Diffusion-weighted Single-shot Echo Planar MR Imaging of Normal Human Prostate Using Different b Values

This study examined the effect of different b values on diffusion-weighted MR imaging （DWI） of human prostate by using single-shot spin echo echo planar imaging （SE-EPI） sequences, observed the normal appearances and measured apparent diffusion coefficient （ADC） values in anatomical regions of normal prostate. Twenty-four healthy volunteers （mean age： 32 y） were studied by using a 1.5T system with a phased array surface multicoil. Two kinds of single-shot SE-EPI sequence were used to perform DWI in the prostate in volunteers, with five b values being 0, 30, 300, 500 to 1000 s/mm2. The image quality with different imaging parameters was analyzed and the ADC values in anatomical regions of normal prostate were measured. DWI of prostate was successfully obtained in all volunteers. The images were of good quality, without artifacts containing pixels within the prostate. The contrast was good between the different anatomical regions of the prostatic gland, i.e., the peripheral zone （PZ）, which exhibited higher signal intensity, and the central gland （CG）. Signal intensity contrast was related to the magnitude of b values. The ADC values in PZ and CG were （1.27±0.22）×10-3 mm2/s and （1.01±0.17）×10-3 mm2/s,respectively. The ADC values were found to be significantly higher in PZ than in CG （P〈0.05, paired t-test）. Significant differences were found between the slice-selecting component and both the read-out and phase-encoding components of the ADC values. It is concluded that SE-EPI is a suitable DWI sequence for human prostate. The contrast between PZ and CG is good when b values are low, while the diffusion and ADC values are accurate when b values are high. ADC values are higher in PZ than in CG in normal prostate. Diffusional anisotropy is present in normal prostatic tissue.

Optimal b value of diffusion-weighted imaging on a 3.0T magnetic resonance scanner in Crohn's disease

AIM: To determine the optimal b value of diffusion-weighted imaging for detecting active inflammation in Crohn’s disease.

Evaluation of diffusion weighted imaging of magnetic resonance imaging in small focal hepatic lesions:a quantitative study in 56 cases

Diffusion-weighted imaging (DWI) as a new technique of magnetic resonance imaging (MRI) is used to detect focal hepatic lesions. This study was designed to evaluate the significance of DWI to differentiate focal hepatic lesions less than 3 cm in diameter by the quantitation of apparent diffusion coefficient (ADC) values. METHODS:DWI using 1.5T MRI scanner unit was performed with a spin-echo single-shot echo planar imaging (EPI) in 56 cases of small focal hepatic lesions, including hepatocellular carcinoma (11), hepatic metastatic tumor (15 ), hepatic cavernous hemangioma (14), and hepatic cyst (16).The ADC values of these lesions were calculated respectively. The ratios of the ADC values of lesion/liver in hepatocellular carcinomas and hepatic metastatic tumors were also estimated. RESULTS:The mean ADC values (mm2/s) were (0.93±0.06) ×10-3 in hepatocellular carcinomas, (1.09±0.18)×10-3 in hepatic metastatic tumors,(1.95±0.38)×10-3 in hepatic cavernous hemangiomas, and (3.18±0.33) ×10-3 in hepatic cysts. The ratios of ADC values of lesion/liver were 0.90±0.06 and 1.15±0.14 in hepatocellular carcinoma and hepatic metastatic tumors respectively, which were significantly different (P<0.05). CONCLUSION:The measurement of ADC values and the ratios of ADC values of lesion/liver are helpful in MR diagnosis and differentiation of focal hepatic lesions.

3.0T常规MRI联合多b值DWI在前列腺癌诊断中的价值

目的 探究3.0T常规MRI联合多b值弥散加权成像(diffusion weighted imaging,DWI)应用在前列腺癌诊断中的价值。方法 回顾性分析,依据穿刺或手术病理结果将患者分前列腺癌组(n=32)与前列腺增生组(n=33),所有患者行3.0T常规MRI、常规MRI+多b值DWI检查(b值分别为1000s·mm^(-2)、2000s·mm^(-2)与3000s·mm^(-2)),计算两种检查的诊断准确率、特异度和敏感度并进行比较,不同b值DWI检查中前列腺增生组及前列腺癌组ADC值的比较,前列腺癌组癌灶与对侧或周围正常组织不同b值DW I信号强度差值、DWI信号强度对比度比较,以及不同b值DWI检查中癌灶ADC值比较。结果3.0T常规MRI+多b值DWI检查准确率、特异度和敏感度均显著高于常规M RI检查技术,(P<0.05);不同b值DWI检查中前列腺增生组的ADC值均高于前列腺癌组,差异有统计学意义(P<0.05);不同b值前列腺癌组与对侧正常组织DWI信号强度差值、DWI信号强度对比度有显著差别(P<0.05),随着b值升高DWI信号强度差值减小、DWI对比度升高;不同b值检查中癌灶的ADC值有显著差异(P<0.05),随着b值升高ADC值下降。结论 3.0T MRI多b值DWI联合应用技术有助于前列腺癌及增生的鉴别诊断,具有较高临床实用价值。

