To study CT findings of usual interstitial pneumonia (UIP). To study the differentiating features of UIP in idiopathic pulmonary fibrosis (IPF) and UIP in Connective tissue disorders (CTD).

Usual interstitial pneumonia (UIP) is a common type of interstitial lung disease which shows spatial inhomogeneity.It is morphological equivalent of idiopathic pulmonary fibrosis (IPF). Idiopathic pulmonary fibrosis is a type of interstitial fibrosing pneumonia which is chronic and progressive in nature. Classically all the cases of UIP have to be first evaluated for secondary causes like connective tissue disorders, asbestosis, radiation exposure or drug intake. When all the secondary causes are ruled out, then the diagnosis of idiopathic pulmonary fibrosis is made. Conventionally imaging features...

Imaging plays a very important role in the diagnosis of UIP as the correct diagnosis would preclude the need for lung biopsy which is an invasive procedure. Imaging features of UIP There is generalreduction in lung volumes(figure 1). Disease pathology is bilateral symmetrical havingapico-basal gradient(figure 2). The disease is concentrated maximum insubpleural regionwith peripheral predominance (figure 2). Initially there is interlobular and intralobular septal thickening appearing asreticular opacities(figure 3), when advanced leads onto formation of honeycombing (involving >5% of lung volume).Honeycombing(Figure 4) is defined as...

It is essential to differentiate UIP in CTD and UIP in IPF as the management and the prognosis of the two varies. The three signs described above should be carefully looked for, in every case of UIP.

A. Aggarwal; New Delhi/IN - nothing to disclose A. Sharma; Gurgaon/IN - nothing to disclose A. Malik; Delhi/IN - nothing to disclose G. Sindhwani; New Delhi/IN - nothing to disclose

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