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Results for “diagnostic optimization”

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PubMedDate not supplied

Comparing and optimizing diagnostic tests: an information-theoretical approach.

An ideal method for assessing performance of non-binary diagnostic tests would specify each test's optimal operating point and would tell a diagnostician which of many tests was the best one to use in a particular clinical situation. This article shows how information theory and receiver operating characteristic (ROC) analysis can be combined to evaluate and compare diagnostic tests at their optimum cutoffs once disease prevalence and test properties are specified. Though it is not appropriate for all clinical situations, the method can be used for most diagnostic tests whenever information is desired for its own sake or when reducing uncertainty is the goal of testing. The method also is appropriate in those situations where benefits and costs cannot be specified precisely enough to permit test optimization based on a balancing of anticipated goods and evils.

Diagnostic Tests, Routine↗
PubMed1992

Balancing risks and benefits: another approach to optimizing diagnostic tests.

In our last two articles, we showed that one can quantify the reduction in uncertainty that results from diagnostic testing, an insight that allowed us to describe a method for optimizing the performance of a test by choosing a cutoff that maximizes its information yield. Although minimizing uncertainty is an important feature of diagnostic testing, there are many situations in which diagnostic tests are most appropriately used to balance risks and benefits associated with the various possible courses of action available to a clinician. This article shows how tests can be used to maximize the "expected utility" associated with a clinical decision.

Humans↗
PubMed1985

Diagnostic tests in breast cancer. Clinical strategies based on diagnostic probabilities.

Optimal diagnostic strategies used in screening for breast cancer and evaluating breast masses depend on the likelihood of malignancy, findings at physical examination, and the accuracy of tests and procedures. Results from published series, in conjunction with calculations of the probability of malignancy based on test results, indicate that only mammography is needed for screening. A clinical sequence for evaluating palpable breast masses should include a combination of mammography, ultrasound examination, and needle aspiration. In patients with negative findings, the probability of cancer will be sufficiently low to obviate the need for immediate surgical biopsy. However, if there are positive findings, or the initial clinical likelihood of malignancy is high, excision of the mass is indicated.

Adult↗
PubMed1989

Evaluation and optimization of diagnostic tests using receiver operating characteristic analysis and information theory.

We describe a mathematical technique and an associated computer program for comparing, evaluating and optimizing diagnostic tests. The technique combines receiver operating characteristic (ROC) analysis with information theory and cost-benefit analysis to accomplish this. The program is menu driven and highly interactive; it generates 13 possible user-determined ASCII disk files which can be easily converted to graphs. These graphs allow the user to make detailed comparisons among various diagnostic tests for all values of disorder prevalence, and also provide guidelines for cut-off selection in order to optimize tests. These techniques are applied to three published studies of the enzyme screening assay for diagnosis of infection with the HIV virus. We show how graphs produced by this program can be used to compare and optimize these diagnostic tests. The program is written for an IBM-compatible microcomputer running on a DOS operating system.

Clinical Laboratory Techniques↗
PubMed1989

[Optimalization of diagnostic choices].

The sensitivity and specificity of diagnostic tests and the Gold Standard are introduced. An optimization method for diagnosis, based on the utility function is presented. It is emphasized that the conclusions reached in practice depend on the numerical values subjectively assigned to some parameters. A careful application of such methods is recommended.

Diagnosis↗
PubMed1987

Chronic cholecystitis. An analysis of diagnostic strategies.

To define the optimal diagnostic approach for suspected chronic cholecystitis comprehensive management strategies were developed. Using a computer model, the frequency of appropriate surgery, inappropriate surgery, complications, death, and medical costs were compared in populations of patients with various disease prevalences. The optimal strategy began with ultrasonography, followed by an oral cholecystogram when the ultrasonogram was inconclusive. Oral cholecystogram also was employed when additional diagnostic studies failed to provide another explanation for the patient's symptoms. Compared with strategies using only ultrasonography or oral cholecystography, the combination strategy lowered the frequency of inappropriate surgery from 7.1 to 4.4% and direct medical costs from $1,877 to $1,766 per patient in a population with a 20% prevalence of chronic cholecystitis. The differences persisted at higher prevalences of cholecystitis and when sensitivities and specificities of the tests were varied over ranges reported in the literature. Diagnostic accuracy and direct medical costs could be improved by a more frequent interpretation of subtle abnormal ultrasonographic findings as inconclusive and by a more liberal use of oral cholecystography. This analysis demonstrates that a strategy combining ultrasonography and oral cholecystography is superior to the use of either test alone and is cost-efficient.

Cholecystitis↗
PubMed1985

Differential diagnosis and the competing-hypotheses heuristic. A practical approach to judgment under uncertainty and Bayesian probability.

