Interstitial lung abnormalities: prognostic stratification of subtle radiological findings.

PURPOSE OF REVIEW: The purpose of this review is to provide the radiological description of interstitial lung abnormalities (ILA) as an increasingly reported entity on high-resolution computed tomography (HRCT), and to discuss their prospective interpretation.

RECENT FINDINGS: Elementary findings consistent with ILA are described on HRCT, yet the diagnostic confidence for the interpretation of these subtle features might be challenging and further hampered by interobserver variability. Quantitative analysis is expected to provide standardized and reproducible description of ILA. There is affinity between ILA morphology and histopathological pattern, either fibrosis or atypical adenomatous hyperplasia. Beyond radiology, there are predictors of risk of ILA, such as: age, smoking habit, circulating biomarkers, and genetic sequencing. ILA with fibrotic morphology show prognostic impact including progression to interstitial lung disease, mortality from respiratory disease, and all-cause mortality. The association between ILA and susceptibility to lung damage further includes the interlacing connection between interstitial findings and lung cancer, both as a risk factor for diagnosis and as a predictor of survival.

SUMMARY: ILA are a (minor) finding on HRCT and they should be reported by radiologists for optimal management within the specific clinic-functional scenario. ILA encompass a number of semiological characteristics associated with either fibrotic or nonfibrotic disease.