Imaging: how to recognise idiopathic pulmonary fibrosis

Abstract

It is well known that high-resolution computed tomography (HRCT) is an essential component of the diagnostic pathway in idiopathic pulmonary fibrosis (IPF). Honeycombing, a common feature of IPF seen on HRCT, is crucial for an accurate diagnosis. Unfortunately, identification of honeycombing is not always straightforward, and there is some disagreement regarding its imaging features. It can be difficult to distinguish honeycombing from traction bronchiectasis and emphysema, although several imaging characteristics can be helpful. Recently, there has been an interest in expanding the use of HRCT beyond diagnosis for disease monitoring and prognostication, and several studies have provided valuable contributions in this regard. Traction bronchiectasis and the extent of fibrosis, for example, have been reported to be powerful prognostic predictors for mortality. Finally, considering the difficulties in diagnosis of "possible usual interstitial pneumonia", clinicians should always be aware that clinical factors must be considered together with HRCT in order to reach an accurate diagnosis and provide appropriate treatment.

Figure 1.

High-resolution computed tomography scan showing typical appearance of usual interstitial pneumonia.

Figure 2.

Computed tomography scan from a patient with emphysema, thus identification of honeycombing was rendered difficult.