S J Wadsworth, MRCP, FRCR and
D M Hansell, MRCP, FRCR
Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK
Summary
In established fibrosing alveolitis, there is a reticulo-nodularpattern most marked at the bases on chest radiography; patchyor diffuse ground glass opacification is a less common finding.
High resolution CT accurately depicts the macroscopic appearancesof CFA. A basal subpleural reticular pattern admixed with areasof apparently normal lung is typical; there may be ground glassopacification, tractional dilatation of airways and honeycombing.
In CFA the interpretation of ground glass opacification onHRCTis not straightforward. The relative proportions, ratherthanthe absolute severity of fibrosis and cellularity are importantdeterminants of likely response to treatment and prognosis.
Data on the HRCT features of (biopsy confirmed) desquamativeinterstitial pneumonitis (DIP) and non-specific interstitialpneumonitis (NSIP) are limited. Patchy areas of ground glassopacification are typically seen in DIP; there is a lower zonepredominance in the majority of patients but a subpleural distributionis documented in just over half. Ground glass opacificationis also a dominant CT finding in NSIP but, in general, the CTappearances are inconsistent.
