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PubMed1983

[Comparative roentgen study of the small intestine with single and double contrast].

The experiences from a total of 303 small intestine examinations of different techniques show that especially the double-contrast representation using barium sulfate and air achieves the best diagnostical findings. The double-contrast representation can be achieved by an antegrade small intestine enema (enteroclysis) or within the conventional small intestine passage by retrograde air insufflation. These examination techniques make optimal fine diagnostics especially of the lower ileum possible. The indications for the different methods are explained.

Air↗

PubMed2006

Bayesian multivariate hierarchical transformation models for ROC analysis.

A Bayesian multivariate hierarchical transformation model (BMHTM) is developed for receiver operating characteristic (ROC) curve analysis based on clustered continuous diagnostic outcome data with covariates. Two special features of this model are that it incorporates non-linear monotone transformations of the outcomes and that multiple correlated outcomes may be analysed. The mean, variance, and transformation components are all modelled parametrically, enabling a wide range of inferences. The general framework is illustrated by focusing on two problems: (1) analysis of the diagnostic accuracy of a covariate-dependent univariate test outcome requiring a Box-Cox transformation within each cluster to map the test outcomes to a common family of distributions; (2) development of an optimal composite diagnostic test using multivariate clustered outcome data. In the second problem, the composite test is estimated using discriminant function analysis and compared to the test derived from logistic regression analysis where the gold standard is a binary outcome. The proposed methodology is illustrated on prostate cancer biopsy data from a multi-centre clinical trial.

Bayes Theorem↗

PubMed1996

Physics and chemistry of film and processing.

An image containing the equivalent of almost 1 billion digital bits of diagnostic information can be recorded and displayed on a single sheet of film with use of a high-resolution screen-film radiographic system. The information storage capacity, versatility, and very low cost of screen-film radiographic systems are impressive. However, the inherent coupling of the recording and display functions does not allow optimization of these two functions independently, and this limitation has important implications for optimizing the radiographic image. The photographic process, including latent image formation and chemical development of that latent image, depends on many complex, time- and temperature-dependent phenomena that must be taken into consideration for optimizing the diagnostic image. Once the diagnostic image is processed and ready for viewing by transillumination, the complex response of the human eye requires careful attention to viewing conditions to optimize the information transfer from the film to the human observer.

Photography↗

PubMed2000

Progression criteria for cancer antigen 15.3 and carcinoembryonic antigen in metastatic breast cancer compared by computer simulation of marker data.

BACKGROUND: We investigated the utility of computer simulation models for performance comparisons of different tumor marker assessment criteria to define progression or nonprogression of metastatic breast cancer. METHODS: Clinically relevant values for progressive cancer antigen 15.3 and carcinoembryonic antigen concentrations were combined with representative values for background variations in a computer simulation model. Fifteen criteria for assessment of longitudinal tumor marker data were obtained from the literature and computerized. Altogether, 7200 different patients, each based on 50 measurements, were simulated. With a sampling interval of 4 weeks, the monitoring period for each event was approximately 3.8 years. RESULTS: Modulation of the background variation, the starting concentrations, and the cutoffs enabled identification of criteria that were robust against false-positive signals of progression. CONCLUSIONS: The computer simulation model is a fast, effective, and inexpensive approach for comparing the diagnostic potential of assessment criteria during clinically relevant conditions of steady-state and progressive disease. The model systems can be used to generate tumor marker assessment criteria for a variety of malignancies and to compare and optimize their diagnostic performance.

Breast Neoplasms↗

PubMed2006

Which radiological investigations should be performed to identify fractures in suspected child abuse?

AIMS: To determine which radiological investigations should be performed and which children should be investigated. MATERIALS AND METHODS: An all language literature search of original articles; from 1950-October 2005. Two reviewers independently reviewed each article. A third was carried out on disagreement. Each study was assessed using standardised data extraction, critical appraisal and evidence forms. RESULTS: Thirty-four studies were included. Fifteen addressed the question: which investigation has a higher yield, skeletal surveys (SS) or bone scintigraphy (BS)? Studies gave conflicting results. Overall neither investigation is as good as the two combined. BS predominately missed skull, metaphyseal and epiphyseal fractures, whereas SS commonly missed rib fractures. Two studies showed that a repeat SS 2 weeks after the initial study provided significant additional information about tentative findings, the number and age of fractures. A comparative study evaluated additional oblique views of ribs in 73 children and showed improved diagnostic sensitivity, specificity and accuracy. Four studies addressed the diagnostic yield for occult fractures with respect to age. This was significant for children under 2-years old. CONCLUSIONS: In children under 2-years old, where physical abuse is suspected, diagnostic imaging of the skeleton should be mandatory. SS or BS alone is inadequate to identify all fractures. It is recommended that all SS should include oblique views of the ribs. This review suggests that the following options would optimize the diagnostic yield. However, each needs to be evaluated prospectively: SS that includes oblique views, SS and BS, a SS with repeat SS or selected images 2 weeks later or a BS plus skull radiography and coned views of metaphyses and epiphyses.

