| Part 1 The solitary pulmonary nodule (SPN) is one of the most common findings of the lung, but Its diagnosis is still a challenge in thoracic radiology. Based on the morphologic features and characteristic calcification, computed tomography (CT) can make definite diagnosis of most of the SPNs, but difficulties still exist in some SPNs, the percentage of unnecessarily resected benign SPNs is as high as 30%. Swensen, Yamashita Zhang et al demonstrated the difference of blood supply and composition between benign and malignant nodules with dynamic CT enhancement, they all found that malignant nodules enhanced significantly more than benign nodules and considered the maximum attenuation of 20-60 HU to be a strong predictor of malignancy. These provide new proof for differentiating SPNs. But there are few reports about dynamic MR enhancement in studying SPNs. The purpose of our study was to evaluate the difference of hemodynamics between benign and malignant nodules by using dynamic contrast-enhanced MR imaging and to assess the clinical value of dynamic contrast-enhanced MR imaging in differentiating SPNs.Angiogenesis is the formation of new blood vessels from the existing vascular bed. Angiogenesis is under tight regulatory control and is observed only transiently during particular circumstances such as reproduction, development, and wound healing. Sustained angiogenesis is characteristic of several pathological conditions including tumor growth. Tumor angiogenesis was first reported by Folkman in 1971. His research found that the solid tumor can only grow to 2-3mm3 if there is no angiogenesis. indued, angiogenesis is essential for tumor growth. Angiogenesis is significantly correlated with the tumor's growth, development and metastasis.Angiogenesis is a complex multistep process. These processes are controlled by more than 20 angiogenic factors which regulate one or more of these key events. Thevascular endothelial growth factor(VEGF) is considered to be the most important and the most specific angiogenic factors. On the other hand, VEGF is a vascular infiltrating factor and correlated with lung cancer's metastasis.Now the method to quantify tumor angiogenesis is to count the microvascular density(MVD). VEGF expression is one of the methods to assess tumor angiogenesis,too. The MVD count is considered to be the golden standard to quantify tumor angiogenesis. But the MVD count is not an ideal method because it is an invasive and complex method. Because of the pathological shortcoming, the dynamic contrast-enhanced MR imaging is a convenient, non-invasive method which is a potential means to replace MVD count.At first dynamic contrast-enhanced MR imaging is used in evaluating cervical and breast cancer's angiogenesis, there are few reports in evaluating lung cancer's angiogenesis. The purpose of this study is to evaluate the relationship between dynamic contrast-enhanced MRI-derived parameters and tumor angiogenesis in peripheral pulmonary adenocarcinoma and the clinical value of dynamic contrast-enhanced MR imaging in monitoring the pulmonary adenocarcinoma's angiogenesis.Materials and Methods: Eighty-three patients with SPNs underwent dynamic contrast-enhanced MRI using Siemens Vision 1.5T MR system and a array body coil. The FLASH 2d sequence parameters for the T1 weighted imaging were TR=142ms,TE=4.1ms and the FSE(fast spin echo)sequence for the T2 weighted imaging TR=4.4ms,TE=64ms. Non-contrast MR included transversal, coronary, and sagittal imaging. Dynamic contrast-enhanced MR imaging used transversal imaging(5-6mm slice thickness, 128 256 matrix pixels,24 38cm field-of-view).The scans were performed at 20s,50s,110s,170s,230s,290s, 350s,8min,10min, 12min and 15min respectively after administration of Gd-DTPA (Magnevist, Schering Ltd.) in a standard dosage of 0. 1mmol/kg at rate of 2ml/s. The Patterns of Time-Signal intensity curve(T-SI Curve) were made. Peak height(PH), steepest slope(SS), maximum enhancement(Emax) and the enhancement rates of signal intensity at the first(El), second(E2), third(E3...
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