【作者】 陆玮；

【导师】 夏黎明；

【作者基本信息】 华中科技大学 ， 医学影像学与核医学， 2012， 硕士

【摘要】 目的：通过测量乳腺各种疾病的单指数模型ADC值，双指数模型Fast ADC值、SlowADC值、快速ADC成分所占比例，比较乳腺不同疾病之间各参数间的统计学差异，探讨单指数、双单指数的DWI成像在乳腺病变的应用价值。材料和方法：收集40例经临床诊断为乳腺肿块病人，对所有患者进行MRI常规平扫、单b值弥散加权成像（取b=0,800s/mm²）、多b值弥散加权成像、MRI动态增强扫描。多b值弥散加权成像采用11个b值，最大b值为3000s/mm²。利用AW4.4工作站对各乳腺疾病的单指数、双单指数的DWI原始图像进行分析，分别测量各疾病的单b值的ADC值（apparent diffusion coefficient，ADC），标准表观扩散系数值（standardapparent diffusion coefficient，ADCSt），快速表观扩散系数值（fast apparent diffusioncoefficient，ADCFast），慢速表观扩散系数值（slow apparent diffusion coefficient，ADCSlow），快速扩散所占比率（fraction of fast ADC，ffast）。结果：1、各类乳腺肿块的单指数信号衰减模型测得的ADCmono值有显著差异，从大到小依次为：正常腺体>良性病变>恶性病变，囊肿的ADCmono范围跨度较大。2、双指数信号衰减模型测得乳腺囊肿ADCfast、ADCslow均较对照组正常乳腺腺体组织大，差异有统计学意义。3、乳腺良性肿块参数与乳腺正常组织比较只有ffast有统计学差异，但ADCfast、ADCslow有明显规律，ADCfast遵循顺序：乳腺腺瘤伴纤维结节<导管内乳头状瘤<腺瘤伴黏液样变<慢性淋巴结细胞性乳腺炎； ADCslow遵循循序：乳腺腺瘤伴纤维结节<导管内乳头状瘤≈慢性淋巴结细胞性乳腺炎<腺瘤伴黏液样变。4、II级浸润性导管癌（n=21）慢速ADC平均值（ADCslow=0.573±0.122mm²/s）显著低于正常腺体组织（ADCslow=0.974±0.342mm²/s）；肿瘤快速ADC平均值(ADCfast=3.877±1.96510^-3mm²/s)与正常腺体组织快速ADC平均值(ADCfast=3.613±0.67010^-3mm²/s)没有显著差异，但是它的快速成分所占比例ffast与正常腺体快速成分所占比例有差异（II级浸润性导管癌ffast=0.289±0.131，正常腺体组织ffast=0.534+0.198）。良恶性病灶组间对比也发现明显类似的规律。结论：单、双指数不同ADC值在诊断乳腺良、恶性病灶，各具有其优点，正常组织、良性病灶、恶性病灶单指数信号衰减模型ADCmono有显著统计学差异。双指数衰减模型计算的正常腺体、良性病灶、恶性病灶的参数（ffast、fslow、ADCslow）有统计学差异，而ADCfast没有显著统计学差异，从这一点来推测，双指数ADC值反应的是肿瘤密度特点，乳腺肿瘤ADC值下降主要归因于细胞成分比例的增加而不是细胞外成分比例的减少，细胞内水分子扩散受限，从而导致ADCSlow较低。更多还原

【Abstract】 Objective: Many studies have reported the importance of attenuation of Apparent DiffusionCoefficient （ADC） values of DWI signal to identify benign and malignant breast lesions.But tissues in vivo don’t display a linear mono-exponential decay of ADC values, but rathera bi-exponential one; and thus they could be divided into fast （ADCfast） and slow （ADCslow）diffusion component using a simple bi-exponential decay model. The purpose of this studywas to examine the non mono-exponential characteristics of the diffusion weightedmagnetic resonance imaging signal attenuations of breast, to estimate the fast and slowdiffusion components, and to compare them with pathological specimen. Fifty one casesof clinical breast lumps were collected who underwent a preoperative single-b and multi-bDWI. The DWI signal attenuations were analyzed using mono-exponential andbi-exponential decay function; and the ADC, ADCfast, ADCslow; and fraction of fast ADCwere calculated and compared.Materials and Methods: Patients with clinically and pathologically proven breast lumpswere collected and studied with conventional MRI scan, single-b DWI （with b=0,800s/mm²）, multi-b DWI （with11different b values up to3000s/mm²）, and dynamiccontrast-enhanced MRI scan. The multi-b DWI from the normal and abnormal portions ofthe breast tissue were analyzed and compared; and reconstruction of the ADC map, ADCfastmap, ADCslowmap and fraction of fast ADC were done using using AW4.4workstation.Results: The ADCmonoof various types of lesions were significantly different, in decreasingorder of: normal glands> benign lesions> malignant lesions; while the ADCmonoof cyst hada wide range of values. The ADCfast, ADCslowof cysts using bi-exponential signalattenuation model was greater than the parameters in the group of normal glandular tissue,and the difference was statistically significant. In parameters of benign breast lesion just ffasthad significant difference, whereas the ADCfastand ADCslowobviously follow the same decreasing order sequence: fibrous nodules <intraductal papilloma <fibrous nodules withmyxomatous change <chronic lymphocytic mastitis. Slow component （ADCslow=0.573±0.122mm²/s） of invasive ductal carcinoma II （n=21） was significantly lower than normalglands （ADCslow=0.974±0.342mm²/s）; their fast component (ADCfast=3.877±1.965×10^-3mm²/s) almost equal to the normal glandular tissue (ADCfast=3.613±0.670×10^-3mm²/s), but the fraction of the fast component （ffast） had significant difference （fraction offast component of cancer tissue ffast=0.289±0.131; fraction of fast component of normalglands ffast=0.534+0.198）. The benign and malignant lesions group also had a similarfinding.Conclusion: Analysis of DWI signal attenuation of breast tumours using mono and bi-exponential function shows that ADCmonousing mono-exponential signal attenuation modelhave statistically significant differences. The parameters of normal glands, benign lesionsand malignant lesions （ffast, fslow, ADCslow） using bi-exponential decay model also havesignificant differences, whereas ADCfasthas no statistically significant differences. Thisresult suggests that the main reason for the decrease in ADC values of a breast tumour isdecrease in fraction of the fast component and the increase in fraction of the slowcomponent having a low ADC values rather than the decrease in ADC values of the fastcomponent by the restricted water diffusion in the reduced extracellular spaces.更多还原