Adolescent↗

PubMed2000

Publications on diagnostic test evaluation in family medicine journals: an optimal search strategy.

Search strategies for articles reporting on diagnostic test evaluations have been subjected to less research than those in the domain of clinical trials. We set out to develop an optimal search strategy for publications on diagnostic test evaluations in general, that could be added to keywords describing the specific diagnostic test at issue. Nine Family Medicine journals were searched from 1992 through 1995 for primary publications on diagnostic test evaluation by hand searching and a Medline search strategy published earlier. Additionally, new search strategies have been developed with stepwise logistic regression, using Mesh terms and free text words related to diagnosis and test evaluation as independent variables. Hand searching identified 75 primary publications on diagnostic test evaluation from a total of 2467 primary publications. The previously published search strategy had a sensitivity of 73%, a specificity of 94%, and a positive predictive value of 29%. The most accurate new search strategy had a sensitivity of 80.0% (60/75; 95% CI: 71.0-89.1), a specificity of 97.3% (2327/2392; 95% CI; 96.6-97.9%), a positive predictive value of 48% (95% CI: 40-56) and diagnostic odds ratio of 149. All four new strategies used the Mesh term "sensitivity and specificity" (exploded with the Mesh terms "predictive value" and "ROC")and cumulatively added the text words "specificity," "false negative," "accuracy," and "screening." The search strategy using the Mesh term "sensitivity and specificity" (exploded) and the text words "specificity," "false negative," and "accuracy" has both higher sensitivity and specificity than the previously published strategy. The increase in specificity in three strategies reduces the absolute number of false-positive articles that have to be screened by 50-75%, compared to the number of false positives in the earlier strategy.

Diagnostic Tests, Routine↗

PubMed1987

Comparison of Ca++ uptake and spontaneous Ca++ release from sarcoplasmic reticulum vesicles isolated from muscle of malignant hyperthermia diagnostic patients.

Inward Ca++ transport and spontaneous Ca++ release activities were compared among sarcoplasmic reticulum (SR) membrane fractions isolated from human skeletal muscle in patients undergoing malignant hyperthermia (MH) diagnostic contracture testing. Two different membrane fractions were isolated, a heavy (8-12,000 X g) and light (12-48,000 X g) fraction, from each diagnostic subject. The rates of inward Ca++ transport were faster in light SR compared to heavy SR, but no statistically significant difference was observed among MH diagnostic groups. Spontaneous Ca++ release occurred at optimum Ca++ preload in all SR fractions and this preload did not differ among MH diagnostic groups. Optimal Ca++ preload for rate of spontaneously released Ca++ was greater in light SR compared to heavy SR. Similarly, rate of Ca++ release was faster in light SR than in heavy SR, but no difference in rate of spontaneously released Ca++ was observed among MH diagnostic groups. Amount of Ca++ released did not differ among SR fractions and it did not differ among diagnostic groups. In contrast to previous studies showing a defect in Ca++-induced Ca++ release, the mechanisms related to spontaneous Ca++ release and to oxalate-facilitated inward Ca++ transport, as measured in this study, appear to be normal in SR from human MH skeletal muscle.

Calcium↗

PubMed1991

Assessment of antigen damage in immunohistochemistry. The vimentin internal control.

Monitoring of the quality of antigen preservation and the uniformity of tissue fixation in paraffin-embedded, formaldehyde-fixed tissues is facilitated by the routine use of an antibody to an epitope of vimentin that is partially susceptible to formaldehyde fixation. Other diagnostically useful molecules often show fixation- or processing-induced alterations that parallel those of the vimentin epitope. Thus, the use of vimentin as an internal control, or reporter molecule, and its extrapolation to other antigens allow for better interpretation of results, improved selection of fields optimal for diagnostic immunohistochemistry, and more rational application of compensatory procedures, such as protease digestion.

