An observer study was performed on a set of 105 randomly selected chest CT scans obtained in a group of consecutive patients presenting to the emergency ward between March 14th 2020 and March 25th 2020 with suspected SARS-CoV-2 infection, in whom RT-PCR was performed. Patient inclusion, CT protocol, and radiation parameters are described in Supplement 2. Medical ethics committee approval was obtained prior to the study. Informed consent was waived, and data collection and storage were carried out in accordance with local guidelines.
Patient characteristics (age, gender, comorbidities), clinical follow up, including a multidisciplinary clinical diagnosis, if applicable, and RT-PCR results were extracted from electronic patient records. These data allowed stratification of all patients into one of the following three groups: patients with at least one positive RT-PCR result for SARS-CoV-2 within five days after CT (PCR+), patients with one or multiple negative RT-PCR results but a clinical diagnosis of COVID-19 according to clinical records (PCR-/Clinical+), and patients with one or multiple negative RT-PCR results and a clinical course not consistent with COVID-19, or consistent with an alternative diagnosis (PCR-/Clinical-).
Patient characteristics (age, gender, comorbidities), clinical follow up, including a multidisciplinary clinical diagnosis, if applicable, and RT-PCR results were extracted from electronic patient records. These data allowed stratification of all patients into one of the following three groups: patients with at least one positive RT-PCR result for SARS-CoV-2 within five days after CT (PCR+), patients with one or multiple negative RT-PCR results but a clinical diagnosis of COVID-19 according to clinical records (PCR-/Clinical+), and patients with one or multiple negative RT-PCR results and a clinical course not consistent with COVID-19, or consistent with an alternative diagnosis (PCR-/Clinical-).