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At least 811 records · Page 45Linked to original sources
PubMed2006

US or CT for Diagnosis of Appendicitis in Children and Adults? A Meta-Analysis.

PURPOSE: To perform a meta-analysis to evaluate the diagnostic performance of ultrasonography (US) and computed tomography (CT) for the diagnosis of appendicitis in pediatric and adult populations. MATERIALS AND METHODS: Medical literature (from 1986 to 2004) was searched for articles on studies that used US, CT, or both as diagnostic tests for appendicitis in children (26 studies, 9356 patients) or adults (31 studies, 4341 patients). Prospective and retrospective studies were included if they separately reported the rate of true-positive, true-negative, false-positive, and false-negative diagnoses of appendicitis from US and CT findings compared with the positive and negative rates of appendicitis at surgery or follow-up. Clinical variables, technical factors, and test performance were extracted. Three readers assessed the quality of studies. RESULTS: Pooled sensitivity and specificity for diagnosis of appendicitis in children were 88% (95% confidence interval [CI]: 86%, 90%) and 94% (95% CI: 92%, 95%), respectively, for US studies and 94% (95% CI: 92%, 97%) and 95% (95% CI: 94%, 97%), respectively, for CT studies. Pooled sensitivity and specificity for diagnosis in adults were 83% (95% CI: 78%, 87%) and 93% (95% CI: 90%, 96%), respectively, for US studies and 94% (95% CI: 92%, 95%) and 94% (95% CI: 94%, 96%), respectively, for CT studies. CONCLUSION: From the diagnostic performance perspective, CT had a significantly higher sensitivity than did US in studies of children and adults; from the safety perspective, however, one should consider the radiation associated with CT, especially in children.

Adult↗
PubMed1986

Effect of restraints on diagnostic approaches to abdominal pain and weight loss.

To examine the effects of restraint on the diagnostic process, 25 physicians were urged to be as economical as possible when requesting diagnostic tests for case report simulations of nine patients who had previously been hospitalized with abdominal pain and weight loss. The results of the tests correctly changed the physicians' initial diagnoses, increased their diagnostic confidence, and led to appropriate management decisions. When restrained, individual physicians needed only 3.0 (1.7 to 4.1) diagnostic procedures per patient to reach management decisions, whereas 6.1 (3.0 to 11) diagnostic procedures had actually been performed. Diagnostic approaches were so diverse, however, that the number of procedures collectively requested by randomly assembled "teams" consisting of four to five "economical" physicians equaled the number of procedures actually performed. Moreover, 20 percent of the procedures requested by "economical" physicians were invasive compared with only 7 percent of those actually performed. These findings suggest that, without uniform diagnostic approaches, "team" management may increase testing despite restraint by individual physicians. Moreover, quests for economy may increase invasive diagnostic testing.

Abdomen↗
PubMed1988

The dot plot. A starting point for evaluating test performance.

We suggest that evaluations of diagnostic tests start with dot plots that depict multiple test results over multiple clinical states. From this starting point we can calculate posttest probabilities for multiple clinical states at multiple test results. Also, we can project one subset of clinical states as "disease positive" and a second subset as "disease negative" to provide standard analyses such as likelihood ratios, relative operating characteristic curves, posttest/pretest probability plots, sensitivity, specificity, and predictive value. Finally, this starting point provides an excellent basis for comparing multiple studies of diagnostic performance. The advantages of dot plots are illustrated with data on serum ferritin levels over multiple clinical states.

Ferritins↗
PubMed1996

Safe application of diagnostic laparoscopy during biventricular assistance.

We performed diagnostic laparoscopy in a patient who was critically unstable while on an ABIOMED BVS 5000 biventricular assist system. A relatively unique feature of the ABIOMED is the venous return being dependent only on gravity and the drawing force of venous return being the height of the inflow cannula compared with the level of the ABIOMED blood pump assembly; this did not preclude the use of pneumoperitoneum necessary for laparoscopy. The safe application of diagnostic laparoscopy in patients on a ventricular assist device is of importance in an era of increasing use of these devices and the increased potential for intraabdominal complications in this population.

Abdomen, Acute↗
PubMed1978

Cost of carrying out clinical diagnostic tests.

The total cost of performing diagnostic tests in a hospital laboratory during one year was assessed. The largest single item of expenditure was the cost of the salaries of the technical staff, while the cost of reagents (including radiopharmaceuticals) was relatively small. The total costs of carrying out diagnostic tests are much higher than is often recognised by those who request them. The use of relatively expensive, commercially available assay kits saves time and gives good value for money. It may be worth taking this into account when planning hospital budgets.

Blood Specimen Collection↗
PubMed2007

Evaluation of an intelligent tutoring system in pathology: effects of external representation on performance gains, metacognition, and acceptance.

