HRCT pattern | Surgical lung biopsy pattern# (when performed) | Diagnosis of IPF?¶ |
UIP | UIP | Yes |
Probable UIP | Yes | |
Possible UIP | Yes | |
Nonclassifiable fibrosis+ | Yes | |
Not UIP | No | |
Possible UIP | UIP | Yes |
Probable UIP | Yes | |
Possible UIP | Probable§ | |
Nonclassifiable fibrosis | Probable§ | |
Inconsistent with UIP | UIP | Possible§ |
Probable UIP | No | |
Possible UIP | No | |
Nonclassifiable fibrosis | No | |
Not UIP | No |
Certain combinations of high-resolution computed tomography (HRCT) and surgical lung biopsy patterns correspond with a diagnosis of idiopathic pulmonary fibrosis (IPF) (a yes in the far right column). For example, the combination of usual interstitial pneumonia (UIP) HRCT and probable UIP or possible UIP or nonclassifiable fibrosis patterns on surgical lung biopsy equals a diagnosis of IPF; the combination of UIP HRCT and not UIP surgical lung biopsy pattern does not make the diagnosis of IPF. #: patterns are as described in table 1. ¶: the accuracy of the diagnosis of IPF increases with multidisciplinary team (MDT) discussion. This is particularly relevant in cases in which the radiological and histopathological patterns are discordant (e.g. HRCT is inconsistent with UIP and histopathology is UIP). There are data to suggest that the accuracy of diagnosis is improved with MDT discussion among interstitial lung disease (ILD) experts compared with clinician specialists in the community setting [13]; timely referral to ILD experts is encouraged. +: some biopsies may reveal a pattern of fibrosis that does not meet the criteria for UIP pattern and the other idiopathic interstitial pneumonias [19]. These biopsies may be termed “nonclassifiable fibrosis.” §: MDT discussion should include discussions of the potential for sampling error and a re-evaluation of adequacy of the HRCT technique. In cases with an “inconsistent with UIP” HRCT pattern and a “UIP” surgical lung biopsy pattern, the possibility of a diagnosis of IPF still exists and clarification by MDT discussion among ILD experts is indicated. Reproduced and modified from [3] with permission from the publisher.