| Angiogenesis, by which new blood vessels are generated, is a fundamental physiological process required for development, reproduction, and response to ischemia. Pathologic angiogenesis, often referred to as neovascularization, is associated with some disease condition, including wound repair, arthritis, and so on. In 1971, Folkman first hypothesized that solid tumors remain growth restricted to 2-3 mm in diameter until the onset of angiogenesis. Subsequent investigations have broadened the study of angiogenesis in the following more than twenty years. Recently, numerous studies have shown a statistically significant correlation between tumor angiogenesis and development, invasion, metastasis, staging, and prognosis.Although the histological mircovessel density (MVD) technique is the current gold standard to characterize tumor angiogenesis, it may not be an ideal tool for clinical purposes, because it is invasive, prone to sampling errors, and lack of the information about functional angiogenesis activity. A method for estimating tumor angiogenesis activity in vivo would be desirable clinically, particularly if the method were quantitative, noninvasive, able to sample the entire tumor, and could be repeated at frequent intervals. Hence, a number of available imaging modalities, such as ultrasonography (US), computed tomography (CT), magnetic resonance imaging6(MRI), positron emission tomography (PET), have been proposed and tested to evaluate tumor angiogenesis, in both laboratory experiment and clinically practice. However, most of the clinical studies are focused on breast tumors.Magnetic resonance imaging (MRI) is a widely employed diagnostic method for the evaluation of patients with tumors. This method is noted for its remarkable soft-tissue definition, absence of ionizing radiation, high spatial and temporal resolution, and ability to generate images in any plane of entire body. With the improvement of MR techniques, It becomes possible to assess the spatial and temporal heterogeneity of tumor microcirculation with dynamic contrast-enhanced MRI (DCE-MRI).In this study, The relationship between DCE-MRI-derived patterns and histological MVD counts was analyzed, in order to investigate value of DCE-MRI on assessing angiogenesis on lung cancer.Materials and MethodsPatient population: Between April 2000 and February 2002, 50 consecutive patients (37 men, thirteen women; age rang, 31~80 years) with definite masses detected by chest X-ray and (or) CT were examined with DCE-MRI. None of the patients had been treated with anticancer drugs before MRI and surgery. All the patients received the MRI procedure within one week before surgery. And all lesions were confirmed by pathologic examination after surgical resection. The clinical document (including operating record, histological report, and situations of lymphatic involvement) is integrated.MRI protocol. All the MR exams were performed on a 1.5-T MR scaner (Signa Horizon LX; GE Medical system) using a phase-array torso surface coil. Axial or coronary TjWI SE and TaWI FSE were acquired.-7-Dynamic studies were performed with FSE sequence (TR/TE:700/9ms; 256x128 matrix; 5 mm slice with 1.0 mm gap). After a reference imaging, gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA, magnevist, O.lmmol/kg) was administered by hand as a bolus injection at a dose of 0.1 mL/kg body weight with a rate of 2 mL/second. Acquisition of the initial section was timed at 10 seconds after the initial injection. Sequential multiphase images covering the entire lesion were continuously acquired in either axial or coronary plane at a 12-18 seconds scan time per phase for 4 minutes. The total examination time was about 45 minutes.The automated processing of the acquired dynamic MRI data sets on a pixel-by-pixel basis for each section was performed by using Functool 2000 software on a workstation (GE AW3.1). Time-Signal Intensity Curves (T-SI Curves) of lesions were plotted. Patterns of T-SI Curves were assessed based on the information of S...
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