基于不同数学模型的扩散加权成像在乳腺肿瘤中的应用

MR扩散加权成像(DWI)是一种通过提取生物体组织内水分子扩散运动方向、扩散受限及位移偏离高斯分布程度等特征,并将其特征信息进行数字化、量化处理的成像技术。不同类型、不同分级的乳腺肿瘤,其组织间水分子的扩散方式和扩散程度存在差异,DWI能较好地反映乳腺不同肿瘤间的水分子扩散运动特征的差异,从而对不同肿瘤的鉴别诊断、肿瘤治疗后疗效评估等提供依据。就DWI的成像基础与原理及其在乳腺肿瘤的应用现状和局限性予以综述。     

单指数、双指数及拉伸指数模型扩散加权成像在卵巢良恶性肿瘤鉴别中的价值

【摘要】目的：探讨单指数、双指数及拉伸指数模型扩散加权成像鉴别卵巢良、恶性肿瘤的可行性。方法：回顾性分析36例良性卵巢肿瘤患者和34例恶性卵巢肿瘤患者的影像资料,分别测量良、恶性肿瘤组的单指数模型参数、双指数模型参数及拉伸指数模型参数值,比较良性肿瘤与恶性肿瘤各参数值的差异,分析同组间各参数值的相关性,同时采用受试者操作特征（ROC）曲线评价各参数值的阈值及诊断效能。结果：良性肿瘤的ADCstand、ADCslow、DDC及α值均高于恶性肿瘤,ROC曲线下面积分别是0.770、0.723、0.769及0.741,诊断阈值分别为1.215×10-3mm2/s、1.050×10-3mm2/s、1.230×10-3mm2/s和0.783;良、恶性肿瘤组的ADCstand与ADCslow、DDC值均呈正相关（P<0.05）,且ADCslow值低于ADCstand值（P<0.05）。结论：单指数、双指数及拉伸指数模型扩散加权成像联合应用在卵巢良恶性肿瘤鉴别中具有一定的价值。     

IVIM扩散加权成像在前列腺癌中的应用研究

前列腺癌是老年男性常见疾病,前列腺癌早期诊断是治疗和预后关键。MRI能较好显示前列腺解剖结构和相邻软组织关系,D WI是目前无创性检测活体水分子运动方法。近年来,在常规D WI基础上开发多b值体素内不相干运动（IVIM）扩散加权成像序列不仅能反映组织水分子扩散信息,亦能反映组织灌注信息。本文旨在综述IVIM-DWI原理、特点及在前列腺癌诊断中的应用。     

基于IVIM模型的扩散加权成像和动态增强核磁共振在卵巢肿瘤良恶性鉴别中的应用价值

目的 探索扩散加权成像(DWI)体素内不相干运动模型(IVIM)参数在卵巢肿瘤良恶性鉴别中的价值,以及IVIM-DWI与动态增强核磁共振(DCE-MRI)的相关性.方法 采用诊断性研究方法,搜集卵巢占位性病变且经手术、病理证实的患者共66例,其中良性肿瘤32例,恶性肿瘤34例.应用3.0T核磁共振仪和8通道心脏相控阵线圈对患者进行盆腔MRI扫描.寻找最具有良恶性卵巢肿瘤鉴别价值的IVIM参数,计算各参数的诊断界值,敏感性与特异性,应用Pearson相关性分析检验IVIM的灌注参数与DCE-MRI定量参数间的相关性.结果 表观扩散系数(ADC)、慢扩散系数(Dslow)、f*Dfast、速率常数(Kep)、Ve值在卵巢良性与恶性肿瘤之间具有统计学差异,其中ADC、Ve值敏感度较高但特异性偏低,f*Dfast、容积转运常数(Ktrans)和Kep值特异性高但敏感度极低,Dslow、Dfast和f值的特异性和敏感度都为中等.Dfast与Kep、f与Kep之间存在相关关系,但仅为弱相关(r=0.225,r=-0.317).结论 该研究所测试IVIM-DWI系数与DCE-MRI部分定量参数在卵巢良恶性肿瘤鉴别中有应用价值,其中ADC和Ve值敏感度较高,而f*Dfast和Kep值特异性较高,可以在临床诊断中作为参考指标.     

