Dynamic CT And Tumor Angiogenesis In Lung Nodules: Radiologic-pathologic Correlation

The Solitary Pulmonary Nodules (SPNs) is one of the most common findings on chest radiographs. The primary goal of the radiological evaluation of a SPNs is to differentiate between benign and malignant disease. To date, characterization of SPNs by CT has been based on nodules morphology and nodules attenuation. However, most uncalcified and nonfat-containing SPNs cannot be characterized on the basis of this evaluation. Nowadays, both enhancement and morphologic analyses are important and should be performed together hi the study of SPNs with dynamic CT. Among the new methods used for noninvasive tissue characterization, the assessment of contrast enhancement kinetics has received increased attention. The blood supply of malignant pulmonary nodules is qualitatively and quantitatively different from that of benign nodules. The continuous growth of a tumor beyond a critical size is dependent on the development of new blood vessels, which not only supply nutrition for further growth of the tumor but also serve as a route for systemic metastasis. Angiogenesis is a complex process, critical to the growth and metastasis of malignant tumors. Angiogenesis is mediated by factors released by tumors and/or tumor-associated inflammatory cells. Vascular endothelial growth factor (VEGF) is known as a vascular permeability factor and plays an important role in tumor angiogenesis. Angiopoietin is also an important vascular growth factor. Literature reported that the peak attenuation of tumor reflects intratumoral microvessel densities (MVDs) on dynamic CT. In this study, we investigated the VEGF- and Ang-related neovascularization, evaluated the MVD in SPNs, and study on the correlation between the dynamic CT and angiogenesis in pulmonary nodules.Part I Solitary Pulmonary Nodules: Evaluation with Dynamic Contrast-Enhanced CTPurpose: To evaluate the SPN with standard dynamic contrast-enhanced CT technique, to analyze the value of dynamic CT in differentiation malignant from benign dodules, and to choose the optimal parameter of dynamic CT, estabilish the diagnositic enteria of dinerentiation between them.Materials and Methods: Seventy-seven patients with SPN met our criteria. Among the 77 patients, the diagnosis was malignant in 52(adenocarcinoma in 23 patients, squamous cell carcinoma in 21 patients, adeno-squamous cell carcinoma in 4 patients, small cell carcinoma in one patient, metastatic tumor from breast cancer and colon cancer in two patients, malignant fibrous histio-cytoma in one patient) and benign in 25 patients (including submesothelial fibroma in one patient, hamartoma in two patients, tuberculoma in six patients, inflammatory pseudotumors and inactive inflammatory nodules in 10 patients, active inflammatory nodules in six patients). All these patients were divided into three groups: malignant group (n=52); benign group A (n=19); benign group B (n=6), which comprised the patients with active inflammatory nodules. Group A and group B were combined as benign group. All patients were examined with 3~5mm-collimation prec' ntrast and dynamic contrast-enhanced CT at 20s, 29s, 38s, 47s, 56s, 65s, 74s, 83s, 92s, 101s, 110s, 119s, 150s, 180s, 240s, 300s, 360s, 420s, 480s after onset of injection (2ml/s; 1.5ml contrast material per kilogram of body weight). Enhancement patterns(EP), peak height(PH), contrast enhancement ratio(CER), peak time(PT), time-attenuation curve(TAC) and absolute contrast-enhancemend CT value were analyzed.Result: Precontrast attenuation of the inflammatory nodules was lower than that of the malignant group and benign group A, but the difference in attenuation did not reach statistical significance. The contrast material enhancement patterns of the SPNs were extremely complex. Homogeneous and heterogeneous enhancement were the main pattern in the malignant group. Homogeneous and heterogeneous enhancement pattern were observed in the most cases of the benign group. PH of the malignant group nodules and inflammatory nodules were significantly higher than that of the benign group A (p<0.