ABSTRACT
This chapter reviews evaluation strategies and recent advances in imaging that can improve the accuracy of differentiating benign and malignant solitary pulmonary opacities. A solitary pulmonary nodule is defined as “a round opacity, at least moderately well-marginated and no greater than 3 cm in maximum diameter”. The overall clinical impact of this finding in nodule evaluation is small, as hamartomas constitute a very small percentage of solitary pulmonary opacities. Perfusion and metabolism of malignant pulmonary nodules is qualitatively and quantitatively different from that of benign nodules. Positron emission tomography can be used as an additional study to evaluate a solitary pulmonary opacity detected radiologically or as an alternative to contrast-enhanced computed tomography (CT) to differentiate benign from malignant nodules. Noninvasive image-based assessment and management of the opacities has evolved in large part due to data extrapolated from ongoing screening studies and from thin-slice helical CT scans studies examining the morphologic features of nodules.
