Chapter 9 Diseases of Altered Immunologic Activity
IMMUNE REACTIONS
GOODPASTURE’S SYNDROME
CONNECTIVE TISSUE DISEASES
Rheumatoid Disease
Interstitial Fibrosis and Pneumonitis
The radiologic features of rheumatoid interstitial disease are usually identical to those seen in UIP (Fig. 9-3) and NSIP. In the early stages, a pattern of fine linear or irregular opacities can be identified predominantly in the bases, which may progress to coarse reticulation with end-stage cystic changes and honeycombing. CT findings include reticular opacities located predominantly in the subpleural regions in the lung bases; ground-glass attenuation (especially in NSIP) (Fig. 9-4); irregular pleural and mediastinal interfaces; thickened interlobular septa; and honeycomb cysts (especially in UIP). Progressive loss of volume (“shrinking lungs”) may be observed on serial studies. Pleural effusion or thickening may be present. Occasionally, other features of rheumatoid disease may be observed in the bony thorax, including typical arthritic changes in the shoulder, joints, and tapering of the distal clavicles.
Progressive Systemic Sclerosis: Scleroderma
Characteristics
Radiographic Features
Other nonpulmonary manifestations of scleroderma may be identified on the chest radiograph. Calcinosis may be present in the skin and subcutaneous tissue of the thorax, particularly about the shoulders. Atrophy and atony of the esophagus that results in absent peristalsis may also lead to dilation of the esophagus. On chest radiography and CT, this is manifested by the presence of gas without an air-fluid level in a distended esophagus, the so-called air esophagram (see Fig. 9-6). Dilation of the central pulmonary arteries with rapid tapering of peripheral vessels is characteristic of pulmonary arterial hypertension (Fig. 9-7).