Solitary pulmonary nodules: Part II. Evaluation of the indeterminate nodule

Various strategies may be used to evaluate indeterminate solitary pulmonary nodules. Growth rate assessment is an important and cost-effective step in the evaluation of these nodules. Clinical features (eg, patient age, histo ry of prior malignancy, presenting symptoms, smoking history) can be useful in suggesting the diagnosis and aiding in management planning. Bayesian an alysis allows more precise determination of the probability of malignancy ( pCa). Decision analysis models suggest that the most cost-effective managem ent strategy depends on the pCa for a given nodule. At contrast material-en hanced computed tomography, nodular enhancement of less than 15 HU is stron gly predictive of a benign lesion, whereas enhancement of more than 20 HU t ypically indicates malignancy. At 2-[fluorine-18]fluoro-2-deoxy-D-glucose ( FDG) positron emission tomography, lesions with low FDG uptake are typicall y benign, whereas those with increased FDG uptake are typically malignant. Results of transthoracic needle aspiration biopsy influence management in a pproximately 50% of cases and, in indeterminate lesions with a pCa between 0.05 and 0.6, is the best initial diagnostic procedure. It is optimally use d in peripheral nodules and has been reported to establish a benign diagnos is in up to 91% of cases. Although there is no one correct management appro ach, the ability to distinguish benign from malignant solitary pulmonary le sions has improved with the use of these strategies.