Ground-glass opacity (GGO): a review of the differential diagnosis in the era of COVID-19

Thoracic imaging is fundamental in the diagnostic route of Coronavirus disease 2019 (COVID-19) especially in patients admitted to hospitals. In particular, chest computed tomography (CT) has a key role in identifying the typical features of the infection. Ground-glass opacities (GGO) are one of the main CT findings, but their presence is not specific for this viral pneumonia. In fact, GGO is a radiological sign of different pathologies with both acute and subacute/chronic clinical manifestations. In the evaluation of a subject with focal or diffuse GGO, the radiologist has to know the patient's medical history to obtain a valid diagnostic hypothesis. The authors describe the various CT appearance of GGO, related to the onset of symptoms, focusing also on the ancillary signs that can help radiologist to obtain a correct and prompt diagnosis.

Automated summary

Thoracic imaging, especially chest CT, plays a key role in diagnosing COVID-19 in hospitalized patients. Ground-glass opacities on CT scans are a common finding, but not specific to viral pneumonia. Radiologists need to consider the patient's medical history in order to accurately diagnose different pathologies with GGOs. Additional signs can help radiologists make correct and prompt diagnoses.