基于扩散加权成像MR模型对乳腺癌基因分型及预后的判断价值

目的 探讨基于扩散加权成像的多功能MR模型对乳腺癌基因分型及预后的判断价值。方法 选取157例经手术病理证实的乳腺癌的临床、影像资料,均行扩散加权成像及体素内不相干运动扩散加权成像、扩散峰度成像扫描,分析其定量参数表观扩散系数(ADC)、真实扩散系数(ADC_slow)、灌注相关扩散系数(ADC_fast)和灌注分数(f)及平均扩散率(MD)及平均峰度值(MK);运用多因素logistic回归分析及受试者工作特征曲线分析独立影响因素对Nottingham指数的诊断效能。结果 ER及PR阳性组的的MK值高于阴性组,且ER与MK呈轻度正相关;Her-2阴性组的ADC、ADC_slow高于阳性组,且呈极弱负相关;Ki-67与ADC、ADC_slow呈轻度负相关,与f值呈极弱正相关;淋巴结转移阳性组ADC、ADC_slow较小,呈轻度负相关,与MK呈极弱正相关;ADC、ADC_slow及MD与病理分级呈负相关,而MK值与病理分级呈轻度负相关;ADC_slow     

IVIM-DWI在女性附件病变中的应用价值研究

【摘要】目的：评估IVIM-DWI相关定量参数（ADCslow、ADCfast、f）和DWI单指数模型的定量参数（ADCstandard）在鉴别附件肿块良恶性中的诊断价值。方法：将59例行多b值（15个b值，范围0~3500s/mm2）DWI检查并经临床（1例）和病理证实（58例）的附件肿块患者纳入研究，其中附件恶性肿瘤32例，良性病变27例。由两位医师分别测量病灶的各项定量参数值（ADCstandard、ADCslow、ADCfast和f）。采用组内相关系数（ICC）评估两位观察者之间各项参数测量值的一致性。采用两独立样本非参数Mann Whitney U检验或t检验对良恶性组之间各项定量参数值的差异进行分析。采用受试者工作特征（ROC）曲线分析各项定量参数诊断附件恶性病变的诊断效能。结果：两位医师测量的各项DWI定量参数值的差异均无统计学意义（P>0.05），各项参数在两位医师间的一致性均较好（ICC为0.846~0.959）。四项定量参数中ADCstandard、ADCslow及f值在良恶性组之间的差异有统计学意义（P<0.05）。ROC曲线分析显示，ADCstandard、ADCslow及f的曲线下面积分别为0.890、0.893和0.630。结论：多b值DWI检查中ADCstandard及ADCslow对附件良恶性病变的鉴别诊断价值较高，而ADCfast和f的鉴别诊断价值相对较小。     

心脏单、双指数扩散加权成像的应用进展

心肌组织的水分子扩散运动和微循环灌注是评估患者心肌状况和监测治疗效果的重要指标[1].随着MRI的发展,单b值、多b值扩散加权成像(DWI)在心脏中的应用越来越多,因其能够在不使用造影剂的情况下获得组织的扩散和灌注信息[2].本文拟对单、双指数DWI在心脏中的应用进展做一综述.     

体素内不相干运动扩散加权成像在诊断肺癌中的初步应用

目的：探讨体素内不相干运动扩散加权成像(IVIM-DWI)对不同病理类型肺癌的诊断价值。方法45例患者行常规MR 序列及多 b 值扩散加权成像(DWI)扫描,经 AW4.5工作站后处理得到慢速表观扩散系数(Slow-ADC)、快速表观扩散系数(Fast-ADC)及快速扩散所占比率(ffast ),并分析其在不同病理类型肺癌间的统计学差异以及与肺癌血清肿瘤标志物(TM)的相关性,利用受试者工作特征曲线(ROC)评价各参数的诊断效能。结果45例肺癌患者包括非小细胞肺癌(NSCLC)27例(鳞癌13例、腺癌14例),小细胞肺癌(SCLC)18例。SCLC 组 Slow-ADC 值与 NSCLC 组(P =0.00)、腺癌组(P =0.03)、鳞癌组(P =0.01)之间均有统计学差异;各组间 Fast-ADC 及 ffast 值差异均无统计学意义。Slow-ADC 值的 ROC 曲线下面积(AUC)为0.874。鳞癌组鳞状上皮细胞癌抗原(SCC-Ag)水平与 Slow-ADC 值之间存在负相关(r=-0.730)。结论IVIM-DWI 参数中 Slow-ADC 值对 NSCLC与 SCLC 的鉴别诊断有显著意义,诊断效能最大。SCC-Ag 与 Slow-ADC 间存在相关性,对不同病理类型肺癌的诊断有一定的意义。     

Whole-body diffusion-weighted magnetic resonance imaging

Diffusion-weighted magnetic resonance imaging (DWI) provides information on the diffusivity of water molecules in the human body. Technological advances and the development of the concept of diffusion-weighted whole-body imaging with background body signal suppression (DWIBS) have opened the path for routine clinical whole-body DWI. Whole-body DWI allows detection and characterization of both oncological and non-oncological lesions throughout the entire body. This article reviews the basic principles of DWI and the development of whole-body DWI, illustrates its potential clinical applications, and discusses its limitations and challenges.     

