Nonspecific Interstitial Pneumonia

NSIP is a chronic, fibrotic interstitial pneumonia, which carries a better prognosis than UIP.³⁴³⁵ Of the idiopathic interstitial pneumonias, NSIP is the most difficult to distinguish from UIP.³ NSIP often occurs secondary to a known condition such as connective tissue disease, hypersensitivity pneumonitis, or drug toxicity.³⁵ The predominant features associated with NSIP on HRCT are ground glass opacity and reticulation with a peribronchovascular distribution.³⁶

Here we have another set of images from a patient with NSIP. On the coronal cut, diffuse ground glass opacity is seen predominantly in the lower lobes, with areas of traction on the airways, with no evidence of significant subpleural disease, honeycomb change, or traction bronchiectasis. On the axial cut, reticular architectural distortion is seen deep in the airways with some traction bronchiectasis. In addition to ground glass, there are some focal areas suggesting early fibrosis. The combination of diffuse ground glass with a central-to-peripheral distribution is typical for NSIP.³⁶