Publication bias in diagnostic imaging: conference abstracts with positive conclusions are more likely to be published.

OBJECTIVE: To evaluate whether imaging diagnostic test accuracy conference abstracts with positive conclusions or titles are more likely to reach full-text publication than those with negative (or neutral) conclusions or titles. METHODS: Diagnostic accuracy research abstracts were included if they were presented at the 2011 or 2012 Radiological Society of North America conference. Full-text publication status at 5 years post conference abstract submission was determined. Conclusion and title positivity of conference abstracts were extracted, as well as potential confounding factors. The associations of conclusion and title positivity with publication status at 5 years post conference abstract submission were assessed using a multivariable logistic regression model. Conditional odds ratios were calculated to express the strength of associations, adjusting for the confounders. RESULTS: In total, 282/400 (71%) of included conference abstracts reached full-text publication. A total of 246 out of 337 (74%) conference abstracts with positive conclusions resulted in full-text publications, compared with 26/48 (54%) with neutral conclusions and 5/15 (33%) with negative conclusions. In multivariable logistic regression, conclusion positivity was significantly associated with full-text publication (odds ratio 3.6; 95% CI 1.9-6.7 for conference abstracts with positive conclusions, compared with those with non-positive conclusions); this did not apply to title positivity (odds ratio 1.2; 95% CI 0.47-3.0). CONCLUSION: Imaging conference abstracts with positive conclusions were more likely to be published as full-text articles. Title positivity was not associated with publication. This preferential publication pattern may lead to an overrepresentation of positive studies in the literature. An overrepresentation of positive studies may contribute to inflated estimates of test accuracy and has the potential to adversely influence patient care. KEY POINTS: • Imaging diagnostic test accuracy conference abstracts with positive conclusions were more likely to be reported as full-text articles than those with non-positive conclusions. • The majority (75%) of imaging diagnostic test accuracy conference abstracts with positive conclusions were published, compared with only 53% and 33% with neutral and negative conclusions, respectively. • Conclusion positivity remained associated with the full-text publication of conference abstracts when controlling for multiple potential confounding variables.

Macroscopic Fat in Adrenocortical Carcinoma: A Systematic Review.

OBJECTIVE. The objective of this systematic review was to determine the number and quality of reports of adrenocortical carcinoma (ACC) containing macroscopic fat; this information may inform guidelines for diagnosis and management of ACC. MATERIALS AND METHODS. A comprehensive search of databases of published studies was performed. Two reviewers independently selected original research, case series, or case reports of ACC with macroscopic fat on imaging and extracted data. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool. RESULTS. Three case reports and one retrospective study comprising a total of seven cases of ACC (lesion size: range, 6.5-22 cm) with macroscopic fat were included. ACC was symptomatic in all patients; neither locally invasive features nor metastases were reported. Four cases had less than 5% macroscopic fat on imaging, and the percentage fat on imaging was not reported for the remaining three cases. With regard to the risk of bias, one case had high risk for the index test domain because of potentially unreliable determination of macroscopic fat (i.e., no pathologic confirmation). All seven cases (from four studies) had unclear risk for the reference standard domain because there was insufficient information about the reference standard to determine whether ACC was correctly diagnosed. All studies were at low risk of bias in the flow and timing domain. CONCLUSION. There are few reports of macroscopic fat in ACC detected on imaging studies; among the reports of macroscopic fat in ACC, tumors were large (> 6 cm) and had a small proportion of gross fat (< 5%). The reliability of reported cases is questionable primarily because of insufficient details about pathologic diagnosis. Based on this information, a change in guideline recommendations may not be warranted. However, consideration of follow-up or biopsy of patients with large symptomatic tumors (> 6 cm) containing a small proportion of fat (< 5%) may be appropriate.

Publication Bias: Association of Diagnostic Accuracy in Radiology Conference Abstracts with Full-Text Publication.

Background Recent investigations have identified a faster time to publication for imaging studies with higher diagnostic test accuracy (DTA), but it is unknown whether such studies are more likely to be published. A higher probability of full-text publication for studies with higher DTA could have negative consequences on clinical decision making and patient care. Purpose To evaluate the proportion of imaging diagnostic accuracy studies presented as conference abstracts that reach full-text publication and to identify whether there is an association between diagnostic accuracy and full-text publication in peer-reviewed journals within 5 years after abstract submission. Materials and Methods Diagnostic accuracy research abstracts presented at the Radiological Society of North America (RSNA) Annual Meeting in 2011 and 2012 were evaluated between September 1, 2017, and January 11, 2018. Sensitivity and specificity from the abstracts were used to calculate the Youden index (sensitivity + specificity-1); additional abstract characteristics were extracted. To identify full-text publications within 5 years after abstract submission, PubMed and Google Scholar were searched, and authors were contacted. Logistic regression analysis was used to assess for associations between higher diagnostic accuracy and full-text publication. Results A total of 7970 abstracts were evaluated, and 405 were included. Of these, 288 (71%) reached full-text publication within 5 years after abstract submission. Logistic regression analysis accounting for several confounding variables failed to show an association between reported Youden index in the conference abstract and probability of full-text publication (odds ratio, 1.01; 95% confidence interval: 0.99, 1.02; P = .21). Conclusion More than a quarter of abstracts presented at the RSNA Annual Meeting do not reach full-text publication in peer-reviewed journals. The magnitude of reported diagnostic accuracy was not associated with full-text publication, which is consistent with results of diagnostic accuracy studies in other medical specialties. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Fielding in this issue.