The Application Of CT Perfusion Imaging In Solid Pulmonary Nodules

PURPOSETo calculate the CT perfusion parameters and generate time-density curves (TDC) of solitary pulmonary nodules(SPNs). Correlate the CT perfusion parameters of SPNs with standardized uptake values (SUV) derived from ¹⁸F-FDG PET and microvessel density (MVD). To determine the validity of CT perfusion in assessing tumor angiogenic activity of pulmonary carcinoma. To investigate the correlation between the CT perfusion parameters and the morphologic changes of SPNs, and assess the value of CT perfusion combining with morphologic changes of SPNs in the diagnosis of pulmonary malignant nodules.MATERALS AND METHODS73 patients (mean age 55.5, 26 females) with solitary pulmonary nodules underwent CT perfusion imaging after intravenous injection of 40 mL of contrast medium. Blood flow (BF, ml/100g/min), blood volume (BV, ml/100g), mean transmit time (MTT, s) and permeability surface area product (PS, ml/lOOg/min) were analyzed. SUV of PET was calculated in 14 patients. The CD34 immunohistochemical staining was used for tumor microvessel counting in 50 patients. CT Perfusion parameters of pulmonary carcinoma were correlatively studied with SUV and tumor MVD. The morphologic features(including lobulation, spiculation, vessel convergency, pleural indentation, bubblelike and air bronchogram, occlusion change distal to the lesion) were studied in 59 SPNs. Analyzed the correlation between morphologic changes and the CT perfusion parameters and MVD. The SPNs presented more than 3 signs were diagnosed as malignancy. Determine the sensitivity, specificity, accuracy, positive predict value and negative predictvalue. RESULTS1 The TDC had 3 types in malignant nodules and 4 types in benign nodules.2 MTT of malignant nodules was lower than that of benign nodules (6.75 and 15.35, respectively); PS was higher (34.52 and 22.82, respectively).3 BF, BV and PS of squamous cell carcinoma were 70.34 ^ 8.40 and 29.13, respectively, which was lower than that of adenocarcinoma (114.76, 9.51 and 41.75).4 When MTT^7s was selected as the cut-off value for malignant lesion, the sensitivity was 68.97%, specificity was 66.67%, accuracy was 68.49%, positive predict value was 88.89%, negative predict value was 35.71%. When PS^20 was selected as the cut-off value for malignant lesion, the sensitivity was 86.21%, specificity was 53.33%, accuracy was 79.45%, positive predict value was 87.72%, negative predict value was 50.0%5 There was positive correlation between BF and SUV (r=0.727, p<0.05) as well as MVD (r=0.543, p<0.05). Both BV and PS showed no statistically significant correlation with SUV, but they all showed positive correlation with MVD(r=0.375 and 0.346 respectively, p<0.05). Negative correlation was demonstrated between MTT and SUV (r=-0.033) as well as tumor MVD (r=-0.043), but the correlation was of no statistical significance. Positive correlation was demonstrated between tumor MVD and SUV (r=0.565, p<0.05).6 The demonstration of lobulation, vessel convergency and pleural indentation was improved on MPR compared with in axial image. Lobulation, vessel convergency, pleural indentation, bubblelike and air bronchogram, occlusion changes distal to the lesion in malignant SPNs were more common than in benign SPNs.7 The morphologic features of peripheral lung cancer were closely...