Cohen et al [35] retrospectively studied the differences in semiautomated attenuation measurements on unenhanced and enhanced CTs of 53 adenocarcinomas presenting as part-solid nodules. The study showed that most parameters were significantly increased on enhanced CT, including longest transverse diameter of the whole nodule, the solid component, nodule volume and mass, solid component volume and mass, and nodule attenuation. The only parameter that was not significantly elevated was the solid component attenuation, highlighting that caution must be taken when comparing part-solid nodules obtained on studies with and without IV contrast. The role of FDG-PET/CT in the differentiation of benign from malignant nodules has been extensively studied and relies on measuring glucose metabolism, which is typically elevated on malignant lesions. Reported sensitivities and specificities range from 88% to 96% and 77% to 88%, respectively [1,5,32]. Given PET limited spatial resolution, its use in the management of incidental pulmonary nodules is suggested for nodules >0.8 cm [2,9,40]. Nodule size (generally >0.8 cm), nodule attenuation, selected patient cohorts, how a malignant nodule is defined, Incidentally Detected Indeterminate Pulmonary Nodule and technical factors vary by study and should be considered when making conclusions about reported sensitivities and specificities. PET/CT and contrast-enhanced CT have been compared for the evaluation of solitary pulmonary nodules on small series, with results favoring PET/CT over dynamic CT. Christensen et al [36] showed sensitivities and specificities of 96% and 76% for PET/CT versus 100% and 29% for dynamic CT. Yi et al showed sensitivity, specificity, and accuracy of 96%, 88%, and 93% for PET/CT versus 81%, 93%, and 85% for dynamic CT, respectively [5,32]. False-negative results on PET/CT go beyond small nodule size (<0.8 cm).
Incidentally Detected Indeterminate Pulmonary Nodule PCAs. Cohen et al [35] retrospectively studied the differences in semiautomated attenuation measurements on unenhanced and enhanced CTs of 53 adenocarcinomas presenting as part-solid nodules. The study showed that most parameters were significantly increased on enhanced CT, including longest transverse diameter of the whole nodule, the solid component, nodule volume and mass, solid component volume and mass, and nodule attenuation. The only parameter that was not significantly elevated was the solid component attenuation, highlighting that caution must be taken when comparing part-solid nodules obtained on studies with and without IV contrast. The role of FDG-PET/CT in the differentiation of benign from malignant nodules has been extensively studied and relies on measuring glucose metabolism, which is typically elevated on malignant lesions. Reported sensitivities and specificities range from 88% to 96% and 77% to 88%, respectively [1,5,32]. Given PET limited spatial resolution, its use in the management of incidental pulmonary nodules is suggested for nodules >0.8 cm [2,9,40]. Nodule size (generally >0.8 cm), nodule attenuation, selected patient cohorts, how a malignant nodule is defined, Incidentally Detected Indeterminate Pulmonary Nodule and technical factors vary by study and should be considered when making conclusions about reported sensitivities and specificities. PET/CT and contrast-enhanced CT have been compared for the evaluation of solitary pulmonary nodules on small series, with results favoring PET/CT over dynamic CT. Christensen et al [36] showed sensitivities and specificities of 96% and 76% for PET/CT versus 100% and 29% for dynamic CT. Yi et al showed sensitivity, specificity, and accuracy of 96%, 88%, and 93% for PET/CT versus 81%, 93%, and 85% for dynamic CT, respectively [5,32]. False-negative results on PET/CT go beyond small nodule size (<0.8 cm).