Figure 3. Traditional and future algorithms for the diagnosis of interstitial lung disease.

(A) Traditional approach to diagnosis of interstitial lung disease that includes high-resolution CT to identify the pattern of usual interstitial pneumonia. Surgical lung biopsy is recommended in patients with a high-resolution CT pattern of possible usual interstitial pneumoniaor inconsistent with usual interstitial pneumonia in an appropriate clinical setting. Multidisciplinary diagnosis is recommended as a key feature of the diagnostic pathway. Adapted from Raghu and colleagues.²⁰ (B) Modified recommendation in which high-resolution CT retains a crucial initial diagnostic role. In cases in which high-resolution CT is diagnostic of an alternative process, a diagnosis is assured. As systemic or lung-specific biological markers evolve, these could become key diagnostic or prognostic markers that will supplement clinical and imaging evaluation, and potentially obviate the need for surgical lung biopsy. HRCT=high-resolution CT. ILD=interstitial lung disease. IPF=idiopathic pulmonary fibrosis. MDD=multidisciplinary diagnosis. UIP=usual interstitial pneumonia.