Animals↗

PubMed1998

[Diagnostic value of ERTL4: a screening test of language disorders in 4-year-old children].

BACKGROUND: Language disorders in children are frequent and may sometimes severely affect their development. ERTL4 (screening test for language disorders of children aged 4) is the first test for screening language disorders to be used by doctors. It has not yet been evaluated. AIM: The objective of this study is to assess and optimize the diagnostic value of the ERTL4 test and to evaluate its potential interest as a screening test. MATERIAL AND METHODS: A sample of 370 children was randomly constituted among children aged between 3 years 9 months and 4 years 6 months from schools in Nancy, France and surrounding areas. These children undertook both the ERTL4 test and a standardized examination of language and speech as a reference. RESULTS: Among the 325 children included in the analysis, 34.1% presented with disorders requiring speech and language therapy. ERTL4 sensitivity and specificity were 88.6% and 66.8%, respectively. Varying thresholds for disorder diagnoses and proposals for a modified test led to a sensitivity of 72.9% and a specificity of 91.0%. The proportion of well-classified subjects improved from 73.8% to 85.3% (P < 10(-3)). The positive predictive value was 78.7% and the negative predictive value was 88.1% (with the observed frequency in the sample). CONCLUSION: ERTL4 is a good test for doctors to screening of children's language disorders and their management.

Adolescent↗

PubMedDate not supplied

Objective determination of the optimal red blood cell count in diagnostic peritoneal lavage done for abdominal stab wounds.

The purpose of this study was to determine objectively the optimal value or positivity criterion for red blood cell counts in diagnostic peritoneal lavage in stab wounds to the anterior abdomen. Our study group consisted of 91 consecutive adults with abdominal stab wounds who underwent peritoneal lavage. We excluded those patients who met criteria for immediate laparotomy and those with negative stab wound exploration. We divided the patients into two groups based on outcome. Group 1 consisted of those who had undergone laparotomy and had findings that required surgical intervention. Group 2 patients had either undergone laparotomy but had no injury requiring surgical intervention or had no surgery and a benign hospital course and follow-up. Receiver operator characteristic analysis was done on the diagnostic peritoneal lavage RBC counts for both groups. The overlap between the groups was minimal, with 75% of patients in Group 1 having > 120,000 RBC/mm3 and 75% of patients in Group 2 having < 486 RBC/mm3 in the lavage effluent. Using the observed probability of 23.1% of patients with abdominal stab wounds requiring surgery, a RBC count of 50,000/mm3 discriminated best those patients who required surgery from those who did not.

Abdominal Injuries↗

PubMed1991

Is nuclear medicine cost-effective?

Clearly, there is currently no consensus on the cost-effectiveness of nuclear medicine--or in fact any other aspect of medicine. It is hoped that common sense prevails in clinical medicine today. An appropriate case history and physical examination may negate the need for any additional investigation. From the perspective of the capital cost of equipment and supply costs, ultrasound is clearly the most cost-effective diagnostic imaging modality. But while it is useful, it does not always provide definitive answers, and other modalities must be used to arrive at a diagnosis. In comparison, the capital cost of general radiology equipment and nuclear medicine equipment is relatively equal. Radiology has more operating costs per case than nuclear medicine and requires a lower staffing component per given volume of examinations. In any given diagnostic imaging procedure, the practitioner and imagist must maintain a dialogue to ascertain the appropriateness of the study and to use the available resources in the most effective manner. This is even more imperative when CT scanning and MRI are included in the equation. The development of an investigative protocol that makes the most efficient use of the various imaging modalities without compromising the quality of care makes sense for the patient, the physician and the insurance provider. It is unreasonable to expect the physician to be aware of the optimal protocol for the diagnostic workup of every patient. The guidance of the imaging department is required to maximize the efficient use of the available facilities. A critical and exhaustive appraisal of the medical literature may be required to determine the optimal diagnostic protocol.(ABSTRACT TRUNCATED AT 250 WORDS)

Capital Expenditures↗

PubMed1997

Bronchoscopic biopsy techniques in the diagnosis and staging of lung cancer.

