【作者】 曾泳瀚；

【导师】 刘筠； 钟进；

【作者基本信息】 天津医科大学 ， 影像医学与核医学， 2008， 硕士

【摘要】 图像融合是把相同或不同成像模式的图像进行一定的变换处理,以一种新的图像方式显示源图像所包含信息,达到优势互补、综合利用的目的。本研究尝试使用开源图像处理软件（OsiriX）对颈部DWI功能图像和常规MRI解剖图像进行融合,以期提高影像检查的诊断准确性。目的:探讨颈部扩散加权成像（DWI）与常规MRI图像融合的可行性,并评价其对颈部淋巴结病变的临床应用价值。对象与方法:1、参数优化:健康志愿者18名,其中男性10例,女性8例,年龄21～35岁,平均年龄29岁。扫描设备使用Marconi Eclipse 1.5T磁共振扫描仪和颈部相控阵线圈。DWI采用单次激发SE-EPI序列和STIR序列,分别取b值300s/mm²、500s/mm²、1000s/mm²行常规MRI和DWI序列的轴位及冠状位扫描。比较不同b值和成像断面的图像质量,并将DWI图像与常规MRI图像进行融合。2、临床评价:对32例单侧或双侧颈部淋巴结肿大患者行常规T₁WI、T₂WI轴位、冠状位和DWI冠状位扫描,其中恶性病变22例,良性病变10例,均经病理及随访证实。扫描完成后,使用开源图像处理软件OsiriX将相同视野、层厚和层距的DWI和T₁WI冠状位图像进行融合。比较DWI/T₁WI融合图像、DWI及T₂WI三种图像显示病变的能力,同时应用受试者操作特征（ROC）曲线比较DWI/T₁WI联合检查与单纯T₂WI鉴别良恶性淋巴结的准确性,并分析良、恶性淋巴结ADC值差异的统计学意义。结果:1、DWI冠状位图像与常规MRI图像空间位置匹配度高,图像质量明显优于轴位图像,经x²检验,两种成像平面的差异有统计学意义（P=0.000）。不同b值下的SNR值间的差异有统计学意义（P＜0.05）;不同b值下所测ADC值间的差异亦有统计学意义（P＜0.05）。选择b值为500s/mm²时的冠状位DWI图像与相应的常规MRI图像进行融合,可获得满意的融合图像。2、与T₂WI比较,DWI和DWI/T₁WI融合图像能更敏感地发现淋巴结。DWI/T₁WI显示病变的能力明显优于DWI,差异有统计学意义（P＜0.01）。经ROC曲线分析,DWI/T₁WI联合检查的诊断准确性优于单纯T₂WI,两者曲线下面积分别为0.943和0.793,差异有统计学意义（P＜0.01）。Kappa检验显示DWI/T₁WI（K=0.872）的诊断一致性高于T₂WI（K=0.643）。恶性淋巴结的平均ADC值为（0.948±0.167）×10^-3mm²/s,良性淋巴结的平均ADC值为（1.459±0.141）×10^-3mm²/s,恶性淋巴结组平均ADC值小于良性淋巴结组,差异有统计学意义（P＜0.05）。结论:通过优化扫描参数,可实现颈部DWI功能图像和常规MRI解剖图像的融合;DWI和常规MR/融合图像在很大程度上克服了DWI的图像缺乏解剖信息的缺点,有助于提高影像诊断的准确性。更多还原

【Abstract】 Image fusion means to transform imaging data obtained from the same or different imaging modalities and create a new image including source images information.The purpose of image fusion is to merge complementary information from multimodalities data for clinical diagnosis.We tried using the open source image processing software,OsiriX,to combine function image with anatomy image in order to provide more helpful information for the clinical management.Objective:To study the feasibility of image fusion between diffusion-weighted image and conventional MRI in neck by adjusting the scanning parameters and to evaluate the usefulness of clinical application for cervical lymphadenopathy.Objects and Methods:①Parameter Optimization:Axial and coronal conventional MRI and DWI scans with three different b values（300s/mm²、500s/mm²、1000s/mm²）were performed in 18 normal volunteers who ranged in age from 21 to 35 years old（10 male,8 female,mean age 29 years）.MR scanning were performed on Marconi Eclipse 1.5T scanner with cervical phased array coil and DWI was performed with single shot echo planar imaging technique and short time inversion recovery sequence.Image quality with different b values and section were compared and image data were processed with software packages.②Clinical Evaluation:Conventional MRI and DWI scans were performed in 32 patients who had pathology and follow-up proven malignant tumors（22）and benign lesions（10） by using Marconi Eclipse 1.5T scanner with cervical phased array coil.DWI images and T₁WI images with the same field of vision,thickness and interval were fused by using image processing software.The ability of detection of DWI/T₁ WI,DWI and T₂WI images and the diagnostic accuracy of T₂WI and DWI/T₁WI in showing lesions were compared.The difference of ADC values between two kinds of lymph nodes was also analyzed.Results:①The image quality of coronal scan is better than axial scan,there was significant difference between the two scan planes（P=0.000）.Statistically significant difference（P＜0.05）was found in SNR values with different b values（300s/mm²、 500s/mm² and 1000S/mm²）.The study also suggested the ADC values with diffrent b values had significant statistical difference.We fused coronal DWI（b values= 500s/mm²）and conventional MRI image data and obtained satisfactory fusional image.②DWI and DWI/T₁WI could more sensitively show lymph nodes than that of conventional MR（T₂ WI）.The ability of detection for DWI/T₁ WI was better than DWI and significant statistical difference was found（P＜0.01）.The area under the curve（AUC）of the composite receiver operating characteristic（ROC）curve of DWI/T₁WI（0.943）was significantly higher than those of T₂WI（0.793;P＜0.01）. Kappa values were 0.872（high）for DWI/T₁WI and 0.643（moderate）for T₂WI.Mean ADC values of malignant lymph nodes was（0.948±0.167）×10^-3mm²/s,mean ADC values of benign lymph nodes was（1.459±0.141）×10³mm²/s,there was significant difference in two kinds of lymph nodes（P＜0.05）.Conclusion:By adjusting the scanning parameters,image fusion between diffusion-weighted image and conventional MRI in neck is feasible.Fusion image of diffusion-weighted image with conventional MRI can obviously improve spatial resolution of DWI,and may improve accuracy of imaging diagnosis.更多还原