OBJECTIVE: Determine effects of computer-based tutoring on diagnostic performance gains, meta-cognition, and acceptance using two different problem representations. Describe impact of tutoring on spectrum of diagnostic skills required for task performance. Identify key features of student-tutor interaction contributing to learning gains. DESIGN: Prospective, between-subjects study, controlled for participant level of training. Resident physicians in two academic pathology programs spent four hours using one of two interfaces which differed mainly in external problem representation. The case-focused representation provided an open-learning environment in which students were free to explore evidence-hypothesis relationships within a case, but could not visualize the entire diagnostic space. The knowledge-focused representation provided an interactive representation of the entire diagnostic space, which more tightly constrained student actions. MEASUREMENTS: Metrics included results of pretest, post-test and retention-test for multiple choice and case diagnosis tests, ratios of performance to student reported certainty, results of participant survey, learning curves, and interaction behaviors during tutoring. RESULTS: Students had highly significant learning gains after one tutoring session. Learning was retained at one week. There were no differences between the two interfaces in learning gains on post-test or retention test. Only students in the knowledge-focused interface exhibited significant metacognitive gains from pretest to post-test and pretest to retention test. Students rated the knowledge-focused interface significantly higher than the case-focused interface. CONCLUSIONS: Cognitive tutoring is associated with improved diagnostic performance in a complex medical domain. The effect is retained at one-week post-training. Knowledge-focused external problem representation shows an advantage over case-focused representation for metacognitive effects and user acceptance.

Attitude to Computers↗
PubMed1996

Analysis of gland volume effect on the performance of PSA density in early detection of non-palpable, isoechoic prostate cancer.

OBJECTIVE: To reassess PSA density (PSAD) in the detection of non-palpable, isoechoic prostate cancer and to analyze the effect of potentially inaccurate non-planimetric transrectal ultrasound volume estimates on the diagnostic performance of this diagnostic tool. METHODS: We prospectively evaluated 343 consecutive men with non-suspicious digital rectal examination and transrectal ultrasound findings and with serum PSA in the intermediate range (4.1-10 ng/mL). All men underwent systematic sextant biopsies of the peripheral zone. We performed a two-fold analysis of PSAD performance first using measured gland volume and then using modified gland volumes ranging from a 25% underestimation to a 25% overestimation, in 5% stepwise increments. RESULTS: With a 0.15 PSAD cut-off, we would have missed 14, 34 and 48% of cancers, if we had respectively used a volume underestimate of 25%, the measured volume and a volume overestimate of 25%. CONCLUSIONS: Potential gland volume under- or overestimation may substantially affect the diagnostic performance of PSAD. Although PSAD may represent a useful adjunct in the early detection of prostate cancer, it may compromise cancer detection in a substantial proportion of cases, if used as the only indicator for biopsy.

Journal Article↗
PubMed1993

Cost-effectiveness in nuclear medicine.

There are many pressures on nuclear medicine physicians to keep costs down and to produce the most efficacious results for the money spent. A procedure is cost-effective if its benefits (correct diagnosis, effective treatment, etc.) are worth the additional costs (money, radiation dose, etc.). The benefits of diagnostic procedures are measured by test performance (diagnostic efficacy [efficacy-D]), which in turn depends on a specific task: detection, classification, localization, or quantitation. For the detection task, measures of test performance include sensitivity, specificity, predictive value, accuracy, diagnostic utility, posttest versus pretest disease probability, area under a receiver operating characteristic (ROC) curve, and others. Standard measures of test performance in the classification, localization, and quantitation tasks have not yet been developed. Efficacy-M (management efficacy) is a measure of the extent to which a procedure influences patient management appropriately. Efficacy-O (outcome efficacy) is a measure of the success of therapeutic procedures. Some publications illustrating these points are presented. Costs associated with nuclear medicine procedures include money, time, discomfort, possible drug reactions, radiation dose, and the hypothetical risk of radiation-associated cancer. The public's perception of these latter risks, or costs, is much higher than our knowledge would justify. Decision trees are useful for laying out all possible strategies, outcomes, costs, and benefits, and estimating the cost-effectiveness of each strategy. Some articles estimating cost-effectiveness in nuclear medicine are reviewed, although few articles in the literature make any detailed use of decision analysis. Much work remains to be done in forming a coherent, consistent procedure for assessing cost-effectiveness in nuclear medicine.

Cost-Benefit Analysis↗
PubMed1990

[Ultrasonic diagnosis of the upper abdomen performed in general practice].

This paper considers the use of ultrasound diagnostics performed by a general practitioner on patients with pain in the upper abdominal region, with particular attention to the liver, gallbladder and aorta. 189 patients were examined, of whom 48 were found to have one or more diseases. 55 specific diagnoses were made. 23 patients had gallstones, and five had aortic aneurysm. Malignant diseases were suspected in five patients. The negative results were evaluated by means of a questionnaire after completion of the period of registration. This questionnaire did not expose any undiagnosed disease in the examined organs. We conclude that ultrasound diagnostics may be performed on this group of patients by interested general practitioners with special training.

