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Constantine Gatsonis

Publications and source records attributed to Constantine Gatsonis.

12 recordsLinked to original sources
PubMed2006

Meta-analysis of diagnostic and screening test accuracy evaluations: methodologic primer.

OBJECTIVE: Interest in evidence-based diagnosis is growing rapidly as diagnostic and screening techniques proliferate. In this article we provide an overview of systematic reviews of diagnostic performance and discuss in detail statistical methods for the most common variant of the problem: meta-analysis of studies in which a pair of estimates of sensitivity and specificity is reported. The need to account for possible variations in threshold for test positivity across studies led to the formulation of the Summary ROC (SROC) curve method. We discuss graphical and model-based ways to estimate, summarize, and compare SROC curves, and we present an example from a meta-analysis of data on techniques for staging cervical cancer. We also present a brief survey of the methodologic literature for addressing heterogeneity, correlated data, multiple thresholds per study, and systematic reviews of ROC studies. We conclude with a discussion of the significant methodologic challenges that continue to face investigators in this area of diagnostic medicine research. CONCLUSION: Systematic reviews of diagnostic performance are a rigorous approach to examining and synthesizing evidence in the evaluation of diagnostic and screening tests. The information from such reviews is needed by clinicians, health policy makers, researchers in diagnostic medicine, developers of diagnostic techniques, and the general public. However, despite progress in study quality and reporting and in methodologic development, major challenges confront investigators undertaking these reviews.

Diagnostic Techniques and Procedures↗
PubMed2005

Role of imaging in pretreatment evaluation of early invasive cervical cancer: results of the intergroup study American College of Radiology Imaging Network 6651-Gynecologic Oncology Group 183.

PURPOSE: To compare magnetic resonance imaging (MRI) and computed tomography (CT) with each other and to International Federation of Gynecology and Obstetrics (FIGO) clinical staging in the pretreatment evaluation of early invasive cervical cancer, using surgicopathologic findings as the reference standard. PATIENTS AND METHODS: This prospective multicenter clinical study was conducted by the American College of Radiology Imaging Network and the Gynecologic Oncology Group from March 2000 to November 2002; 25 United States health centers enrolled 208 consecutive patients with biopsy-confirmed cervical cancer of FIGO stage > or = IB who were scheduled for surgery based on clinical assessment. Patients underwent FIGO clinical staging, helical CT, and MRI. Surgicopathologic findings constituted the reference standard for statistical analysis. RESULTS: Complete data were available for 172 patients; surgicopathologic findings were consistent with FIGO stages IA to IIA in 76% and stage > or = IIB in 21%. For the detection of advanced stage (> or = IIB), sensitivity was poor for FIGO clinical staging (29%), CT (42%), and MRI (53%); specificity was 99% for FIGO clinical staging, 82% for CT, and 74% for MRI; and negative predictive value was 84% for FIGO clinical staging, 84% for CT, and 85% for MRI. MRI (area under the receiver operating characteristic curve [AUC], 0.88) was significantly better than CT (AUC, 0.73) for detecting cervical tumors (P = .014). For 85% of patients, FIGO clinical staging forms were submitted after MRI and/or CT was performed. CONCLUSION: CT and MRI performed similarly; both had lower staging accuracy than in prior single-institution studies. Accuracy of FIGO clinical staging was higher than previously reported. The temporal data suggest that FIGO clinical staging was influenced by CT and MRI findings.

Adenocarcinoma↗
PubMed2005

Utilization of diagnostic studies in the pretreatment evaluation of invasive cervical cancer in the United States: results of intergroup protocol ACRIN 6651/GOG 183.

