CT scans are used to diagnose, track, and screen for a variety of diseases. Even before the National Lung Screening Trial research team proved that an annual CT scan could reduce lung cancer mortality, physicians were ordering 62 million scans per year. At the same time, advances in technology have improved power and resolution. The CT scan has changed the way that healthcare is practiced, and that change has created challenges and opportunities. We're now experiencing a modern pandemic of incidental findings. It falls to the clinician to decide when the dreaded "incidentaloma" is clinically relevant.
Pulmonologists are adept at managing pulmonary nodules found on scans performed for other reasons. Multiple risk-stratification models exist and guidelines provide algorithms that are easy to follow. Radiologists generally reference these guidelines in their reports and instruct the clinician on how to proceed. A less common but still prevalent incidental finding in the pulmonary parenchyma is an interstitial lung abnormality (ILA).
What is an ILA and how is it defined? Well, it's tricky. A position paper from the Fleischner Society outlines specific radiographic findings that are consistent with an ILA: honeycombing, traction bronchiectasisparenchymal distortions, and reticular abnormalities that take up more than 5% of a particular lung zone.
