Is HRCT the best way to diagnose idiopathic interstitial fibrosis?

High-resolution computed tomography (HRCT) has been the major advance in the diagnosis of idiopathic interstitial pneumonias in the last two decades. In diffuse lung diseases, HRCT now has a central role in routine diagnostic evaluation, and a major impact on the utility of other diagnostic tests, especially bronchoalveolar lavage and surgical lung biopsy.

Numerous published studies have evaluated the accuracy of HRCT. The clinical information was not always utilized to generate a noninvasive diagnosis, however. Despite failure to identify idiopathic pulmonary fibrosis on HRCT in a significant minority of cases, given compatible clinical data, characteristic HRCT appearances justify noninvasive diagnosis in most patients. The limitations of the published studies highlight importance of integrating HRCT data with baseline clinical information and, in selected cases, histopathologic findings.

When HRCT and clinical findings are both typical of an individual diffuse lung disease, i.e. 'pathognomonic', it is generally appropriate to institute management based on a confident noninvasive diagnosis. When clinical and HRCT data are divergent, or when HRCT features are 'indeterminate', however, histologic evaluation continues to play an essential role. Integration of histology with radiologic and clinical data is the best way to formulate the final diagnosis in these cases.