Detection and Diagnostic Overall Accuracy Measures of Medical Tests.

BACKGROUND: Overall accuracy measures of medical tests are often used with unclear interpretations. OBJECTIVES: To develop methods of calculating the overall accuracy of medical tests in the patient population. METHODS: Algebraic equations based on Bayes' theorem. RESULTS: A new approach is proposed for calculating overall accuracy in the patient population. Examples and applications using published data are presented. CONCLUSIONS: The overall accuracy is the proportion of the correct test results. We introduce a clear distinction between the overall accuracy measures of medical tests that are aimed at the detection of a disease in a screening of populations for public health purposes in the general population and the overall accuracy measures of tests aimed at determining a diagnosis in individuals in a clinical setting. We show that the overall detection accuracy measure is obtained in a specific study that explores test accuracy among persons with known diagnoses and may be useful for public health screening tests. It is different from the overall diagnostic accuracy that could be calculated in the clinical setting for the evaluation of medical tests aimed at determining the individual patients' diagnoses. We show that the overall detection accuracy is constant and is not affected by the prevalence of the disease. In contrast, the overall diagnostic accuracy changes and is dependent on the prevalence. Moreover, it ranges according to the ratio between the sensitivity and specificity. Thus, when the sensitivity is greater than the specificity, the overall diagnostic accuracy increases with increasing prevalence, and vice versa, that is, when the sensitivity is lower than the specificity, the overall diagnostic accuracy decreases with increasing prevalence so that another test might be more useful for diagnostic procedures. Our paper suggests a new and more appropriate methodology for estimating the overall diagnostic accuracy of any medical test. This may be important for helping clinicians avoid errors.

Cardiac Fibroma in an Adult AIRP Best Cases in Radiologic-Pathologic Correlation.

Editor's Note.-RadioGraphics continues to publish radiologic-pathologic case material selected from the American Institute for Radiologic Pathology (AIRP) "best case" presentations. The AIRP conducts a 4-week Radiologic Pathology Correlation Course, which is offered five times per year. On the penultimate day of the course, the best case presentation is held at the American Film Institute Silver Theater and Cultural Center in Silver Spring, Md. The AIRP faculty identifies the best cases from each organ system, brought by the resident attendees. One or more of the best cases from each of the five courses are then solicited for publication in RadioGraphics. These cases emphasize the importance of radiologic-pathologic correlation in the imaging evaluation and diagnosis of diseases encountered at the institute and its predecessor, the Armed Forces Institute of Pathology (AFIP).

Diagnosis of Ovarian Torsion: Is It Time to Forget About Doppler?

OBJECTIVE: Accuracy of ultrasound in diagnosis of ovarian torsion remains controversial, with some studies reporting correct diagnosis in only 23% to 66% of cases. Normal Doppler flow does not necessarily exclude an ovarian torsion; in fact, it may lead to missing the diagnosis and has been show to delay management. The objective of our study was to assess sensitivity and specificity of ultrasound diagnosis of ovarian torsion and to analyze the factors contributing to correct and incorrect diagnosis. METHODS: All women presenting with abdominal pain and admitted for urgent/emergent surgery to the gynaecology service at a major teaching hospital between September 2010 and August 2015 were reviewed. Of those, 55 cases of surgically proven ovarian torsion and 48 control cases were selected. Ultrasound reports were reviewed and analyzed. RESULTS: Sixty-one percent of right ovarian torsion case and 27% of left ovarian torsion cases had normal Doppler flow. Presence of ovarian cysts was significantly associated with torsion. Sensitivity of ultrasound was 70% and specificity was 87%. CONCLUSION: While ultrasound can be used to support a diagnosis of ovarian torsion, it is a clinical diagnosis that requires integration of many factors, especially patient presentation and exclusion of other non-gynaecological pathologies. Doppler flow is not a useful variable to diagnose or exclude ovarian torsion and we recommend it should not be used to exclude a diagnosis of ovarian torsion.

