Resolving small pulmonary nodules: CT features

Area of Science:

• Radiology
• Pulmonary Medicine
• Medical Imaging

Background:

• Pulmonary nodules are common findings on low-dose CT screening for lung cancer.
• Characterizing resolving pulmonary nodules is crucial for accurate diagnosis and management.
• Identifying specific CT morphologic features can aid in the initial classification of these nodules.

Purpose of the Study:

• To analyze the CT morphology of resolving pulmonary nodules over time.
• To identify morphologic features that are helpful in the initial classification of resolving pulmonary nodules.
• To correlate CT imaging characteristics with the resolution patterns of pulmonary nodules.

Main Methods:

• Retrospective review of CT imaging characteristics of 133 consecutive resolving pulmonary nodules in 56 subjects from a lung cancer screening trial.
• Consensus review by two readers to assess nodule size, location, and morphologic features (solid, well-defined, non-lobulated).
• Analysis of nodule resolution time, categorizing into complete and incomplete resolution.

Main Results:

• Resolving pulmonary nodules were predominantly small (<=10 mm), peripherally located, solid, well-defined, and non-lobulated.
• Nodule size distribution: <=5 mm (53%), 6-10 mm (39%), >10 mm (8%).
• Eighty percent of nodules resolved completely within a mean of 492 days; 20% showed incomplete resolution.

Conclusions:

• Resolving pulmonary nodules typically exhibit specific CT morphologic features: small size, peripheral location, solid composition, well-defined margins, and non-lobulated shape.
• These characteristics can assist in the initial classification of resolving pulmonary nodules detected on low-dose CT.
• Understanding the imaging features and resolution patterns of these nodules is important for clinical decision-making in lung cancer screening.