Incidental multiple pulmonary nodules evaluation

CT: computed tomography.
* Nodule is a well-defined opacity completely surrounded by lung parenchyma measuring <30 mm in longest dimension.
¶ For multiple nodules, choice of solid versus subsolid is based on the largest or the predominant pattern.
Δ Chest CT should be performed without contrast as contiguous thin (ie, 1 mm) images on a helical scanner using low radiation dose techniques.
◊ Growth is defined as >2 mm increase in overall size. For subsolid nodules, growth can also be an increase in attenuation or appearance or enlargement of a solid component.
§ If the chest CT reveals findings relevant to nodule diagnosis (eg, other nodules or masses, mediastinal lymphadenopathy, or findings of pulmonary inflammation or infection), subsequent workup should be based on these findings.
¥ Suspicious nodule is the one with the largest or, for part solid nodules, the one with the most solid component.
‡ Nodule size is defined as the average of long and short axes in axial cross-section.
† Likelihood of malignancy assessed either clinically or by quantitative predictive models.
** Chest CT follow-up at 12 months is optional in patients who are high or intermediate risk for malignancy.
¶¶ Timing of chest CT is relative to the date of the initial nodule detection.
ΔΔ Optional chest CT at 18 to 24 months if stability of nodules is equivocal.
◊◊ If solid portion of nodule is >8 mm and if clinical suspicion for malignancy is high, this CT can be deferred and the clinician may proceed to the next step with the assumption of a persistent non-enlarging, part-solid nodule.
§§ If nodule is persistent but not growing and the solid portion is >8 mm, FDG PET/CT is an option. FDG-avid nodules proceed to tissue sampling. FDG non-avid nodules are triaged to annual CT surveillance.