Opportunistic Screening on Chest CT, From the AJR Special Series on Screening

The increase in chest CT volumes affords radiologists the opportunity to systematically assess imaging biomarkers including coronary and thoracic arterial calcification, emphysema, airway dysanapsis, adipose tissue in various compartments, skeletal muscle (in terms of both quantity and quality), and vertebral body bone attenuation (as a measure of bone mineral density), extending from the T1 through T12 vertebral body levels (1). These biomarkers represent a spectrum of disease-induced changes or increases in risk for developing disease. This Special Series review provides an overview of these established and emerging imaging biomarkers on chest CT scans, aiming to serve as a reference for practicing radiologists. We discuss the imaging biomarkers' importance for patient care, highlight recent developments, present approaches for interpretation and integration into clinical workflows with attention to the role of reference values, consider challenges in serial assessment resulting from variations in technical parameters, describe the biomarkers' incorporation into societal guidelines, and summarize FDA-approved AI tools to aid evaluation.