Type:
Educational Exhibit
Keywords:
Lung, CT-High Resolution, Diagnostic procedure, Education, Education and training
Authors:
M. Mangi, C. Chong, W. Lim
DOI:
10.26044/ranzcr2022/R-0041
Background
Insterstitial lung abnormality (ILA) is a relatively new term, defined as the presence of nondependent abnormalities affecting 5% or more of a lung zone seen on computed tomography (CT) in cases where interstitial lung disease (ILD) is not suspected [1,2]. ILA has a prevalence of up to 9% in smokers and 7% in non-smokers, and is associated with increasing age, inhalational exposures, and genetics [1]. ILA is clinically significant as it correlates with higher all-cause mortality and can progress to ILD [1]. Over 20% of ILA progress within 2 years, and about 50% within 5 years [2].
The important distinction between ILA and ILD is that ILA is a radiological finding, whilst ILD is a diagnosis that is only made after correlation with other clinical information [2]. ILD should be suspected based on the presence of characteristic clinical symptoms and signs such as clubbing, exposure history, pulmonary function testing (PFT) and serological testing for the exclusion of connective tissue diseases.