The Risk of Cancer Might be Lower Than We Think. Alternatives to Lifetime Risk Estimates.

BACKGROUND: Estimates of lifetime cancer risk are commonly used in the clinical setting and in health-care evaluations. These measures are based on lifetime cancer risk estimates and may create an unrealistically frightening perception of cancer risk for an individual. We suggest using two new measures of cancer risk to complement the cancer lifetime risk measure, namely estimates of cancer risk from birth to a specific age or from a specific age to life expectancy. METHODS: We calculated risks using incidence density data from the Israel National Cancer Registry of 2013, applying a well-known formula for calculating risk, for a follow-up time. The joint disease-free survival probability is calculated for several age intervals, and hence the risk (i.e. 1-survival) for the intervals. RESULTS: The risk of cancer to age 80 in Jewish men and women, respectively, ranged from about 0.336 and 0.329 at age 0, to 0.279 and 0.237 at age 60. The risk of cancer from birth up to an age in Jewish men and women, respectively, ranged from 0 and 0 at birth to 0.088 and 0.129 at age 60. The risk of cancer to age 80 in Arab men and women, respectively, ranged from 0.298 and 0.235 at age 0 to 0.249 and 0.161 at age 60. The risk of cancer from birth up to an age in Arab men and women, respectively, ranged from 0 and 0 at age 0 to 0.074 and 0.095 at age 60. In Jewish and Arab women, breast cancer risk to age 80 decreased from about 0.127 in Jewish women at age 40 to 0.079 at age 60 and from 0.080 to 0.043 in Arab women; the risk from birth up to a specific age ranged between 0 and 0.056, and 0 and 0.040, respectively. CONCLUSION: The two proposed new estimates convey important additional information to patients and physicians. These estimates are considerably lower than the frequently quoted 33% lifetime cancer risk and are more relevant to patients and physicians. Similarly, breast cancer risk estimates up to or from a specific age differ considerably from the frequently quoted lifetime risk estimates of 1 in 8 women.

Imaging Intra-abdominal Burkitt's Lymphoma: From Discrete Bowel Wall Thickening to Diffuse Soft Tissue Infiltration.

Burkitt's lymphoma is a highly aggressive non-Hodgkin's B-cell lymphoma, which often presents with intra-abdominal involvement. The purpose of this pictorial review is to illustrate the various intra-abdominal imaging findings of Burkitt's lymphoma. Extranodal disease at presentation is common, including involvement of the bowel, stomach, pancreas, spleen, and mesentery.

Clinical Aspects and Current Evidence Base for Transcatheter Aortic Valve Implantation.

Aortic stenosis (AS) is a common disorder that affects nearly 5% of individuals over 75 years of age. Many patients with AS are unable to undergo surgical valve replacement (SAVR) as they are commonly deemed to be of very high risk. Transcatheter aortic valve implantation (TAVI), introduced in 2002, is a new method for treatment of these patients. Computed tomography (CT) is becoming the gold standard imaging modality for preprocedural planning, including assessment of annular size and access. Since 2002, >100,000 procedures have been performed with either a balloon-expandable valve (Edwards SAPIEN valve) or the self-expanding valve (Medtronic CoreValve). A growing body of evidence supporting the effectiveness and safety of TAVI includes the PARTNER trial and the CoreValve pivotal trial. These have found significantly better survival for the TAVI arm compared with SAVR (CoreValve). There were no significant differences in all-cause mortality between TAVI and SAVR, whereas significantly reduced all-cause mortality was observed for TAVI when compared with standard therapy (PARTNER). Paravalvular regurgitation is increased in TAVI compared with SAVR; however, integration of CT into valve selection has shown to improve outcomes. There is conflicting evidence regarding increased risk for stroke after TAVI, and occurrence of conduction disturbances and the need for a pacemaker after TAVI remain a concern. Upcoming trials are focusing on assessing outcomes for use of TAVI in intermediate-operative risk patients. The future will likely include an increased choice of devices, smaller access sites, and further integration of CT for preprocedure planning.

