LungRADS

Lung-RADS, short for Lung Imaging Reporting and Data System, is a quality assurance and reporting framework developed by the American College of Radiology to standardize the interpretation of low-dose CT scans used for lung cancer screening. It aims to reduce variability in radiology reports and help ensure appropriate follow-up for screen-detected nodules.

The system assigns a screening exam to a category on a scale from 0 to 4, with 0 indicating incomplete evaluation and higher numbers indicating increasing suspicion for malignancy. In many versions, category 1 denotes a negative study, category 2 indicates benign-appearing nodules, category 3 reflects probably benign nodules, and category 4 signals suspicion for cancer. Some versions subdivide category 4 (for example, 4A and 4B) to reflect differing levels of concern and urgency for diagnostic workup.

Management guidance is linked to the category. Negative or benign results typically lead to routine annual screening, while probably benign nodules suggest short-interval follow-up. Nodules categorized as suspicious for cancer generally prompt more immediate diagnostic actions, such as further imaging or tissue sampling. The exact recommended actions and imaging intervals depend on the Lung-RADS version in use and local protocol.

History and use indicate that Lung-RADS was introduced by the ACR in the early 2010s to standardize reporting for lung cancer screening programs, with broader adoption in the United States and integration into research and program guidelines. It is designed for screening populations and is not intended to replace diagnostic evaluation when cancer is suspected.

Limitations include reliance on radiologist interpretation, potential mismatches with non-screening CTs, and the fact that Lung-RADS is a guideline rather than a definitive diagnostic tool.