Using the First Pass Dynamic Contrast Enhanced Technique with 16-slice Spiral CT to Differentiate Benign from Malignant Solitary Pulmonary Nodules and to Study the Basis of its Molecular Biology

Objective:To evaluate the efficacy of the first pass dynamic enhanced technique with 16-slice spiral CT for the differentiation of benign from malignant solitary pulmonary nodules(SPNs)and to correlate the imaging findings with microvessel density(MVD)of tumor as well as to illustrate the basis of molecular biology in the differential diagnosis.Methods:72 patients with SPNs underwent first pass dynamic enhanced technique with multi-slice spiral computed tomography(MSCT).61 patients were included into the study.The peak height(PH)of the first pass was measured.The first pass PH of 40 SPNs were compared with their specimen for microvessel densities(MVDs)by immunohistochemistry with SP technique.The relationship was assessed by means of linear regression analysis.Results:The mean MVD(32.821±19.459/0.723mm2)and the first pass PH(22.864±13.514)HU of malignant SPNs were significantly higher than those of benign ones(14.333±10.577/0.723mm2 and 10.912±5.452HU)respectively(P0.01).Each first pass PH of these 40 SPNs was correlated positively with MVDs(r=0.821).Taken 15HU for the first pass PH as the cutoff value in the differentiation for malignant and benign SPNs,the sensitivity,specificity,accuracy,positive predictive value,negative predictive value were 87.5%、72.41%、77.78%、84.00%、80.33% respectively.Conclusion:The first pass dynamic contrast enhanced CT technique proved to be useful in the differentiation of benign from malignant SPNs.The MVDs of the SPNs could be evaluated accurately by the PH of the first pass,which is the molecular biology basis of the first pass dynamic enhanced MSCT in the differential diagnosis.