Inconsistent measurement of acute coronary syndrome patients' pre-hospital delay in research: a review of the literature.

BACKGROUND: Patients' treatment-seeking delay remains a significant barrier to timely initiation of reperfusion therapy. Measurement of treatment-seeking delay is central to the large body of research that has focused on pre-hospital delay (PHD), which is primarily patient-related. This research has aimed to quantify PHD and its effects on morbidity and mortality, identify contributing factors, and evaluate interventions to reduce such delay. A definite time of symptom onset in acute coronary syndrome (ACS) is essential for determining delay, but difficult to establish. This literature review aimed to explore the variety of operational definitions of both PHD and symptom onset in published research. METHODS AND RESULTS: We reviewed the English-language literature from 1998-2013 for operational definitions of PHD and symptom onset. Of 626 papers of possible interest, 175 were deemed relevant. Ninety-seven percent reported a delay time and 84% provided an operational definition of PHD. Three definitions predominated: (a) symptom onset to decision to seek help (18%); (b) symptom onset to hospital arrival (67%), (c) total delay, incorporating two or more intervals (11%). Of those that measured delay, 8% provided a definition of which symptoms triggered the start of timing. CONCLUSION: We found few and variable operational definitions of PHD, despite American College of Cardiology/American Heart Association recommendations to report specific intervals. Worryingly, definitions of symptom onset, the most elusive component of PHD to establish, are uncommon. We recommend that researchers (a) report two PHD delay intervals (onset to decision to seek care, and decision to seek care to hospital arrival), and (b) develop, validate and use a definition of symptom onset. This will increase clarity and confidence in the conclusions from, and comparisons within and between studies.

Assessment of sex differences in plaque morphology by coronary computed tomography angiography--are men and women the same?

PURPOSE: The objective of this study was to assess whether sex differences exist in plaque burden and plaque subtype as assessed by coronary computed tomography angiography (CCTA). METHODS: The study cohort included 937 consecutive patients who underwent CCTA between 2008 and 2010. Stenosis was quantified using the Society of Cardiovascular Computed Tomography stenosis grading scale and a total stenosis score (TSS) was generated. Plaque morphology (PM) was reported as predominantly calcified (CP), noncalcified (NCP), or mixed (MP) plaque, and CP, NCP, and MP percentages were calculated. RESULTS: On multivariate analysis, men were significantly more likely to have plaque (65.9% of men vs. 44.6% of women, p<0.001), at least one segment with ≥50% stenosis (22.7% of men vs. 10.3% of women, p<0.001) and higher TSS (mean score=2.81 for men vs. 1.58 for women, p<0.001). Sex was the strongest predictor in all models (odds ratio [OR]=2.55, 95% confidence interval [CI] 1.78-3.67, p<0.001 for any plaque; OR=2.48, 95% CI 1.48-4.16, p<0.01 for segments with ≥50% stenosis; ß=1.46, 95% CI 0.69-2.22, p<0.001 for TSS). Among patients with coronary plaque present, no significant sex differences in PM were found. CONCLUSIONS: Sex was the strongest risk factor for the presence and extent of plaque. Significant sex differences in PM did not exist.

A prospective randomized trial comparing image quality, study interpretability, and radiation dose of narrow acquisition window with widened acquisition window protocols in prospectively ECG-triggered coronary computed tomography angiography.

