The Fleischner Criteria

Fleischner Criteria for the management of incidentally detected pulmonary nodules on CT scans

The Fleischner Criteria, provides standardized recommendations for the management of incidentally detected pulmonary nodules on CT scans.  The key word here is incidentally detected, this is not to be used for LUNG RADS screening low dose CT. Fleischner guidelines help radiologists and clinicians assess the risk of malignancy and determine appropriate follow-up intervals based on nodule size, appearance, and patient risk factors. Originally introduced in 2005 and updated in 2017, the criteria aim to reduce unnecessary testing while ensuring timely diagnosis of potentially malignant nodules.

One of the key strengths of the Fleischner Criteria is its risk-based approach. The guidelines distinguish between low-risk and high-risk patients, based on factors like age, smoking history, and cancer history. Nodules are further categorized by size (typically using a 6 mm and 8 mm threshold) and morphology (solid, subsolid, or part-solid). For example, a solitary solid nodule less than 6 mm in a low-risk patient generally requires no follow-up, while a larger or part-solid nodule may require serial imaging or even tissue sampling.

These recommendations provide a structured, evidence-based pathway that helps reduce variation in care. Knowing that a nodule <6 in a low risk patient which is purely solid or ground glass really needs no specific follow up is a key takeaway. By standardizing follow-up intervals and reducing over-surveillance of benign nodules, the Fleischner Criteria help limit patient anxiety, avoid unnecessary radiation exposure, and manage healthcare costs more effectively. Conversely, nodules with suspicious features or in high-risk patients are monitored more closely, increasing the chances of early detection of lung cancer.