Radiographic assessment of small lung nodules: what can we do and what information does it give us?

Abstract

The evaluation of small pulmonary nodules is a common and challenging clinical scenario often requiring a multi-disciplinary approach to optimize patient care. Radiographic assessment of pulmonary nodules is an important part of the determination of whether a nodule is malignant or benign which then translates into an intervention or a management strategy. A multimodality radiological approach or longitudinal follow up may be needed based on a combination of the clinical and imaging features at initial presentation. In this article, we illustrate the role of anatomical and functional radiological techniques [chest radiography, computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography/computed tomography (PET/CT)] in the assessment and characterization of small pulmonary nodules, with an emphasis on chest CT, the workhorse of pulmonary imaging. This discussion is framed in the context of how imaging fits into current international guidelines on pulmonary nodule assessment, with an emphasis on both the Fleischner society and British Thoracic Society (BTS) guidelines, including the application of nodule risk prediction scores. Emerging applications including radiomics, machine learning and artificial intelligence (AI) in assessment and characterization of pulmonary nodules and role of these advanced techniques in the management of pulmonary nodules in the future are also illustrated.