Evaluating the same diagnostic information across the plausible competing diagnoses is a practical strategy (ie, heuristic) to guide decision making in the face of uncertainty. The prevalence of use of this competing-hypotheses heuristic by 89 first-year house officers was examined in three simulated patient cases. Results indicated that only a minority (24%) of the house officers selected optimal diagnostic information consistent with this Bayesian heuristic across all three cases. Almost all (97%) of the house officers selecting optimal diagnostic information were able to identify the most probable diagnosis specified by Bayes' theorem, while only a chance number (53%) of house officers selecting nonoptimal information were able to identify the most probable diagnosis. The competing-hypotheses heuristic is discussed within the context of diagnostic problem-solving models derived from the literature on medical decision making and clinicopathological conference case records. It is suggested that the heuristic, which does not necessitate any mathematical calculations, may be useful as a complement to clinical judgment.

Bayes Theorem↗
PubMed1988

Mammary Paget's disease and intraductal carcinoma. Histologic, histochemical, and immunocytochemical comparison.

This study of mammary Paget's disease was carried out with the objects of clarifying its histogenesis and of determining optimal diagnostic measures. Ten consecutive cases of mammary Paget's disease with their underlying ductal carcinomas were compared. Histologic, histochemical, and immunocytochemical examination mainly supported the hypothesis that mammary Paget's disease is an extension of mammary ductal carcinoma into the overlying nipple epithelium. However, two of our ductal carcinomas stained strongly with S-100 protein, while Paget's disease was uniformly negative with this antibody. The significance of this finding is not known. Optimal diagnostic accuracy is obtained by using a combination of routinely stained sections along with a panel of immunocytochemical stains. Nipple wedge biopsy may demonstrate both intraduct carcinoma and Paget's disease, and is thus a superior biopsy technique.

Biopsy↗
PubMed1986

Computer-aided diagnostic strategy selection.

Determination of the optimal diagnostic work-up strategy for the patient is becoming a major concern for the practicing physician. Overlap of the indications for various diagnostic procedures, differences in their invasiveness or risk, and high costs have made physicians aware of the need to consider the choice of procedure carefully, as well as its relation to management actions available. In this article, the author discusses research approaches that aim toward development of formal decision analytic methods to allow the physician to determine optimal strategy; clinical algorithms or rules as guides to physician decisions; improved measures for characterizing the performance of diagnostic tests; educational tools for increasing the familiarity of physicians with the concepts underlying these measures and analytic procedures; and computer-based aids for facilitating the employment of these resources in actual clinical practice.

Artificial Intelligence↗
PubMed1989

[The gold standard and optimalization of diagnostic choice: the pulmonary nodule and transthoracic pulmonary puncture-biopsy].

In this review of the literature, it is emphasized that the published results about the transthoracic pulmonary needle biopsy (TPNB) cannot be readily evaluated due to the inconsistency of the reference tests, the methods and the investigated subjects. Gold-standards for evaluation of lung tumors have been described and are recalled. The limits of the TPNB are pointed out in the diagnosis of solitary pulmonary nodules and benign lesions. In a bayesian approach, it is shown that the TPNB is only useful in confirming an a-priori diagnosis of cancer.

Bayes Theorem↗
PubMed1989

[Diagnostic value of serological tumor marker tests in patients with ovarian cancer].

The usefulness of tumor markers in serodiagnosis of cancer designed to detect ovarian cancer at an early stage was evaluated from the point of view of their diagnostic value. Namely, eight tumor markers, CA125, SLX, CA72-4, TPA, Fr, CEA, CA19-9, and SCC, were determined and studied to find the combination that would yield the optimal diagnostic value. For this purpose, the diagnostic value was calculated from sensitivity x specificity. As a single tumor marker CA125 proved optimal with a diagnostic value of 0.50. The higher value, 0.53, was obtained as the diagnostic value from the combination of two tumor markers, CA125 and CA72-4. When three tumor markers were combined, CA125, CA72-4 and SLX gave an optimal diagnostic value of 0.65. In the combination of four tumor markers, CA125, CA72-4, SLX and CA19-9 gave a diagnostic value of 0.63. In the five marker combination CA125, CA72-4, SLX, CA19-9 and TPA worked well and had a diagnostic value of 0.59. When the markers were increased to six types, CA125, CA72-4, SLX, CA19-9, TPA and Fr provided a combination with 0.53 as the diagnostic value. In the seven marker combination CA125, CA72-4, SLX, CA19-9, TPA, Fr and CEA gave a diagnostic value of 0.51. The efficiency declined to 0.51 when eight tumor markers were combined. When cost performance in the measurement of tumor markers for early detection of ovarian cancer is taken into account, a dilemma arises in that the increase in the number of tumor markers used is accompanied by higher sensitivity and lower specificity.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Neoplasm↗
PubMedDate not supplied

Alternate AP knee method assures open joint space.

An alternate method of imaging the knee in the AP projection assures diagnostic joint spaces to provide optimal diagnostic information. The degree of angulation is varied from 5 degrees cephalic to 5 degrees caudal and is determined by measuring the patient's anterior superior iliac spine to table-top distance.

Arthrography↗