State-of-the-Art Imaging of the Lung for Connective Tissue Disease (CTD)

Involvement of the respiratory system is common in connective tissue diseases (CTDs), and the resultant lung injury can affect every part of the lung: the pleura, alveoli, interstitium, vasculature, lymphatic tissue, and large and/or small airways. Most of the parenchymal manifestations of CTD are similar to those found in interstitial lung diseases (ILDs), especially idiopathic interstitial pneumonias, and can be classified using the same system. Although there is some overlap, each CTD is associated with a characteristic pattern of pulmonary involvement. For this reason, thin-section CT as well as pulmonary function tests and serum markers are utilized for diagnosis, disease severity assessment, and therapeutic efficacy evaluation of ILD associated with CTD. In addition, newly developed pulmonary magnetic resonance imaging (MRI) procedures have been recommended as useful alternative imaging options for patients with CTD. This review article will (1) address radiological findings for chest radiography and conventional or thin-section CT currently used for six major types of CTD, rheumatoid arthritis, scleroderma (progressive systemic sclerosis), polymyositis/dermatomyositis, systemic lupus erythematosus, Sjögren syndrome and mixed connective tissue disease; (2) briefly deal with radiation dose reduction for thin-section CT examination; and (3) discuss clinically applicable or state-of-the-art MR imaging for CTD patients.