Fibrosing Interstitial Lung Disease. A Practical High-Resolution Computed Tomography–based Approach to Diagnosis and Management and a Review of the Literature

Establishing the etiology of fibrosing interstitial lung disease (FILD) remains a clinical challenge. This is because many disorders resulting in lung fibrosis may be similar in their initial clinical and radiographic appearances. High-resolution computed tomography (HRCT) studies are now almost always obtained for patients who present with otherwise nonspecific clinical symptoms and chest radiographic findings. In the majority of cases presenting with FILD, differential diagnosis typically requires differentiating among three most commonly encountered clinical entities: idiopathic pulmonary fibrosis with usual interstitial pneumonia, nonspecific interstitial pneumonia, and chronic hypersensitivity pneumonitis. As a consequence, the development of a simplified diagnostic algorithmic approach initially focusing on the interpretation of HRCT findings may prove of considerable value provided thorough familiarity with optimal HRCT techniques and methods of interpretation. For this purpose, in patients with FILD in whom an underlying etiology is not initially apparent, the recently proposed American Thoracic Society/European Respiratory Society/Japanese Respiratory Society/Latin American Thoracic Association guidelines for the diagnosis of IPF have been modified to create a straightforward, clinically practicable algorithmic approach to clinical management based on the initial interpretation and classification of HRCT findings.