NSIP is a chronic, fibrotic interstitial pneumonia, which carries a better prognosis than UIP.34,35 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

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Idiopathic Pulmonary Fibrosis (an Update) and Progressive Pulmonary Fibrosis in Adults: An Official ATS/ERS/JRS/ALAT Clinical Practice Guideline

Reference

3. Gotway MB, Freemer MM, King TE, Jr. Challenges in pulmonary fibrosis. 1: Use of high resolution CT scanning of the lung for the evaluation of patients with idiopathic interstitial pneumonias. Thorax. 2007;62:546-553.

34. Travis WD, Costabel U, Hansell DM, et al. An official American Thoracic Society/European Respiratory Society statement: update of the international multidisciplinary classification of the idiopathic interstitial pneumonias. Am J Respir Crit Care Med. 2013;188:733-748.

35. Koelsch TL, Chung JH, Lynch DA. Radiologic evaluation of idiopathic interstitial pneumonias. Clin Chest Med. 2015;36:269-282.

36. Mueller-Mang C, Grosse C, Schmid K, Stiebellehner L, Bankier AA. What every radiologist should know about idiopathic interstitial pneumonias. Radiographics. 2007;27:595-615.