PURPOSE: To review the current utilization of diagnostic tests prescribed by the International Federation of Gynecology and Obstetrics (FIGO) clinical staging guidelines in the pretreatment work-up of invasive cervical cancer, and to compare the data with those of previous patterns of care studies. PATIENTS AND METHODS: This interdisciplinary American College of Radiology Imaging Network/Gynecologic Oncology Group prospective clinical trial was conducted between March 1, 2000, and November 11, 2002. Twenty-five participating institutions, all from the United States, enrolled a total of 208 patients. Only patients scheduled for surgery with biopsy-confirmed cervical cancer of clinical FIGO stage IB or higher were eligible. The patterns of care data analysis was based on 197 patients who met all inclusion criteria. The conventional FIGO-recommended tests used for pre-enrollment FIGO clinical stage classification were at the discretion of the treating physician; overall frequency of use was tabulated for each test. RESULTS: Use of cystoscopy (8.1%) and sigmoidoscopy or proctoscopy (8.6%) was significantly lower than in 1988 to 1989 (P < .0001 in each instance). Intravenous urography was used in only 1% of patients as compared with 42% in 1988 to 1989 and 91% in 1983. No patient included in the data analysis had barium enema or lymphangiography. Only 26.9% of patients had examination under anesthesia for FIGO clinical staging. CONCLUSION: There is a large discrepancy between the diagnostic tests recommended by FIGO and the actual tests used for cervical cancer staging, suggesting a need to reassess the relevance of the FIGO guidelines to current clinical practice in the United States.

Adult↗
PubMed2005

Added cancer yield of MRI in screening the contralateral breast of women recently diagnosed with breast cancer: results from the International Breast Magnetic Resonance Consortium (IBMC) trial.

OBJECTIVE: To estimate the added cancer yield of magnetic resonance imaging (MRI) over mammography in the contralateral breast of patients with a recent diagnosis of breast cancer. METHODS: We conducted a prospective, international study of mammography and MRI in women with a recent diagnosis of unilateral breast cancer. Each subject received a mammogram, clinical breast exam (CBE), and MRI of the unaffected breast within a 90 day time period. Definitive diagnosis of suspicious findings was determined through biopsy and central pathology review. RESULTS: Of the 103 eligible women included in study analyses, MRI detected 4 cancers in the contralateral breast while mammography detected none. MRI resulted in 12% (95% CI, 6%-20%) of women recommended for biopsy and 10% of women undergoing additional biopsy. The added cancer yield of MRI was 4% (95% CI, 1%-10%) and the positive predictive value of an abnormal MRI was 33% (95% CI, 10%-65%). Forty percent (4/10) of the biopsies performed based on the MRI recommendation were positive for malignancy. CONCLUSION: In women with a recent breast cancer diagnosis, approximately 4% will have an otherwise occult invasive breast cancer detected in the opposite breast by MRI alone.

Biopsy↗
PubMed2005

Diagnostic performance of digital versus film mammography for breast-cancer screening.

BACKGROUND: Film mammography has limited sensitivity for the detection of breast cancer in women with radiographically dense breasts. We assessed whether the use of digital mammography would avoid some of these limitations. METHODS: A total of 49,528 asymptomatic women presenting for screening mammography at 33 sites in the United States and Canada underwent both digital and film mammography. All relevant information was available for 42,760 of these women (86.3 percent). Mammograms were interpreted independently by two radiologists. Breast-cancer status was ascertained on the basis of a breast biopsy done within 15 months after study entry or a follow-up mammogram obtained at least 10 months after study entry. Receiver-operating-characteristic (ROC) analysis was used to evaluate the results. RESULTS: In the entire population, the diagnostic accuracy of digital and film mammography was similar (difference between methods in the area under the ROC curve, 0.03; 95 percent confidence interval, -0.02 to 0.08; P=0.18). However, the accuracy of digital mammography was significantly higher than that of film mammography among women under the age of 50 years (difference in the area under the curve, 0.15; 95 percent confidence interval, 0.05 to 0.25; P=0.002), women with heterogeneously dense or extremely dense breasts on mammography (difference, 0.11; 95 percent confidence interval, 0.04 to 0.18; P=0.003), and premenopausal or perimenopausal women (difference, 0.15; 95 percent confidence interval, 0.05 to 0.24; P=0.002). CONCLUSIONS: The overall diagnostic accuracy of digital and film mammography as a means of screening for breast cancer is similar, but digital mammography is more accurate in women under the age of 50 years, women with radiographically dense breasts, and premenopausal or perimenopausal women. (ClinicalTrials.gov number, NCT00008346.)

