Normal chest CT in 1091 symptomatic patients with confirmed Covid-19: frequency, characteristics and outcome

Abstract

Objective Frequency of normal chest CT in symptomatic COVID-19 patients as well as the outcome of these patients remains unknown. The objectives of this work were to assess the incidence of initially normal chest CT in a cohort of consecutive confirmed COVID-19 patients with respiratory symptoms and to compare their clinical characteristics and their outcome to matched patients with typical COVID-19 lesions at initial CT. Methods From March 6 th to April 22 nd , all consecutive adult patients referred to the COVID-19 clinic of our Emergency Department were retrospectively analyzed. Each patient with a positive SARS-CoV-2 RT-PCR and a normal initial chest CT after second reading was 1:1 matched based on sex, age and date of CT acquisition to a patient with positive RT-PCR and initial chest CT with typical COVID-19 lesions. Clinical data, laboratory results and outcomes (major being mechanical ventilation and/ or death) were compared between both groups, using Wilcoxon signed-rank test, McNemar's chi-squared test and/or exact McNemar's test where appropriate. Results Fifty-seven chest CT out of 1091 (5.2%, 95% CI 4.0-6.7) in symptomatic patients with positive RT-PCR were normal, with a median onset of symptoms of 4.5 days (IQR [1.25-10.25]). After a median follow-up of 43 days, death and/or mechanical ventilation occurred in 3 patients (5.3%) in the study group, versus 11 (19.3%) in the control group (p = 0.011). Conclusions Normal initial chest CT occurred in 5.2% of symptomatic confirmed COVID-19 cases in our cohort. While better than those with abnormal chest CT, outcome was not entirely benign with 5.3% death and/or mechanical ventilation. Key Points• In a cohort of 1091 symptomatic COVID-19 patients, initial chest CT was normal in 5.2% of cases.• Normal chest CT in confirmed COVID-19 is frequent even when onset of symptoms is greater than 3 days.• The outcome of COVID-19 patients with initial normal chest CT, while better than those with abnormal CT, was not entirely benign with 5.3% death and/or mechanical ventilation. Keywords Diagnostic imaging . Multidetector computed tomography . Lung diseases . COVID-19 . Reverse transcriptase polymerase chain reaction Abbreviations CT Computed tomography ED Emergency department ICU Intensive care unit RT-PCR Reverse transcriptase polymerase chain reaction * Mickaël Ohana

Imaging and Clinical Features of COVID-19 Breakthrough Infections: A Multicenter Study

“…The differences in the frequency of COVID-19 pneumonia on CT observed in the three study groups may explain disease severity differences during hospitalization. In a study that examined clinical outcomes according to presence or absence of pneumonia in symptomatic COVID-19 patients, Leonard-Lorant et al found that the clinical outcomes of COVID-19 patients with an initially pneumonia-negative CT were better than those with a positive finding (25). In addition, several previous studies have reported that patients with extensive pneumonia on CT have a poorer prognosis (26)(27)(28).…”

Value of Laboratory Indicators in Predicting Pneumonia in Symptomatic COVID-19 Patients Infected with the SARS-CoV-2 Omicron Variant

“…[5][6][7] Pneumonia is a common cause of hospitalization and death in COVID-19 patients, and computed tomography (CT) images play a vital role in determining the severity and extent of the disease. [8][9][10][11][12] However, the incidence of pneumonia in Omicron itself is low, not all patients can receive immediate CT screening during a pandemic, and it is not necessary to perform CT scans on all Omicron-infected patients. In addition, the CT suites are high-risk areas for hospital-related transmission of COVID-19 and require infection control.…”

Usefulness of chest X-rays for detecting COVID 19 pneumonia during the SARS-CoV-2 pandemic

“…An initial negative chest X-ray or CT does not exclude the diagnosis of SARS-CoV-2 infection, as an infected patient can have a normal imaging test in the early stages of the disease and become positive later. 11 , 14 , 15 …”