Intrathoracic manifestations of collagen vascular diseases are very common. The frequency of intrathoracic manifestations and the pattern of abnormality are variable depending on the type of collagen vascular disease and may simultaneously involve one or more of the following: lung parenchyma, airways, pulmonary vessels, pericardium, and pleura. Most significant manifestations include diffuse interstitial pneumonia and pulmonary hypertension which together represent the main causes of morbidity and mortality of these patients. Pulmonary, airway and pleural involvement may also be secondary to the therapy adopted for management of the disease, or result from bacterial pneumonia or opportunistic infection. In the present review, the authors summarize the main intrathoracic manifestations of collagen vascular diseases and the differential diagnosis on high-resolution chest computed tomography.

Keywords: Lung, Collagen vascular disease, Interstitial pneumonia, Pulmonary hypertension, Computed tomography

The recognition and differential diagnosis of the various patterns of abnormality seen on high-resolution computed tomography (HRCT) are important in the evaluation of patients with chronic insterstitial lung diseases. Various patterns of abnormality have been described in the literature, which sometimes are overlapped. Distinction between the various patterns can be difficult particularly for residents and radiologists who are not familiarized with these images. The authors illustrate the characteristic patterns of abnormality seen in chronic interstitial lung diseases and propose a simple interpretation algorithm based on the pattern and distribution of the findings. The algorithm includes the six main patterns of abnormality seen on HRCT: septal lines, reticular pattern, cystic pattern, nodular pattern, ground-glass opacities and consolidation.

Keywords: Interstitial lung disease, Lungs, Lung diseases, High-resolution computed tomography

We describe a target sign on chest CT characterized by a combination of peripheral ring-like opacity and a central nodular groundglass opacity surrounding a vessel in a couple with COVID-19 pneumonia confirmed by real-time reverse transcriptase fluorescence polymerase chain reaction sputum analysis.

Keywords: Coronavirus infection; Coronavirus; Computed tomography.