BACKGROUND: Prospectively triggered coronary computed tomography angiography (CTA) is commonly performed with a widened acquisition window to provide flexibility in image reconstruction. OBJECTIVE: We conducted a randomized controlled trial to determine whether the use of a narrow acquisition window in prospectively triggered coronary CTA would allow lower radiation dose while preserving image quality and interpretability. METHODS: Prospective 2-center 2- platform randomized trial that evaluated 205 consecutive patients 96 with widened acquisition (WA) and 109 narrow acquisition (NA) referred for coronary CTA in sinus rhythm and heart rate <65 beats/min. Patients scanned with WA had phases reconstructed at 5% intervals, and each phase was assigned an individual study ID. Images were reviewed with individual phase reconstructions interpreted randomly by 2 level 3 readers with a third for consensus. Images were evaluated with a 5-point Likert scale on a per-vessel basis (best score on any phase). Scores were then dichotomized into diagnostic (score 3-5) compared with nondiagnostic (score 1-2). Readers also reported obstructive coronary artery disease on a per-patient basis. Agreement for the diagnosis of obstructive disease and per-artery interpretability was performed. Signal and noise measurements were also performed. RESULTS: No difference in demographics between groups (P = NS). The signal-to-noise ratio was comparable 12.99 ± 3.4 NA and 12.53 ± 4.13 for the WA (P = 0.45). The median effective dose was 1.78 mSv for NA compared with 3.26 mSv for WA (P < 0.001). Image quality, diagnostic interpretability, interreader agreement, and downstream testing were not significantly different between the 2 groups (P= NS for all). CONCLUSIONS: Coronary CTA with NA resulted in a 47% lower radiation dose without significant difference in study interpretability or image quality or increased downstream resource use or testing.

Cardiovascular risk among stable individuals suspected of having coronary artery disease with no modifiable risk factors: results from an international multicenter study of 5262 patients.

PURPOSE: To assess the prevalence, extent, severity, and risk of coronary artery disease (CAD) in patients suspected of having CAD but with no medically modifiable risk factors. MATERIALS AND METHODS: Institutional review board approval or waiver of consent was obtained at each center. This study was HIPAA compliant. From an international multicenter cohort study of 27 125 subjects undergoing coronary computed tomographic (CT) angiography from 12 centers, 5262 patients without known CAD and without modifiable risk factors were identified. CAD severity was defined as none (0%), mild (1%-49%), or obstructive (≥ 50%) on a per-patient, per-vessel, and per-segment basis. CAD presence, extent, and severity were related to incidence of major adverse cardiovascular event (MACE) by using Cox proportional hazards models. RESULTS: At a mean follow-up of 2.3 years ± 1.2 (standard deviation), MACE occurred in 106 patients. CAD was common for nonobstructive (n = 1452, 27%) and obstructive (n = 629, 12%) CAD. In risk-adjusted analysis, per-patient obstructive CAD (hazard ratio [HR], 6.64; 95% confidence interval [CI]: 3.68, 12.00; P ≤ .001) was related to MACE. MACE was associated with a dose-response relationship to the number of vessels exhibiting obstructive CAD, increasing risk for obstructive one-vessel (HR, 6.11; 95% CI: 3.22, 11.6; P ≤ .001), two-vessel (HR, 5.86; 95% CI: 2.75, 12.5; P ≤ .0001), or three-vessel or left main (HR, 11.69; 95% CI: 5.38, 25.4; P ≤ .001) CAD. The increased hazard for MACE of obstructive disease holds true for symptomatic (HR, 11.9; 95% CI: 4.81, 29.6; P ≤ .001) and asymptomatic (HR, 6.3; 95% CI: 2.4, 16.7; P ≤ .001) patients. No CAD at coronary CT angiography was associated with a low annualized MACE rate: 0.31% versus 2.06% with obstructive disease. CONCLUSION: Among individuals suspected of having CAD but without modifiable risk factors, CAD is common, with significantly increased hazards for MACE and mortality.

Modeling of fractional flow reserve based on coronary CT angiography.

Fractional flow reserve (FFR) at the time of invasive coronary angiography is the current gold standard for determination of ischemia. Coronary CT angiography (coronary CTA) has emerged as an effective noninvasive method for direct visualization of coronary artery disease. However, severe stenosis by coronary CTA are only modestly predictive of ischemia. Recent technological innovations enable non-invasive calculation of FFR from CT. FFRCT is superior to anatomic assessment of stenoses in coronary CTA for the diagnosis of ischemia-causing lesions on both a per-patient and a per-vessel basis. FFRCT improves the diagnostic accuracy mostly by reducing the false positive rate of stenosis assessment alone. Furthermore, in patients where CT demonstrates an intermediate stenosis, FFRCT demonstrates significantly higher diagnostic performance than anatomic assessment alone.

