Lung nodule enhancement at CT: prospective findings.

PURPOSE

To determine if lung nodule enhancement measured with computed tomography (CT) is directly related to the likelihood of malignancy and to nodule vascularity.

MATERIALS AND METHODS

Radiologically indeterminate 7-30-mm pulmonary nodules were studied in 107 patients with malignant neoplasms (n = 52), granulomas (n = 51), and benign neoplasms (n = 4). Attenuation was recorded from serial thin-section CT scans before and after injection of contrast material. Twenty-four histologic specimens were graded after immunoperoxidase vascular staining with antibody to factor VIII-associated antigen.

RESULTS

Malignant neoplasms were enhanced (median, 46.5 HU; range, 11-110 HU) statistically significantly more than granulomas and benign neoplasms (median, 8 HU; range, -10 to 94 HU) (P < .001). With 20 HU as the threshold for a positive test result, the sensitivity was 98%, specificity was 73%, and accuracy was 85% (prevalence of malignancy, 49% ¿52 of 107 nodules]). The degree of enhancement was statistically significantly related to the amount of central vascular staining (P < .001).

CONCLUSION

Enhancement appears to be an indicator of malignancy and vascularity. These prospective findings corroborate previously reported results.