Therapeutic relevance of HRCT findings from a pneumological viewpoint

Abstract

The high-resolution computed tomography (HRCT) technique is an essential component in diagnosing interstitial lung disease (ILD) as it provides important and specialized information and a much greater accuracy than chest X-rays. It contributes to a narrowing down of the differential diagnoses and is also important for planning further invasive investigations, e.g. bronchoscopy, bronchoalveolar lavage, transbronchial lung biopsy and surgical lung biopsy, if needed. An accurate diagnosis of ILD is based on a multidisciplinary discussion involving pulmonologists, radiologists and pathologists experienced in the diagnosis of ILD.The therapy approaches of five different entities of ILD are shown as examples. In hypersensitivity pneumonitis the mainstay of treatment is complete avoidance of exposure to the provoking antigen. In cryptogenic organizing pneumonia most patients recover with corticosteroid therapy with prednisolone over a period of 6 months to 1 year. In cases of sarcoidosis therapy depends on organ involvement and functional impairment but there is no durable benefit to routine treatment of patients with acute pulmonary sarcoidosis, even among those with stage II or III chest radiographs. In general, patients with severe or progressive disease will require treatment.In idiopathic pulmonary fibrosis (IPF) a confident radiological diagnosis of definitive usual interstitial pneumonia (UIP) obviates the need for surgical lung biopsy. Other etiologies of a HRCT pattern of UIP, such as domestic and occupational environmental exposure, connective tissue disease and drug toxicity must be ruled out. In IPF antifibrotic therapy with pirfenidone (approval since 2011) or the triple tyrosine kinase inhibitor nintendanib (pending approval in 2015) can reduce disease progression but therapy with acetylcysteine alone or in combination with prednisolone and azathioprine failed to meet efficacy endpoints. In the management of scleroderma associated ILD rapid semiquantitative evaluation of the extent of the disease on HRCT > 20% is useful for identifying patients who require treatment.