HRCT in ILD good review

The American Thoracic Society-European Respiratory Society classification of idiopathic interstitial pneumonias (IIPs), published in 2002, defines the morphologic patterns on which clinical-radiologic-pathologic diagnosis of IIPs is based. IIPs include seven entities: idiopathic pulmonary fibrosis, which is characterized by the morphologic pattern of usual interstitial pneumonia (UIP); nonspecific interstitial pneumonia (NSIP); cryptogenic organizing pneumonia (COP); respiratory bronchiolitis-associated interstitial lung disease (RB-ILD); desquamative interstitial pneumonia (DIP); lymphoid interstitial pneumonia (LIP); and acute interstitial pneumonia (AIP)...

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...

Before the advent of high-resolution computed tomography (HRCT), the role of imaging, chest radiography in particular, in the management of patients with interstitial lung disease was limited. In the past 25 years, this has radically changed. HRCT has transformed the diagnostic landscape by providing detailed cross-sectional imaging of the lungs, which permit ready identification of a variety of different interstitial lung diseases. Although the position of HRCT as the dominant imaging technique for interstitial lung disease has remained unchallenged since its introduction in the late 1980s, the roles assumed by HRCT have undergone a steady evolution...