Ethnic and gender differences in patient education about heart disease risk and prevention.

OBJECTIVE: To investigate whether there are gender and ethnic disparities in the patient education provided by primary healthcare providers about heart disease (HD) risk and prevention. METHODS: A telephone survey, conducted in four languages, was completed by 976 people, 40+ years of age, in Metro Vancouver, Canada. Questions assessing communication with healthcare providers' provision of HD risk and management education were the focus. RESULTS: Statistically significant gender and ethnic differences were found. Women were less likely to report discussing HD risk and management with their healthcare providers. Chinese-Canadian participants had less likelihood of receiving HD education compared with participants of other ethnic origins. These differences persisted after multivariate adjustment with income, highest level of education attained, age, and other factors. CONCLUSION: Primary healthcare providers should make improved efforts towards education about HD and its risk factors for women in general, and for postmenopausal women especially. PRACTICE IMPLICATIONS: Healthcare providers should be aware that some ethnic populations may not be receiving patient education similar to that received by people of other communities, as found for Chinese-Canadian members of this study community. Further understanding of the barriers faced by ethnic groups must be gained to develop solutions.

Ethnic and gender differences in perceptions of mortality risk in a Canadian urban centre.

BACKGROUND: Women reportedly do not perceive heart disease (HD) as a major threat to their health; however, men's perceptions are rarely studied. PURPOSE: We explored gender and ethnic differences in risk perception of HD mortality. METHODS: The survey was completed by 976 people 40+ years of age, in metropolitan Vancouver, Canada. RESULTS: Men, compared with women, were more likely not to know the answer to a question about whether HD is the most common cause of death for women; however, women were more likely not to know the answer to a question about whether HD is the most common cause of death for men. Chinese-Canadian and South Asian-Canadian participants were more likely than participants of other ethnic groups not to know the answer to either question, and the Chinese-Canadian participants were more likely to disagree that HD is the most common cause of death for women. CONCLUSION: There is a need to educate the Chinese-Canadian and South Asian-Canadian communities about HD as a first step in promoting health behavior change. Men and women must be educated about the other gender's risk of HD because all adults play integral roles in making decisions about the prevention of and early intervention for HD.

Is early- and late-onset depression after acute myocardial infarction associated with long-term survival in older adults? A population-based study.

BACKGROUND: Early-onset depression after acute myocardial infarction (AMI) affects short-term survival in clinical samples of patients. There is no information on the impact of early-onset depression or late-onset depression on long-term survival. OBJECTIVE: To investigate the impact of early- and late-onset depression on survival using administrative data. METHODS: A historical inception cohort design was used, commencing in 1994 with up to eight years of follow-up. A province-wide administrative data set from British Columbia was used to select the cohort and construct the variables. Data regarding hospitalizations, physician visits and prescription drugs were available. All individuals 66 years of age and older who had an AMI in 1994 or 1995 were selected (n=4874). Individuals were categorized as depressed, possibly depressed or not depressed based on physician or hospital visits indicating depression as a diagnosis and/or prescriptions for antidepressants. Early-onset depression was assessed during the first six months post-AMI, and late-onset depression was assessed between six months and five years post-AMI. All-cause mortality up to eight years post-AMI was the outcome. RESULTS: Both early- and late-onset depression were associated with long-term mortality. The hazard ratio was 1.34 (95% CI 1.04 to 1.73) for early-onset depression and 1.79 (95% CI 1.38 to 2.35) for late-onset depression. CONCLUSIONS: Both early- and late-onset depression post-AMI were significantly associated with mortality up to eight years post-AMI. Depression is a strong independent predictor of post-AMI mortality in older adults.