The Value of Dynamic Enhanced CT in Solitary Pulmonary Nodule

Objective To evaluate the degree of enhancement and patterns of dynamic time-density curves in the solitary pulmonary nodule and study its mechanism of the enhancement.Materials and Methods 40 patients of pulmonary nodules proved pathologically were performed with dynamic enhanced CT to analyze peak net nodule enhancement and time-attenuation curves. 20 histologic specimens were underwent after immuoperoxidase microvascular staining with antibody to CD34 antigen staining.Results Malignant nodules were enhanced (16～76 HU) significantly more than benign nodules (-6～46 HU,P0.01). With 15HU as the threshold, the sensitivity was 100% (27 of 27 malignant nodules), the specificity was 46% (6 of 13 benign nodules), the accuracy was 82.5% (33 of 40 nodules). The degree of enhancement was statistically significantly related to the amount of central microvascular staining (P=0.006).Conclusion Lung nodule enhancement less than 15HU at dynamic enhanced CT is strongly predictive of benignity. There are more central staining of microvessels in malignant nodules than benign nodules, so malignant nodules enhance significantly more than benign nodules. False-positive results mostly are caused by the inflammatory pseudotumor, analysis of its time-attenuation curve could help differentiate from the malignant nodule.