In a review of the bronchoscopic biopsy techniques currently available for the diagnosis and staging of lung cancer, the author individually analyses the sampling instruments and procedures used in cancer of the central airways, peripheral lung lesions, and in the study of hilar and mediastinal lymph nodes. With regard to central bronchial lesions, data concerning diagnostic yield, the advantages and limits of forceps biopsy, brushing, washing and transbronchial needle aspiration are reported. With the integration of two or more of the sampling methods, a cytohistological diagnosis can be obtained in almost all cases. In the field of peripheral lung cancer, the diagnostic possibilities of the transbronchial approach are described. The experience of the Regional Hospital of Ancona, Italy on 1,027 patients affected by peripheral pulmonary nodules or masses is reported. The biopsy technique is based on the integration of transbronchial (using forceps biopsy and transbronchial needle aspiration) and percutaneous approaches, and on a team approach with the close co-operation of a pulmonologist, a radiologist and a cytopathologist, all simultaneously present in the diagnostic suite during the procedures. On the basis of the results obtained, the author suggests that, in peripheral pulmonary lesions, the transbronchial approach should generally be performed before the percutaneous needle aspirate, especially in patients who are candidates for surgery. The transbronchial approach has the advantages of allowing an examination of the tracheobronchial tree and staging of lymph nodes with a lower incidence of complications. In addition, the diagnostic yield of transbronchial needle aspiration in the study of hilar and mediastinal lymph nodes is analysed. This method, if positive, plays a major role in the staging of lung cancer and makes it possible to avoid unnecessary surgical procedures. Knowledge of the advantages and limits of different sampling instruments and procedures, and of their integration, is essential to optimize the diagnostic management of each patient with lung cancer. The goal is to maximize the diagnostic possibilities whilst minimizing risk and reducing costs.

Biopsy, Needle↗

PubMed1992

A comparison of two-dimensional echocardiography vs carotid duplex scanning in older patients with cerebral ischemia.

BACKGROUND: To determine the relative value of two-dimensional (2D) echocardiography vs carotid duplex scanning and to devise an optimal, cost-effective diagnostic approach for older patients with cerebral ischemia, 68 consecutive patients in sinus rhythm who suffered focal cerebral ischemia were studied. All patients underwent 2D echocardiography and carotid duplex scanning in addition to routine clinical evaluation. METHODS: Twenty-five of 68 patients had Q-wave myocardial infarction by electrocardiography; nine (36%) of these 25 had left ventricular mural thrombi demonstrated by 2D echocardiography. In contrast, none of 43 patients without Q-wave myocardial infarction had clinically unsuspected findings diagnosed by 2D echocardiography. Duplex scanning, however, identified significant, abnormal findings in the carotid artery ipsilateral to the involved cerebral hemisphere in 23 patients (34%). CONCLUSIONS: Thus, in older patients in sinus rhythm who suffer a cerebral ischemic event, carotid duplex scanning has a higher diagnostic yield than 2D echocardiography and appears to be a more cost-effective initial test. Our data suggest that in patients with carotid distribution cerebral ischemic events and no obvious cardiac source for emboli by history and physical examination, 2D echocardiography should be limited to those with evidence of Q-wave myocardial infarction by electrocardiography; such management should optimize diagnostic yield and cost effectiveness.

Aged↗

PubMed2002

Facing a prostate cancer diagnosis: who is at risk for increased distress?

BACKGROUND: The psychological adaptation to a cancer diagnosis is characterized by significant distress. Although distress levels in cancer patients have been reported to be the highest shortly after diagnosis and before treatment, few attempts have been made to study emotional adjustment during the diagnostic period of prostate cancer patients. This study's purpose was to determine whether differences in distress levels can be attributed to differences in diagnostic status, optimism, and/or coping strategies. METHODS: This study followed patients across 4 weeks, from prebiopsy to 2 weeks postdiagnosis, using these two time points as measurements. Data were collected between 1995 and 1998 at the Miami and Palo Alto VA Medical Center urology clinics. Biopsies were performed on 101 men (ages 46-87) to determine whether prostate cancer was present. These men completed prebiopsy and postdiagnosis questionnaires. RESULTS: Of optimism, coping, and cancer status, the only significant predictor of increased distress at postdiagnosis was dispositional avoidance at prebiopsy for both cancer and noncancer groups. CONCLUSIONS: Although these findings complement other studies linking avoidance with increased distress, the similarities between the cancer and noncancer groups underscore the need to consider both of these groups during the first few weeks of the prostate cancer diagnostic process.

Adaptation, Psychological↗

PubMed1987

Radiology of acute spinal trauma.

