- The smallest breakpoint is now 6 mm.
- The guidance table now separates into risk factors rather than nodule size and multiplicity of nodules.
- Distinction between solid and sub solid nodules.
- Guidelines should only be applied the age > than 35. Outside of this age range, follow-up should be tailored to the patient.
- For solid nodules, the minimum threshold size for routine follow-up has been increased, and fewer follow-up examinations are recommended for stable nodules.
- For subsolid nodules, a longer period is recommended before initial follow-up, and the total length of follow-up has been extended to 5 years.
- These guidelines apply to incidental nodules, which can be managed according to the specific recommendations.
- These guidelines do not apply to patients younger than 35 years, immunocompromised patients, or patients with cancer.
- For lung cancer screening, adherence to the existing American College of Radiology Lung CT Screening Reporting and Data System (Lung-RADS) guidelines is recommended.
The Fleischner Society Guidelines have been a godsend for the management of incidental pulmonary nodules. This area has plagued radiology and IMHO serves as a useful barometer for both radiologists and practices. If a practice uses arbitrary follow-up for pulmonary nodules rather than guidelines, in my experience, there are probably other failings.
More advanced practices not only include the recommendation and description of the nodules but also include the reference and optimally, the guideline table in the report to help the clinicians decide how to manage the patient since clinical information relevant to follow-up is usually not available to the radiologist (pertinent risk factors are frequently not given).
Source Ref: Guidelines for Management of Incidental Pulmonary Nodules Detected on CT Images: From the Fleischner Society 2017, Heber MacMahon et al., Radiology 2017 284:1, 228-243.
This is a juicy article with lots of nuggets:
Finally! Some data driven guidance on subpleural/intrapulmonary nodes. Yay!
Perifissural nodule is a term used to describe small solid nodules that are commonly seen on CT images adjacent to pleural fissures and that are thought to represent intrapulmonary lymph nodes. Similar nodules can occur in other locations, usually adjacent to a pleural surface. Typically, these are triangular or oval on transverse images, and they have a flat or lentiform configuration in sagittal or coronal reconstructions and a fine linear septal extension to the pleura. When small nodules have a perifissural or other juxtapleural location and a morphology consistent with an intrapulmonary lymph node, follow-up CT is not recommended, even if the average dimension exceeds 6 mm. In one study of patients in the NELSON Lung Cancer Screening Trial, 20% of nodules were classified as perifissural, and 16% of these grew during the study; however, none were malignant (94). However, perifissural or juxtapleural location does not in itself reliably indicate benignancy, and the specific nodule morphology must be considered (95, 96). A spiculated border, displacement of the adjacent fissure, or a history of cancer increase the possibility of malignancy, and a follow-up examination in 6–12 months should be considered in these patients.
Incidentally Detected Lung Nodules on Incomplete Thoracic CT Scans
Lung nodules are commonly encountered in the portions of the lungs that are included on CT scans of the neck, heart, and abdomen, and the question often arises as to whether a complete thoracic CT examination should be performed in such instances.
For most small nodules (<6 mm), we do not recommend any further investigation on the basis of the estimated low risk of malignancy (6,7). For intermediate-size (6–8-mm) nodules, we recommend follow-up CT of the complete chest after an appropriate interval (3–12 months depending on clinical risk) to confirm stability and to evaluate additional findings. If nodule stability can be demonstrated on the basis of retrospective comparison with a previous study, that may suffice. In the case of a large or very suspicious nodule, we recommend proceeding with a complete thoracic CT examination for further evaluation.
Partial Thoracic CT Scans for Nodule Follow-up
We do not recommend use of partial thoracic scans for practical reasons, including the need for a technologist or radiologist to determine the appropriate range of the scan from a scout image and the possible detection of unanticipated abnormal findings that would require complete examination of the thorax to properly evaluate.
Some degree of pleural and subpleural apical scarring is extremely common, and these scars may have a nodular appearance, especially when viewed on transverse images. Certain features are suggestive of a scar, including a pleural-based configuration, an elongated shape, straight or concave margins, and the presence of similar adjacent opacities. Review on coronal or sagittal reconstructed images can be helpful in the characterization of such findings. Similar considerations apply to subpleural opacities in other locations, including the costophrenic angles, where focal scarring is also common.