DWI技术在肝外胆管细胞癌诊断、分期和 疗效评估中的研究进展

肝外胆管细胞癌（EHCC）是第二大原发性肝胆系统肿瘤,其恶性程度高,预后不良。扩散加权成像（DWI）是反映组织水分子扩散运动的常用无创性成像方法。近年来,DWI及体素内不相干运动（IVIM）、扩散张量成像（DTI）及扩散峰度成像（DKI）等衍生技术已广泛应用于EHCC的诊断、病理分期预测和监测以及疗效评估。就DWI及其衍生序列对EHCC应用的研究进展以及局限性和应用前景予以综述。     

Updates in advanced diffusion-weighted magnetic resonance imaging techniques in the evaluation of prostate cancer

Diffusion-weighted magnetic resonance imaging (DW-MRI) is considered part of the standard imaging protocol for the evaluation of patients with prostate cancer. It has been proven valuable as a functional tool for qualitative and quantitative analysis of prostate cancer beyond anatomical MRI sequences such as T2-weighted imaging. This review discusses ongoing controversies in DW-MRI acquisition, including the optimal number of b-values to be used for prostate DWI, and summarizes the current literature on the use of advanced DW-MRI techniques. These include intravoxel incoherent motion imaging, which better accounts for the non-mono-exponential behavior of the apparent diffusion coefficient as a function of b-value and the influence of perfusion at low b-values. Another technique is diffusion kurtosis imaging (DKI). Metrics from DKI reflect excess kurtosis of tissues, representing its deviation from Gaussian diffusion behavior. Preliminary results suggest that DKI findings may have more value than findings from conventional DW-MRI for the assessment of prostate cancer.     

Intravoxel incoherent motion (IVIM) in evaluation of breast lesions: Comparison with conventional DWI

Objectives

To obtain perfusion as well as diffusion information in normal breast tissues and breast lesions from intravoxel incoherent motion (IVIM) imaging with biexponential analysis of multiple b-value diffusion-weighted imaging (DWI) and compare these parameters to apparent diffusion coefficient (ADC) obtained with monoexponential analysis in their ability to discriminate benign lesions and malignant tumors.

Materials and methods

In this prospective study, informed consent was acquired from all patients. Eighty-four patients with 40 malignant tumors, 41 benign lesions, 30 simple cysts and 39 normal breast tissues were imaged at 1.5 T utilizing contrast-enhanced magnetic resonance imaging (MRI) and DWI using 12 b values (range: 0–1000 s/mm²). Tissue diffusivity (D), perfusion fraction (f) and pseudo-diffusion coefficient (D*) were calculated using segmented biexponential analysis. ADC (b = 0 and 1000 s/mm²) was calculated with monoexponential fitting of the DWI data. D, f, D* and ADC values were obtained for normal breast tissues, simple cysts, benign lesions and malignant tumors. Receiver operating characteristic analysis was performed for all DWI parameters.

Results

There was good interobserver agreement on the measurements between the 2 observers. D values were significantly different among malignant tumors, benign lesions, simple cysts and normal breast tissues (P = 0.000) and it was the same result for f, D* and ADC values. Further comparisons of these 4 parameters between every single pair were as the following. D and ADC values of malignant tumors were significantly smaller than those of benign lesions, simple cysts and normal tissues (P = 0.000, respectively). The f value of malignant tumors was significantly higher than that of benign lesions, simple cysts and normal breast tissues (P = 0.001, P = 0.000, and P = 0.000). D and ADC values demonstrated higher sensitivity and specificity in differentiating benign lesions and malignant tumors, with area under the curve (AUC) of 0.952 and 0.945, respectively, while f and D* with the lower AUC of 0.723 and 0.630, respectively. Combining f and D values had a sensitivity up to 98.75%.

Conclusion

DWI response curves in malignant tumors, benign lesions and normal fibroglandular tissues are found to be biexponential fit in comparison with the monoexponential fit for simple cysts. IVIM provides separate quantitative measurement of D for cellularity and f and D* for vascularity and is helpful for differentiation between benign and malignant breast lesions.     

