Background The respiratory illness caused by SARS‐CoV‐2 infection continues to present diagnostic challenges. Our 2020 edition of this review showed thoracic (chest) imaging to be sensitive and moderately specific in the diagnosis of coronavirus disease 2019 (COVID‐19). In this update, we include new relevant studies, and have removed studies with case‐control designs, and those not intended to be diagnostic test accuracy studies. Objectives To evaluate the diagnostic accuracy of thoracic imaging (computed tomography (CT), X‐ray and ultrasound) in people with suspected COVID‐19. Search methods We searched the COVID‐19 Living Evidence Database from the University of Bern, the Cochrane COVID‐19 Study Register, The Stephen B. Thacker CDC Library, and repositories of COVID‐19 publications through to 30 September 2020. We did not apply any language restrictions. Selection criteria We included studies of all designs, except for case‐control, that recruited participants of any age group suspected to have COVID‐19 and that reported estimates of test accuracy or provided data from which we could compute estimates. Data collection and analysis The review authors independently and in duplicate screened articles, extracted data and assessed risk of bias and applicability concerns using the QUADAS‐2 domain‐list. We presented the results of estimated sensitivity and specificity using paired forest plots, and we summarised pooled estimates in tables. We used a bivariate meta‐analysis model where appropriate. We presented the uncertainty of accuracy estimates using 95% confidence intervals (CIs). Main results We included 51 studies with 19,775 participants suspected of having COVID‐19, of whom 10,155 (51%) had a final diagnosis of COVID‐19. Forty‐seven studies evaluated one imaging modality each, and four studies evaluated two imaging modalities each. All studies used RT‐PCR as the reference standard for the diagnosis of COVID‐19, with 47 studies using only RT‐PCR and four studies using a combination of RT‐PCR and other criteria (such as clinical signs, imaging tests, positive contacts, and follow‐up phone calls) as the reference standard. Studies were conducted in Europe (33), Asia (13), North America (3) and South America (2); including only adults (26), all ages (21), children only (1), adults over 70 years (1), and unclear (2); in inpatients (2), outpatients (32), and setting unclear (17). Risk of bias was high or unclear in thirty‐two (63%) studies with respect to participant selection, 40 (78%) studies with respect to reference standard, 30 (59%) studies with respect to index test, and 24 (47%) studies with respect to participant flow. For chest CT (41 studies, 16,133 participants, 8110 (50%) cases), the sensitivity ranged from 56.3% to 100%, and specificity ranged from 25.4% to 97.4%. The pooled sensitivit...

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To assess whether primary diagnostic accuracy studies with positive conclusions or titles are cited more frequently than those with negative (or neutral) conclusions or titles in the imaging diagnostic accuracy literature.

Background Ferumoxytol has been studied as an alternative to gadolinium‐based MRI contrast agents, but regulatory body warnings currently limit its use. Purpose Estimate the adverse event rate in patients undergoing MRI with ferumoxytol as a contrast agent. Study Type Systematic review. Population Thirty‐nine studies including 5411 ferumoxytol administrations in 4336 patients. Assessment Multiple databases were searched for studies using ferumoxytol as an off‐label MRI contrast agent in any patient population as of April 2020. Studies were eligible for inclusion if they reported the number and severity of adverse events (classified by American College of Radiology [ACR] severity of acute reactions). Risk of bias was assessed using the ROBINS‐I tool. Statistical Tests The proportion of administrations with adverse events was calculated using random effects meta‐analysis of proportions. Results No deaths related to ferumoxytol administration were reported. Sixteen studies reported immediate adverse events in 3849 patients undergoing 4901 ferumoxytol administrations. Ninety‐seven immediate adverse events were reported and the pooled adverse event proportion for immediate adverse events was 0.02 (95% confidence interval [CI] 0.02–0.02). Twenty‐three studies reported time‐unspecified adverse events in 487 patients undergoing 510 ferumoxytol administrations. Five time‐unspecified adverse events were reported; the pooled adverse event proportion for time‐unspecified adverse events was 0.01 (95% CI 0.00–0.04). 88% of adverse events were mild (90/102), 11% (11/102) were moderate, and 1% (1/102) was severe. Sixteen studies were at low risk of bias, 23 studies were at serious risk of bias. Subgroup analysis by patient population revealed no significant variability (adult vs. pediatric). No studies evaluated the use of ferumoxytol as an alternative to patients who had a prior hypersensitivity reaction to gadolinium‐based contrast agents (GBCAs). Data Conclusion The overall adverse event rate for off‐label ferumoxytol use as an MRI contrast agent is 2%, with rare severe reactions and no deaths. To date, there are no studies evaluating the safety of ferumoxytol as an alternative to GBCAs in patients with a prior hypersensitivity reaction. Level of Evidence 2 Technical Efficacy Stage 5