Radiologic diagnostic modalities utilized to evaluate acute spine trauma include plain films, tomography, computerized tomography (CT), myelography and CT-myelography, and magnetic resonance imaging. The initial evaluation is aimed at delineating the nature and extent of both boney and soft tissue injuries, with particular attention directed toward differentiating intrinsic cord damage from extrinsic spinal cord or nerve root compression that may respond to surgical intervention. The selection of the optimal radiologic diagnostic algorithm requires familiarization with the techniques and limitations of each diagnostic procedure.

Algorithms↗

PubMed1990

Optimized urinary microscopy for assessment of bacteriuria in primary care.

Microscopy of wet-stained urinary sediment as an indicator of bacteriuria was evaluated in 418 consecutive primary care visits in a small community. Delivery of morning urine was encouraged and contributed to bladder incubation times of 4 or more hours in 79% of the visits; the overall culture positivity was about 80%. Bacteria or leukocytes alone or together as minimal requirements were suboptimal microscopy criteria for bacteriuria, whereas a minimum of moderate amounts of bacteria or 5 leukocytes per high-power field (x400) as a cutoff point yielded the best diagnostic accuracy. Optimization of urinary sediment microscopy in this way resulted in a desirable high sensitivity (97%) and efficacy (86%) in acutely symptomatic patients, as well as reasonably high efficacy (79%) in other patients, independent of sex or bladder incubation time. The method's simplicity and speed recommend it for use in primary care, particularly in patients with acute symptoms of urinary tract infection.

Bacteriuria↗

PubMed2005

Clinical relevance of small-bowel findings detected by wireless capsule endoscopy.

OBJECTIVE: Capsule endoscopy is becoming known as a valid tool for identifying sources of obscure gastrointestinal (GI) bleeding. Fewer data are available about its clinical value for other indications. MATERIAL AND METHODS: Sixty patients (31 F, mean age 47 years, range 14-80 years) with no signs of overt GI bleeding were investigated by Given M2A video capsule for suspected small-bowel disease. The main clinical features were: iron deficient anemia (20), abdominal pain (12), chronic diarrhea (9), malabsorption and weight loss (7), Crohn's disease (CD) (5), and familial adenomatous polyposis (3). Three patients underwent wireless endoscopy for suspected GI neoplasm and one for portal thrombosis. RESULTS: Complete vision of the small bowel was achieved in 55 patients. No small-bowel lesions were identified in 17 patients, but 5 of them had gastric abnormalities. Small-bowel abnormality was found in 38 patients. Lesions compatible with CD were found in 14 patients, diffuse or patchy enteropathy in 7 and polyps in 6. Actively bleeding lesions were detected in 6 patients and potential bleeding sources in 5. Capsule endoscopy had an overall diagnostic yield of 62%. In particular, three small-bowel malignancies were detected and 9 patients received a better definition of their already-known pathology. However, further endoscopies were needed in 10 patients to obtain a diagnosis. One patient, diagnosed with ileal CD, underwent surgery, as the capsule remained trapped in a stricture. CONCLUSIONS: Wireless endoscopy effectively visualizes small-bowel abnormalities even though more accurate selection of the patients is needed in order to optimize its diagnostic efficacy.

Abdominal Pain↗

PubMed1978

Basic principles of ROC analysis.

The limitations of diagnostic "accuracy" as a measure of decision performance require introduction of the concepts of the "sensitivity" and "specificity" of a diagnostic test. These measures and the related indices, "true positive fraction" and "false positive fraction," are more meaningful than "accuracy," yet do not provide a unique description of diagnostic performance because they depend on the arbitrary selection of a decision threshold. The receiver operating characteristic (ROC) curve is shown to be a simple yet complete empirical description of this decision threshold effect, indicating all possible combinations of the relative frequencies of the various kinds of correct and incorrect decisions. Practical experimental techniques for measuring ROC curves are described, and the issues of case selection and curve-fitting are discussed briefly. Possible generalizations of conventional ROC analysis to account for decision performance in complex diagnostic tasks are indicated. ROC analysis is shown to be related in a direct and natural way to cost/benefit analysis of diagnostic decision making. The concepts of "average diagnostic cost" and "average net benefit" are developed and used to identify the optimal compromise among various kinds of diagnostic error. Finally, the way in which ROC analysis can be employed to optimize diagnostic strategies is suggested.

Cost-Benefit Analysis↗