【作者】 邓义；

【导师】 刘斯润；

【作者基本信息】 暨南大学 ， 影像医学与核医学， 2010， 硕士

【摘要】 第一部分背景信号抑制全身弥散加权成像正常表现和b值选择探讨目的：研究正常成人的背景信号抑制全身弥散加权成像(WB-DWIBS)影像表现；探讨分析WB-DWIBS的合适b值。材料与方法：正常健康志愿者39人,其中13位志愿者同时进行了多个不同b值(b=0,600；0,800；0,1000)的WB-DWIBS检查,其他26人所选的b值为0,800。扫描完成后,将采集到的图像数据输入到SUN ADW4.2图像工作站行图像后处理,3D-MIP重组,黑白灰阶反转,观察每个部位的信号特点。建立图像评估标准,建立评分指标。在盲法原则下,由两位影像诊断医师对不同扫描条件下的各位志愿者的WB-DWI原始图和3D-MIP重组图像进行评分。SPSS 11.5统计分析软件,采用多个相关样本比较的FriedmanM检验和配对样本的Wilcoxon秩和检验。结果：1、不同的b值图像质量之间总体上存在差异,差异具有统计学意义。从低b值到高b值图像质量逐步降低,b=0,1000组的图像质量不佳,部分层面图像质量影响诊断。b=600与b=800的图像质量差异无统计学意,b=600与1000、b=800与1000组间图像质量差异具有统计学意义。2、全身不同的器官和组织结构信号有不同的信号特点。结论：1、对于b=0,600；0,800；0,1000的三种参数,初步认为b=0,800较为适合全身弥散加权成像。2、全身不同的器官和组织结构有不同的信号特点。目前的WB-DWI技术还不完善,3D-MIP图像还存在一定的变形和伪影。第二部分背景信号抑制全身弥散加权成像的可重复性研究目的：探讨背景信号抑制全身弥散加权成像测量体部脏器ADC值的可重复性。材料与方法：正常健康志愿者16名,用GE1.5T MR,自由呼吸状态下行背景信号抑制全身弥散加权成像(WB-DWIBS)扫描,并且以完全相同的参数对中上腹部进行三次重复扫描,在SUN ADW4.2工作站测量前后三次肝脏和双肾的ADC值。由同一测量者在同一工作站,对16名志愿者同一次扫描的肝肾ADC值进行了前后两次测量,两次测量的时间间隔为一个月。采用SPSS11.5对数据进行组内相关系数分析和Pearson相关系数分析。结果：所有患者均获得良好的全身DWI图像。前后三次测量肝脏和双肾的ADC值具有良好的一致性,肝左、右叶和双肾的组内相关系数分别为0.89、0.90、0.80、0.82。测量误差的信度分析：16名志愿者的肝左、右叶和双肾图像的ADC值前后两次测量,经Pearson相关系数分析,r值分别为0.76,0.83,0.75,0.78；P值分别为0.018,0.006,0.020,0.009；按α=0.05水准,结果表明,两次测量间数值具有较高相关性,测量误差小,精确性较高。结论：自由呼吸背景信号抑制全身弥散加权成像测量肝脏、双肾等腹部脏器的ADC值具有良好的可重复性,可进一步用于临床研究。第三部分背景信号抑制全身弥散加权成像对恶性肿瘤的筛查价值目的：研究恶性肿瘤的背景信号抑制全身弥散加权成像(WB-DWIBS)的影像表现,评价其在恶性肿瘤筛查中的作用。材料与方法：32例恶性肿瘤病患者,所有肿瘤原发灶和转移病灶均经病理、常规影像或者随访证实。所有患者均无磁共振检查禁忌,且知情同意。所有患者均行WB-DWI检查,b值取0,800 s／mm2；同时用FSE T2WI扫描。将MR扫描原始数据输入SUN ADW 4.2工作站,进行3D-MIP方法重组。WB-DWI结合b=0 T2WI和常规T2WI-ADC图像融合方法定位肿瘤病灶。在ADC图上测量ADC值；测量正常对照组20位志愿者的40枚淋巴结(本研究第一部分采集的资料)和恶性肿瘤组20位患者的40枚淋巴结转移瘤ADC值。用SPSS11.5统计软件进行两个独立样本的t检验。结果：成功采集所有患者的WB-DWI图像,3D-MIP直观显示肿瘤病灶。肿瘤病灶呈明显高信号,在反转图上呈低信号影。32例患者当中,发现骨转移14例,淋巴结转移26例,脏器转移12例。没有发现假阳性病灶。WB-DWI结合b=0的T2WI和常规T2WI-ADC图像融合可以准确定位肿瘤病灶。1例脑转移瘤病灶在WB-DWI显示欠清晰,需要结合T2WI图。肺内的部分小的转移瘤病灶、颅骨转移瘤病灶(小于1cm)在WBD原始图和3D-MIP图上均未能显示。肿瘤患者淋巴结转移瘤的ADC值为(1.39±0.23)×10-3mm2／s；正常成人对照组淋巴结的ADC值为(1.64±0.28)×10-3mm2／s,两组之间差异有统计学意义(按α=0.05水准)。结论：1、WB-DWI可以清晰显示弥散受限的肿瘤病灶,是恶性肿瘤筛查的有效方法。2、WBD-DWI能准确和敏感地显示淋巴结,是全身淋巴结MR成像的有效手段,ADC值测量可以为诊断淋巴结转移提供有效信息。3、WB-DWI需要结合常规MR,帮助病灶定位与发现小病灶(<1cm)。更多还原

