Pulmonary nodules, found either incidentally or on lung cancer
screening, are common. Evaluating the benign or malignant nature of these nodules is costly in terms of patient risk and expense. The presence of both global and regional emphysema
has been linked to increased lung cancer
risk. We sought to determine whether the measurement of emphysema
directly adjacent to a lung nodule could inform the likelihood of a nodule being malignant.
Materials and Methods:
Within a population of Veterans at high risk for lung cancer
, 58 subjects with malignant nodules found on computerized tomographic chest scans were matched by lobe and nodule size to 58 controls. Lung densitometry was measured via determination of the low attenuation area percentage at −950 Hounsfield units (LAA950) and the Hounsfield unit (HU) value at which 15% of lung voxels have a lower lung density (Perc15), at predefined lung volumes that encompassed the nodule to evaluate both perinodular and regional lung fields. The association between measured lung density and malignancy was investigated using conditional logistic regression models, with densitometry measurements used as the primary predictor, adjusting for age alone, or age and computerized tomographic scan characteristics.
No significant differences in emphysema
measurements between malignant and benign nodules were identified at lung volumes encompassing both perinodular and regional emphysema
. Furthermore, emphysema
quantification remained stable across lung volumes within individuals.
In this study, quantifying the degree of perinodular or regional emphysema
did not offer any benefit in the risk stratification
of lung nodules.