Rheumatoid arthritis: spectrum of computed tomographic findings in pulmonary diseases.

Rheumatoid arthritis (RA) is a common systemic disease that manifests as inflammatory arthritis of multiple joints. Interstitial lung disease (ILD) is the most common manifestation of rheumatoid lung disease. The ILDs associated with RA are diverse and it is very important for the general radiologist to differentiate one from another. There are many other pulmonary diseases apart from ILD. These are associated with a wide spectrum of morphologic changes with substantially different prognoses. The diagnosis of most of these diseases is by clinicoradiological correlation and some of them need pathologic correlation. High-resolution computed tomography helps to characterize and determine the extent of ILD in RA. When interpreting the high-resolution computed tomography of the chest in RA, the radiologist should be familiar with the findings in each entity and comment on activity of the disease, which helps in assessing the prognosis and need for active intervention. This pictorial essay reviews the spectrum of pulmonary diseases in RA and their differential diagnosis.