Abdomen↗
PubMed1997

"Surgical" ultrasound in suspected acute appendicitis.

BACKGROUND: Ultrasonography (US) by acknowledged experts enhances the diagnostic performance and reduces the rate of negative laparotomies in patients with suspected acute appendicitis (AA). METHODS: The diagnostic accuracy and clinical impact of routine US performed by surgical residents was prospectively studied in 504 unselected patients admitted for AA. Clinical and US findings were correlated with laparotomy findings and pathological outcome in 135 patients (113 cases with proven AA, prevalence 22.4%) and clinical as well as follow-up data were compared in the remainder. RESULTS: The overall accuracy, sensitivity, and specificity of the clinical diagnosis of AA were 84.9%, 51.3%, and 94.6% and those of US were 93. 6%, 83.1%, and 96.6%. Joint evaluation of the results from clinical evaluation and US further improved diagnostic performance (accuracy 93.4%, sensitivity 84.1%, specificity 96.2) and significantly reduced the rate of diagnostic errors to 3.4% (p < 0.001) and unnecessary laparotomies to 9.6% (p < 0.01) in patients with suspected AA. CONCLUSIONS: Ultrasonographic evaluation of the patient with suspected AA is considered to be of value in surgical practice.

Acute Disease↗
PubMed2006

Diagnosis of lumbar spinal stenosis: a systematic review of the accuracy of diagnostic tests.

STUDY DESIGN: Systematic review of diagnostic studies. OBJECTIVE: To investigate the diagnostic performance of tests used to detect lumbar spinal stenosis. SUMMARY OF BACKGROUND DATA: Little is known about the diagnostic accuracy of tests in detecting lumbar spinal stenosis. A systematic review will provide more insight in this topic. METHODS: We performed a literature search in Medline (PubMed) and Embase for original diagnostic studies on lumbar spinal stenosis, in which one or more different tests were evaluated with a reference standard, and diagnostic values were reported or could be calculated. Two reviewers independently checked all abstracts and full text articles for inclusion criteria. Included articles were assessed for their quality using the Quadas tool. Study features and diagnostic values were extracted from the included studies. RESULTS: Of the 24 articles included in this review, 15 concerned imaging tests, 7 evaluated "clinical tests," and 2 reported on other diagnostic tests. The overall quality was poor; only 5 studies scored positive on more than 50% of the quality items. Estimates of the diagnostic value of the tests differed considerably. The imaging studies showed no superior accuracy for myelography compared with CT or MRI. Overall, there is considerable variation in the clinical tests; some studies show high sensitivity, whereas others show high specificity. CONCLUSIONS: Because of heterogeneity and overall poor quality, no firm conclusions about the diagnostic performance of the different tests can be drawn. Better-designed studies exploring the accuracy of diagnostic tests are needed to improve the diagnostic policy.

Diagnostic Tests, Routine↗
PubMed2005

The galenic venous system: surgical anatomy and its angiographic and magnetic resonance venographic correlations.

OBJECTIVE: This study aims at evaluating the adequacy of digital subtraction angiography and magnetic resonance venography in imaging of the galenic venous system for surgical planning of approaches to the pineal region. Anatomical dissections were carried out in 10 cadavers of several age groups and these were compared to imaging findings in 10 living subjects. METHODS: The presence or absence of 10 predetermined veins or vein groupings belonging to the galenic venous system were prospectively analyzed in 10 cadaver dissections and imaging findings of 10 age matched human subjects. The studied vessels were the vein of galen, the internal cerebral veins, both basal vein of Rosenthals, internal occipital vein, occipitotemporal veins, precentral cerebellar veins, tectal veins, pineal veins, superior vermian veins (including superior cerebellar veins (SCVs)) and posterior pericallosal veins. Each of the subjects had both digital subtraction angiography and magnetic resonance venography studies performed. Diagnostic digital subtraction angiography was performed using the transfemoral route and the venous phase was used for the study. Magnetic resonance venography was performed in 1.5 T MRI equipment using the 2D-TOF sequence. All studies were reported to be normal. RESULTS: There was wide variation in the anatomy of the galenic venous system. There were interpersonal, intrapersonal and age related variations. Both the digital subtraction angiography and the magnetic resonance venography were efficient at demonstrating large veins. However, smaller veins were less readily demonstrated in either study. The general sensitivities of the digital subtraction angiography and the magnetic resonance venography for the galenic venous system were 45.5% and 32.5%, respectively. Surgically important veins were missed in most studies. CONCLUSIONS: Anatomically, the galenic venous system is highly variable. This variability is caused by interpersonal, intrapersonal and age related differences and causes each individual galenic venous system to be unique. Therefore, modern neurosurgical procedures require anatomical information on individual differences. Current radiological methods of digital subtraction angiography and magnetic resonance venography fail short of providing the necessary information. New and more sophisticated MRI technology may fulfill this need.

Adult↗