Adult↗
PubMed2005

Screening women at high risk for breast cancer with mammography and magnetic resonance imaging.

BACKGROUND: The authors compared the performance of screening mammography versus magnetic resonance imaging (MRI) in women at genetically high risk for breast cancer. METHODS: The authors conducted an international prospective study of screening mammography and MRI in asymptomatic, genetically high-risk women age >/= 25 years. Women with a history of breast cancer were eligible for a contralateral screening if they had been diagnosed within 5 years or a bilateral screening if they had been diagnosed > 5 years previously. All examinations (MRI, mammography, and clinical breast examination [CBE]) were performed within 90 days of each other. RESULTS: In total, 390 eligible women were enrolled by 13 sites, and 367 women completed all study examinations. Imaging evaluations recommended 38 biopsies, and 27 biopsies were performed, resulting in 4 cancers diagnosed for an overall 1.1% cancer yield (95% confidence interval [95%CI], 0.3-2.8%). MRI detected all four cancers, whereas mammography detected one cancer. The diagnostic yield of mammography was 0.3% (95%CI, 0.01-1.5%). The yield of cancer by MRI alone was 0.8% (95%CI, - 0.3-2.0%). The biopsy recommendation rates for MRI and mammography were 8.5% (95%CI, 5.8-11.8%) and 2.2% (95%CI, 0.1-4.3%). CONCLUSIONS: Screening MRI in high-risk women was capable of detecting mammographically and clinically occult breast cancer. Screening MRI resulted in 22 of 367 of women (6%) who had negative mammogram and negative CBE examinations undergoing biopsy, resulting in 3 additional cancers detected. MRI also resulted in 19 (5%) false-positive outcomes, which resulted in benign biopsies.

Adult↗
PubMed2005

Error reporting and disclosure systems: views from hospital leaders.

CONTEXT: The Institute of Medicine has recommended establishing mandatory error reporting systems for hospitals and other health settings. OBJECTIVE: To examine the opinions and experiences of hospital leaders with state reporting systems. DESIGN AND SETTING: Survey of chief executive and chief operating officers (CEOs/COOs) from randomly selected hospitals in 2 states with mandatory reporting and public disclosure, 2 states with mandatory reporting without public disclosure, and 2 states without mandatory systems in 2002-2003. MAIN OUTCOME MEASURES: Perceptions of the effects of mandatory systems on error reporting, likelihood of lawsuits, and overall patient safety; attitudes regarding release of incident reports to the public; and likelihood of reporting incidents to the state or to the affected patient based on hypothetical clinical vignettes that varied the type and severity of patient injury. RESULTS: Responses were received from 203 of 320 hospitals (response rate = 63%). Most CEOs/COOs thought that a mandatory, nonconfidential system would discourage reporting of patient safety incidents to their hospital's own internal reporting system (69%) and encourage lawsuits (79%) while having no effect or a negative effect on patient safety (73%). More than 80% felt that the names of both the hospital and the involved professionals should be kept confidential, although respondents from states with mandatory public disclosure systems were more willing than respondents from the other states to release the hospital name (22% vs 4%-6%, P = .005). Based on the vignettes, more than 90% of hospital leaders said their hospital would report incidents involving serious injury to the state, but far fewer would report moderate or minor injuries, even when the incident was of sufficient consequence that they would tell the affected patient or family. CONCLUSIONS: Most hospital leaders expressed substantial concerns about the impact of mandatory, nonconfidential reporting systems on hospital internal reporting, lawsuits, and overall patient safety. While hospital leaders generally favor disclosure of patient safety incidents to involved patients, fewer would disclose incidents involving moderate or minor injury to state reporting systems.

Attitude of Health Personnel↗
PubMed2003

Adherence to practice guidelines: the role of specialty society guidelines.

