Thoracic imaging tests for the diagnosis of COVID-19

Abstract

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...

Real-life clinical sensitivity of SARS-CoV-2 RT-PCR test in symptomatic patients

“…Another small study found an 86.2% RT-PCR sensitivity in symptomatic COVID-19 patients in comparison with convalescent antibody [ 24 ]. Interestingly, a recent Cochrane meta-analysis on thoracic imaging of COVID-19 patients found an 87.9% pooled sensitivity for chest CT and 80.6% for chest X-ray [ 25 ]. However, diagnostic imaging is mainly performed on inpatients that can overestimate the sensitivity.…”

Elevated procalcitonin concentrations in severe Covid-19 may not reflect bacterial co-infection

“…Patients with active Covid-19 were defined as those with positive real-time reverse transcriptasepolymerase chain reaction (RT-PCR) assay for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) on nasopharyngeal swab or those being treated for suspected Covid-19 on clinical and radiological evidence of Covid-19 on chest radiograph or computed tomography. 6 Patient demographics and co-morbidities classified using the Charlson comorbidity index were extracted from patient records and our local clinical coding department. 7 The peak PCT concentration recorded during the critical care admission was used, with a cut-off value of 0.5 ng/dL as per local laboratory guidelines.…”

Diagnostic accuracy and inter-observer agreement with the CO-RADS lexicon for CT chest reporting in COVID-19

“…Many radiological societies have advised not to use CT chest for disease screening, especially in asymptomatic patients, as the CT scan has low specificity in differentiating other non-COVID-19 lung infections that could have similar CT chest findings [3,4]. However, recent Cochrane systematic review reported a sensitivity of 87.9% and a higher specificity of 80% in diagnosis of COVID-19 indicating that accuracy may be sufficient for there to be a role for CT in the diagnostic pathway for COVID-19 patients [5].…”