DWIBS对转化型淋巴瘤的诊断价值及与Ki-67标记指数的相关性研究

目的:探讨背景抑制全身扩散加权成像(DWIBS)在转化型淋巴瘤诊断方面的应用价值及其与Ki-67标记指数的相关性.方法:回顾性分析12例经病理确诊的转化型淋巴瘤患者的临床资料,患者转化前后均行DWIBS扫描.针对患者Ki-67病理采集区域测量平均ADC值,同时测量转化前后所有受累淋巴结的ADC值,选取最小值作为ADCm...     

The prediction of the treatment response of cervical nodes using intravoxel incoherent motion diffusion-weighted imaging

PurposeTo investigate the predictive role of Intravoxel Incoherent Motion Diffusion-Weighted Imaging (IVIM-DWI) parameters on cervical nodal response to chemo-radiotherapy (CRT) of head and neck squamous cell carcinoma (HNSCC).Materials and methodsPatients with pathologically confirmed HNSCC were included in the present prospective study, having at least one positive cervical lymph node (LN). They received concomitant CRT and underwent three serial IVIM-DWI investigations: before, at mid-treatment and after treatment completion. Tissue diffusion coefficient D, perfusion-related diffusion coefficient D* and perfusion fraction f were calculated by a bi-exponential fit. The two-sided Mann–Whitney rank test was used to compare the imaging parameters of patients with regional failure (RF) and regional control (RC). A p value lower than 0.05 was considered to be statistically significant.ResultsThirty-four patients were accrued. Twenty-four out of 34 LN (70.6%) showed persistent RC after a median follow-up time of 27.6 months (range: 12.0–50.2 months), while ten cases of RF (29.4%) were confirmed with a median time of 6.8 months (range: 1.5–19.5 months). Patients with RC showed significantly lower pre-treatment D values compared to the RF patients (p = 0.038). At mid-treatment, the patients with RF showed significantly higher D values (p = 0.025), and exhibited larger percent reductions in f and the product D* × f from the baseline (p = 0.008 and <0.001, respectively). No additional information was provided by the examination at the end of treatment.ConclusionPre-treatment and mid-treatment IVIM-DWI showed potential for prediction of treatment response of cervical LN in HNSCC patients.     

背景抑制全身扩散加权成像口服枸橼酸铁铵泡腾颗粒消除胃肠道干扰的可行性

目的:探讨口服枸橼酸铁铵泡腾颗粒(FAC)对背景抑制全身扩散加权成像(DWIBS)图像质量及其定量参数的影响.方法:2019年9-11月招募15名健康志愿者,年龄23～53岁(38.2±12.5岁),分别于空腹和口服FAC 20 min后行DWIBS扫描.测量并计算b=800、1500、2000 s/mm2图像上胃、十...     

成年正常胰腺多b值DWI参数与性别、年龄的相关性研究

目的:探讨性别、年龄因素对成年正常胰腺多b值DWI参数的影响。方法:回顾性分析57例胰腺正常患者(男36例,年龄21~68岁,平均43.9±11.4岁;女21例,年龄24~59岁,平均46.8±9.7岁)的临床及影像资料,利用上腹部多b值DWI(b值=0、20、50、100、200、400、600、800及1000s/mm2)测量每个患者从胰腺头到尾部单指数模型参数ADCtotal值和双指数模型参数ADCfast、ADCslow和f值,并计算每个胰腺平均ADCtotal、ADCfast、ADCslow和f值。使用独立样本t检验分析不同性别患者的年龄分布差异;采用独立样本非参数Mann-Whitney U检验分析不同性别间各参数平均值差异;利用Pearson相关分析方法分析平均ADCtotal、ADCfast、ADCslow和f值与年龄的相关性。结果:女性正常胰腺平均ADCtotal、ADCfast、ADCslow和f值[分别为(1.45±0.15)×10-3、(13.17±4.91)×10-3、(0.88±0.18)×10-3 mm2/s和(0.370±0.063)]皆低于男性[分别为(1.55±0.17)×10-3、(15.77±7.83)×10-3、(0.91±0.15)×10-3 mm2/s和(0.372±0.056)],但男、女性间各参数平均值均无显著性差异(P均>0.05)。Pearson相关分析表明成年正常胰腺平均ADCtotal、ADCfast和ADCslow值与年龄有显著相关性(相关系数r分别为:-0.315、-0.340和-0.300;P值分别为0.017、0.010和0.023);f值与年龄无显著相关性(相关系数r=0.048,P=0.725)。结论:成年正常胰腺平均ADCtotal、ADCfast和ADCslow随着年龄增加而减小。利用多b值DWI研究胰腺相关疾病时,不可忽略志愿者年龄因素对ADCtotal、ADCfast和ADCslow的影响。