BACKGROUND: Physician adherence to guidelines is often poor, but the reasons have not been completely studied. We investigated whether physician adherence to guidelines for percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) varied by source, development methods, or the extent of their evidence-base. METHODS AND RESULTS: We assessed adherence to guidelines developed by the American College of Cardiology/American Heart Association (ACC/AHA) for PTCA (1988 and 1993) and for CABG (1990) and guidelines developed by RAND for PTCA and CABG in 1990. We randomly sampled patients on Medicare who were undergoing coronary angiography in 5 states in 1991 and 1992, extracting clinical and laboratory data from medical records and using computer programs to classify the appropriateness of each procedure. A total of 543 PTCA and 676 CABG procedures were studied. By use of the 1988 ACC/AHA guidelines, 30% of PTCAs were rated class III (inappropriate), whereas 24% were class III by use of the 1993 guidelines. Only 1.5% of CABG procedures were class III with ACC/AHA guidelines. By use of RAND guidelines, 12% of PTCA and 9% of CABG procedures were classified as inappropriate. CONCLUSIONS: Adherence to guidelines is higher when the recommendations are supported by evidence from randomized clinical trials (CABG). The credibility of the source and familiarity with the guidelines do not ensure compliance. When evidence is lacking, as with PTCA at the time of this study, guideline recommendations may lag behind appropriate changes in clinical practice. More frequent revisions coupled with on-line access have the potential to make guidelines more useful.

Aged↗
PubMed2003

Race and gender disparities in rates of cardiac revascularization: do they reflect appropriate use of procedures or problems in quality of care?

BACKGROUND: Numerous studies have documented substantial differences by race and gender in the use of coronary artery bypass graft surgery and percutaneous coronary angioplasty. However, few studies have examined whether these differences reflect problems in quality of care. METHOD: We selected a random sample stratified by gender, race, and income of 5026 Medicare beneficiaries aged 65 to 75 who underwent inpatient coronary angiography during 1991 to 1992 in 1 of 5 states. We compared the frequency of 2 problems in quality by race and gender: underuse or the failure to receive a clinically indicated revascularization procedure and receipt of revascularization when it was not clinically indicated. We used 2 independent sets of criteria developed by the RAND Corporation and the American College of Cardiology/American Hospital Association (ACC/AHA). We also examined survival of the cohort through March 31, 1994. RESULTS: Revascularization procedures were clinically indicated more frequently among whites than blacks and among men than women. Failure to receive revascularization when it was indicated was more common among blacks than among whites (40% vs. 23-24%, depending on the criteria, both P<0.001) but similar among men and women (25% vs. 22-24%, P>0.05). Racial disparities remained similar after adjusting for patient and hospital characteristics. Among patients rated inappropriate, use of procedures was greater for whites than blacks using RAND criteria (10.5% vs. 5.8%, P<0.01) and greater for men than for women (14.2% vs. 5.3% by RAND criteria, P=0.001; 8.2% vs. 4.0%% by ACC/AHA criteria, P=0.04). After multivariate adjustment, the disparities for race and gender remained similar and were statistically significant using RAND criteria. Mortality rates tended to validate our appropriateness criteria for underuse. CONCLUSIONS: Racial differences in procedure use reflect higher rates of clinical appropriateness among whites, greater underuse among blacks, and more frequent revascularization when it was not clinically indicated among whites. Underuse is associated with higher mortality. In contrast, men had higher rates of clinical appropriateness and were more likely to receive revascularization when it was not clinically indicated. There was no evidence of greater underuse among women.

Black or African American↗
PubMed2003

Primer on multiple regression models for diagnostic imaging research.

This article provides an introduction to multiple regression analysis and its application in diagnostic imaging research. We begin by examining why multiple regression models are needed in the evaluation of diagnostic imaging technologies. We then examine the broad categories of available models, notably multiple linear regression models for continuous outcomes and logistic regression models for binary outcomes. The purpose of this article is to elucidate the scientific logic, meaning, and interpretation of multiple regression models by using examples from the diagnostic imaging literature.

Confounding Factors, Epidemiologic↗