【Abstract】 Part one Normal image characteristics of whole body diffusion-weighted imaging and choice of b valueObjective:To study the normal adult image characteristics of whole body diffusion weighted imaging. To investigate the appropriate b value of whole body diffusion weighted imaging. Material and Methods:39 healthy volunteers, three different weightings (b=600,800,1000s/mm2) were applied in thirteen volunteer, b=800 were applied in the others in whole body diffusion weighted imaging on 1.5T MR machine. After the completion of scan, the collected image data was imputed to SUN ADW4.2 image workstation, to carry out 3D-MIP reformation, black and white gray-scale inversion and observe the signal characteristics of each site of the whole body. According to the image evaluation standards, WB-DWI original images and 3D-MIP images was assessed by two Imaging Physicians under blind method. SPSS 11.5 was used for data analysis with FriedmanM compared a number of related samples test and Wilcoxon paired sample rank sum test.Result:1, image quality with different b values differences in the whole, the difference was statistically significant. Image quality gradually decreased, from low b value to high b value. Image quality of b=0,1000 group are poor, some slices of the image influence the diagnosis. b = 0,600 and b=0,800 the image quality difference was not statistically significant. b= 600 and b=1000, b=800 and b=1000 image quality difference was statistically significant.2, the various organs and tissues of whole body have different signal characteristics. The current WB-DWI technology is not perfect, the images still exist a certain degree of deformation and artifacts.Conclusions:1, for b=0,600; 0,800; 0,1000 three parameters, b=0,800 is more appropriate for the body diffusion weighted imaging.2, the various organs and tissues of whole body have different signal characteristics. The current WB-DWI technology is not perfect, the image still exists a certain degree of deformation and artifacts. Part two Reproducibility study of free breathing whole body diffusion weighted imagingObjective:To explore the reproducibility of apparent diffusion coefficient (ADC) measurement of the normal liver and kidneys in whole body diffusion-weighted imaging.Material and Methods:sixteen healthy volunteers underwent whole body diffusion-weighted imaging with background signal suppression (DWIBS) at b-values of 0 and 800s/mm2. The upper abdomens were scanned three times with the same parameters. All images were acquired on GE 1.5T MRI scanner. Data was imputed to SUN ADW 4.2 workstation. The ADC map was obtained by using functool soft ware and then to calculate the ADC value of liver and kidneys. SPSS 11.5 was used to analysis data. Reproducibility was assessed by ICC. In the same workstation, ADC values of the liver and kidneys were measured twice on 16 volunteers with the same scan, Using SPSS11.5 Pearson correlation coefficients analysis.Result:All patients have high quality image of whole body DWI. Three times measurements of the ADC values of the liver and kidneys are of good consistency. The intraclass correlation coefficients of Left lobe and right lobe and kidneys were 0.89,0.90,0.80,0.82respectively. Respect to the reliability of measurement error, the twice ADC measurement of the liver left lobe and right lobe and kidneys of 16 volunteers by the Pearson correlation coefficient, r values were 0.76,0.83,0.75,0.78, P values were 0.018,0.006,0.020,0.009, toα=0.05 for the standard, the results show that the values between two measurements with high correlation, measurement error is small, high accuracy.Conclusions:The measurement of ADC value of the abdominal organs such as liver and kidneys have good repeatability in free-breathing whole diffusion-weighted imaging with background signal suppression, which can be further applied to the clinical research. Part three Clinical value of whole body diffusion weighted imaging with background suppression in screening malignant tumorObjective:To study the whole body diffusion weighted imaging with background suppression (WB-DWIBS) imaging features of malignant tumors, to assess the clinical value of WB-DWIBS in screening malignant tumor.Material and Methods:32 cases of malignant tumor patients, all primary tumors and metastasis lesions were confirmed by pathology, conventional imaging or follow-up. All patients were informed consent and had no check contraindications of MRI. All patients underwent whole body diffusion weighted imaging examination; b values were 800 s/mm2. FSE T2WI was also scanned in the same time. Imputed the data to SUN ADW 4.2 Workstation and then do 3D-MIP reformation, and measured ADC value on ADC maps. WB-DWI combined with b=0 T2WI and T2WI-ADC image fusion locate the lesions. To Measure ADC value of lymph node metastases of tumor cases and ADC value of lymph nodes of normal adult control group (data come from the first part of this study).Result:Successfully collected images of all patients, the whole body MIP map show restricted diffusion lesions. WB-DWI combined with b=0 T2WI and T2WI-ADC image fusion can accurately locate the lesions. Showed high signal lesions were evident in the inverted map, which showed low signal intensity. Among 32 patients, bone metastasis was found in 14 cases, 26 cases with lymph node metastasis, visceral metastasis in 11 cases and found no false-positive lesions.One case of brain metastasis lesions showed less clear, requires a combination of T2WI conventional MR. Part of small metastasis lesions of the lung and skull metastasis lesions (< lcm) don’t be displayed in WB-DWI. To measure ADC value of metastatic lymph nodes, the average was (1.39±0.23)×10-3mm2/s; the mean ADC value of normal adult control group was (1.64±0.28)×10-3 mm2/s, the difference between the two groups was statistically significant (α=0.05).Conclusions:1, Restricted diffusion tumor lesions can be clearly displayed in WB-DWI,which is an effective way in malignant tumor screening.2, WBD-DWI can accurately and sensitively shows lymph nodes, which is an effective way of whole body lymph node imaging. ADC value measurement can provide useful information for diagnosis of lymph node metastasis.3, WB-DWI requires a combination of conventional MR to help locate and find small lesions(< 1cm).更多还原