MRI多b值DWI成像对慢性肾病患者分期的评估价值研究

目的 探讨核磁共振(MRI)多b值弥散加权(DWI)成像对慢性肾病患者分期的评估价值。方法纳入2018年10月至2019年10月我院90例临床确诊的糖尿病肾病(DN)患者为观察组,以及同时期90例健康志愿者作为对照组,参照相关分期标准,将观察组患者分为DN早期组(54例)、DN中晚期组(36例),对比b值分别为50、300、500、800s/mm^(2)下DN中晚期组、DN早期组、对照组肾皮质ADC值,并分析观察组不同b值下ADC值与肾小球滤过率(GFR)相关性。结果 b值取50、100s/mm^(2)时,DN中晚期组肾皮质ADC值低于DN早期组与正常对照组(P<0.05),DN早期组与对照组肾皮质ADC值差异无统计学意义(P>0.05);b值取500、800s/mm^(2)时,正常对照组、DN早期组、DN中晚期组肾皮质ADC值呈下降趋势(P<0.05);观察组肾皮质ADC值与GFR呈正相关(b值取值50、300、500、800s/mm^(2)时,r分别为0.649、0.624、0.568、0.577,P均<0.05)。结论 MRI多b值DWI成像在DN的分期及肾功能状态的定量评估中具有一定应用价值,可作为一种无创性的肾功能评估手段。

3.0T磁共振多b值全身类PET成像对多发性骨髓瘤的应用研究

目的探讨研究多发性骨髓瘤(multiple myeloma,MM)在多个b值下的类PET表现特点;比较MM在不同b值下的类PET表现差异性;选取较好的b值。方法对19例经骨髓穿刺或临床综合资料确诊的MM患者采用Siemens3.0T磁共振进行全身类PET检查,b值分别选取50s/mm2、400s/mm2、700s/mm2,观察MM在不同b值下的类PET表现并进行对照研究。结果 MM病灶信号与正常椎间盘信号存在差异性,b值为700s/mm2时MM病灶为稍低信号,图像信噪比及对比噪声比降低,但对MM病灶检测敏感性增高,单因素方差分析P<0.05,认为MM病灶和正常椎间盘在三组不同b值下的类PET信号强度差别以及信噪比和对比噪声比差别有统计学意义。结论 MM的多b值类PET检查,700s/mm2为较好的b值,其可以提高MM病灶检测的敏感性。

多b值弥散加权成像对宫颈癌病理学特征及术前分期的诊断价值研究

目的研究多b值弥散加权成像(DWI)对宫颈癌病理学特征及术前分期的诊断价值。方法选取经病理确诊的宫颈癌患者87例为研究对象,均行1. 5T MR常规序列及多b值DWI扫描,记录宫颈癌区、非癌区(结合带、肌层)的多b值DWI参数值[双指数衰减模型计算慢速表观扩散系数(ADC_(slow))、快速表观扩散系数(ADCfast)、快速弥散所占容积分数(F_(fast))],并分析各参数与宫颈癌病理学特征的关系及对术前分期的诊断价值。结果宫颈癌区ADC_(slow)、ADC_(fast)、F_(fast)低于结合带非癌区、肌层非癌区(P <0. 05),结合带、肌层非癌区上述指标对比差异无统计学意义(P>0. 05)。鳞癌ADC_(slow)低于腺癌,而ADC_(fast)、F_(fast)高于腺癌(P <0. 05);随分化程度增加,ADC_(slow)增加(P <0. 05),而ADC_(fast)、F_(fast)无明显变化(P>0. 05);不同肿瘤直径、有无淋巴结转移患者多b值DWI参数值比较差异无统计学意义(P> 0. 05)。不同术前分期患者ADC_(slow)比较差异有统计学意义(P <0. 05)。结论多b值DWI与宫颈癌患者病理类型、分化程度等病理学特征存在一定关系,同时可用于指导术前分期,值得在临床推广应用。

运用多b值DWI探讨前列腺中央腺体癌的诊断

目的运用3.0 T MR多b值DWI探讨b值选择对前列腺中央腺体癌(CGPCa)及良性前列腺增生(BPH)鉴别效能的影响。方法经病理证实的28例CGPCa及23例BPH患者行常规序列及DWI序列扫描,DWI设定4个b值(0、500、1000、1500 s/mm^2),分别选取b=0、1000 s/mm^2,b=0、500、1000 s/mm^2,b=0、1500 s/mm^2,b=0、500、1500 s/mm^2,b=0、1000、1500 s/mm^2,b=0、500、1000、1500 s/mm^2拟合得到ADC图,测量感兴趣区域(ROI)的ADC值。采用两独立样本t检验比较CGPCa组与BPH组ADC值的差异,应用受试者工作特征(ROC)曲线评价不同b值组合的诊断效能。结果 b=0、1000 s/mm^2和b=0、500、1000 s/mm^2两组在CGPCa及BPH组各ROI的ADC值均相等。CGPCa及BPH组在不同b值组合下ADC值差异均有显著统计学意义(P<0.001)。b=0、1000 s/mm^2,b=0、500、1000 s/mm^2,b=0、1500 s/mm^2,b=0、500、1500 s/mm^2,b=0、1000、1500 s/mm^2,b=0、500、1000、1500 s/mm^2的曲线下面积(AUC)分别为0.912、0.912、0.952、0.950、0.952、0.950;两两比较显示b=0、1500s/mm^2,b=0、1000、1500 s/mm^2,b=0、500、1000、1500 s/mm^2三组分别与b=0、1000 s/mm^2和b=0、500、1000 s/mm^2组的AUC比较差异有统计学意义,P值分别为0.015、0.009、0.015。在b=0、1500 s/mm^2组,当ADC值阈值为0.901×10^(-3)mm^2/s时,诊断CGPCa的敏感性为92.86%,特异性为100%,阳性预测值为100%,阴性预测值为85.2%。结论 b=1500 s/mm^2的高b值DWI对于鉴别CGPCa与BPH具有显著意义,诊断效能优于b=1000 s/mm^2的常规DWI。