Chest Imaging

Fibrosing alveolitis

term used, primarily in the UK, to refer to usual interstitial pneumonia (UIP). In its early stages, this entity is characterized by an alveolitis and increased cellularity of the alveolar wall, with hyaline membrane involving alveolar spaces. As the disease progresses, fibrosis develops with organization of intra-alveolar exudates and incorporation of these into the alveolar wall. Honeycombing develops in the late stages. Fibrosing alveolitis represents a reaction of lung to injury rather than a disease per se; it can be idiopathic or seen in patients with collagen vascular diseases such as rheumatoid lung disease and progressive systemic sclerosis, asbestosis, and certain drug reactions. Clinically, the term cryptogenic fibrosing alveolitis is equivalent to idiopathic pulmonary fibrosis. The HRCT appearances of fibrosing alveolitis are the same as those of UIP. It is characterized by a predominance of reticular opacities, which correspond to areas of irregular fibrosis, lung destruction, Honeycombing and traction bronchiectasis. Ground glass opacities are usually related to the presence of alveolitis, alveolar wall thickening, or early fibrosis.

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