisonucleosis, piled nuclei, increased nuclei, uneven nuclear outline, slightly adhesive structures.

Adenocarcinoma↗
PubMed2005

New diagnostic techniques.

OBJECTIVES: To review current diagnostic strategies. To review alternative diagnostic techniques. RESULTS: The pathogen(s) responsible for onychomycosis must be identified to optimize treatment. Mycological examination is currently the most common diagnostic technique. This typically involves clearing with potassium hydroxide followed by microscopy. This direct test rapidly differentiates between living and dead hyphae. Sensitivity can be enhanced by using dimethyl sulfoxide (DMSO) or stains such as Chlorazol Black E. However, microscopy must always be combined with culture, allowing correct species identification. Accurate diagnosis depends on the expertise of laboratory staff and biologists and on the quality of the nail sample: samples should always be taken from the most proximal infected area. In the absence of experienced mycological laboratories, new laboratory techniques have been developed. Histological analysis by nail plate clipping has been shown to be an easy and efficient method for diagnosis. However, nail clipping is not an optimal technique for fungal culture and a large proportion of nonpathogenic but contaminant moulds can grow on culture medium. Moreover, histological analysis provides no information about causal agent or vitality. In vivo confocal microscopy and flow cytometry are powerful but complicated and costly techniques, making them unsuitable for routine use. Finally, polymerase chain reaction (PCR) (low proportion of positive results) and PCR-restriction fragment length polymorphism (PCR-RFLP) (suitable even for patients receiving antifungals) techniques have been developed. These molecular methods are cost-intensive and require highly skilled staff, meaning they are reserved exclusively for laboratories that process numerous nail samples. CONCLUSION: In conclusion, mycological examination remains the gold standard technique; it provides the most information, at a reasonable cost with little inconvenience to the patient.

DNA, Fungal↗
PubMed2006

Katrina, the tsunami, and point-of-care testing: optimizing rapid response diagnosis in disasters.

We assessed how point-of-care testing (POCT), diagnostic testing at or near the site of patient care, can optimize diagnosis, triage, and patient monitoring during disasters. We surveyed 4 primary care units (PCUs) and 10 hospitals in provinces hit hardest by the tsunami in Thailand and 22 hospitals in Katrina-affected areas. We assessed POCT, critical care testing, critical values notification, demographics, and disaster responses. Limited availability and poor organization severely limited POCT use. The tsunami impacted 48 PCUs plus island and province hospitals, which lacked adequate diagnostic instruments. Sudden overload of critical victims and transportation failures caused excessive mortality. In New Orleans, LA, flooding hindered rescue teams that could have been POCT-equipped. US sea, land, and airborne rescue brought POCT instruments closer to flooded areas. Katrina demonstrated POCT value in disaster responses. We recommend handheld POCT, airborne critical care testing, and disaster-specific mobile medical units in small-world networks worldwide.

Diagnosis↗
PubMed1986

High-resolution magnetic resonance imaging of the ankle: normal anatomy.

An imaging-anatomic correlative study of ankle anatomy based upon six healthy adults and six fresh cadaveric specimens was performed to evaluate the diagnostic capabilities of magnetic resonance imaging (MRI). Optimal pulsing sequences and imaging planes for various structures of interest were established. MRI afforded exquisite depiction of anatomic detail, particularly the diagnostically important collateral ligaments. Limitations in the ability to delineate the joint capsule and articular cartilage were documented, with the former detectable only on T2 weighted images in the presence of synovial fluid.

Adult↗
PubMed1978

Problems of spectrum and bias in evaluating the efficacy of diagnostic tests.

To determine why many diagnostic tests have proved to be valueless after optimistic introduction into medical practice, we reviewed a series of investigations and identified two major problems that can cause erroneous statistical results for the "sensitivity" and "specificity" indexes of diagnostic efficacy. Unless an appropriately broad spectrum is chosen for the diseased and nondiseased patients who comprise the study population, the diagnostic test may receive falsely high values for its "rule-in" and "rule-out" performances. Unless the interpretation of the test and the establishment of the true diagnosis are done independently, bias may falsely elevate the test's efficacy. Avoidance of these problems might have prevented the early optimism and subsequent disillusionment with the diagnostic value of two selected examples: the carcinoembryonic antigen and nitro-blue tetrazolium tests.

Bacterial Infections↗
PubMed2004

[Right ventricular arrhythmias].

Right ventricular arrhythmias predominantly occur in young patients with rare cardiac diseases. Underlying cardiac conditions include idiopathic right ventricular outflow-tract tachycardia (RVOT-VT), arrhythmogenic right ventricular cardiomyopathy (ARVC), Brugada syndrome, and postoperative congenital heart disease (i.e. tetralogy of Fallot). According to the underlying cardiac disease, there are significant differences in the diagnostic and therapeutic management and prognosis which is mainly determined by life-threatening ventricular arrhythmia recurrences and sudden cardiac death. To provide optimal treatment for affected patients, a detailed diagnostic evaluation and risk stratification is mandatory. Tailored treatment strategies aim at the suppression or effective termination of recurrent ventricular tachyarrhythmias and prevention of sudden death by antiarrhythmic drug therapy, catheter ablation, and the implantation of cardioverter-defibrillators. This review summarizes the current knowledge on pathogenesis, diagnosis, treatment and prognosis of those conditions that are associated with arrhythmias originating from the right ventricle.

Arrhythmias, Cardiac↗
PubMed1981

Ranking diagnostic protocols--a proposed process based on use of the nine-cell diagnostic decision matrix.

A process for ranking competing diagnostic protocols for a specific disease is presented. The process incorporates the basic principles of medical decision making, and provides for the consideration of equivocal test results as well as results for patients who have ill-defined or incompletely defined disease. It provides a means for developing an a priori optimization process prior to ranking competing diagnostic algorithms. Methods for transferring ranking information among populations with widely differing disease prevalences are given.

Clinical Laboratory Techniques↗
PubMed1986

Comparison of thyrotropin assays by relative operating characteristic analysis.

We compared two versions of a commercial double-site immunoradiometric assay for human thyrotropin, one of them claimed to show superior ability in apportioning euthyroid and hyperthyroid populations. Relative operating characteristic (ROC) analysis permits the calculation of the area under the ROC curve as an unbiased unit measure of diagnostic validity, and also yields an optimal decision point for separating the two populations, based on relative prevalences and locally perceived utilities of test outcomes. We examined 48 hyperthyroid and 50 euthyroid subjects with the original assay and with a later version from the same manufacturer and conclude that the latter demonstrates a small but significant superiority in diagnostic performance throughout the clinical range of interest. Furthermore, peak diagnostic efficacy is attained when the boundary between the two populations is set at 0.3 mIU/L. At this decision point, sensitivity is 58%, specificity is 96%, and the predictive value of a positive test is 75%.

Adult↗
PubMed2004

The primary care physician's approach to congenital anomalies.

Children with congenital anomalies often represent a special diagnostic and management challenge. To provide optimal care for these children, one must employ a systematic approach to identify the likely pathogenic mechanism leading to the birth defects present. Determining how distinct anomalies relate to one another may lead to elucidation of a specific genetic etiology for the patient's condition. Genetic testing is increasingly available to allow for diagnostic confirmation. Using this systematic approach to a child with congenital anomalies permits accurate prognostic and recurrence risk counseling, informed management decisions, and the appropriate allocation of social support and medical resources.

Abnormalities, Multiple↗