基于心电门控技术对肝脏体素内不相干运动成像的应用研究

发布时间：2018-03-14 16:33

  本文选题：体素内不相干运动　切入点：扩散加权成像　出处：《广州中医药大学》2017年硕士论文　论文类型：学位论文

【摘要】：目的:评价心电门控(electrocardiograph-triggered)技术对肝脏体素内不相干运动成像(magnetic resonance diffusion-weighted intravoxel incoherent motion imaging,IVIM-DWI)图像质量、表观扩散系数(apparent diffusion coefficient,ADC)及IVIM相关参数测量值大小及其可重复性的影响;同时在此基础上研究基于心电门控的IVIM-DWI技术在临床肝脏病变中的诊断价值。方法:实验一:选择2015年5月至2015年12月期间符合条件的116名接受心电门控IVIM-DWI 序列扫描的志愿者,设定 6 个 b 值(b=0,50,100,150,300,600s/mm2),按受检者心率分为2组,低心率组受检者心率≤70次/分,高心率组受检者心率≥80次/分。采用单指数线性函数模型和双指数非线性模型对扫描所得全肝IVIM-DWI图像进行拟合得到平均ADC图,以及D值、D*值和f值伪彩参数图。选取其中连续3层作为R0I放置层面,在所选层面肝左、右叶各放置3个100mm2的圆形R0I,共各取9个R0I的平均值代表左、右肝的ADC值、D值、D*值和f值,并进行统计分析。实验二:选择2016年5月至2016年6月期间符合条件的18名中青年健康志愿者,每位志愿者行两次腹部IVIM-DWI检查,扫描过程中采用自由呼吸、自由呼吸结合心电门控两种技术采集5层肝脏IVIM-DWI图像,b值取0,50,100,150,300,600s/mm2。每个序列选择中间三层图像,分别在肝左、右叶实质、腹壁外各放置3个100 mm2的圆形R0I进行图像分析,获得相应的肝脏信号强度(signal intensity,SI)、信号噪声(standard deviation,SD),计算SNR值。同实验一的方法获取肝脏平均ADC值、D值、D*值和f值。两次测量的一致性评价采用配对t检验、pearson相关系数及组内相关系数ICC进行分析。两次扫描获得的ADC、D、D*和f测量值的一致性采用Bland-Altman方法评价。对两种技术中肝左、右叶平均SNR值、ADC值、D值、D*值和f值进行统计分析。实验三:收集2016年6月至2016年12月在我院诊断肝脏局灶性病变并行上腹部IVIM-DWI检查的66例患者(共85个病灶),所有患者于治疗前行常规上腹部MR扫描及IVIM-DWI扫描,扫描采用自由呼吸、自由呼吸结合心电门控两种技术,b值取0,50,100,150,300,600s/mm2。分别在肝左、右叶实质、病灶、腹壁外各放置3个100 mm2的圆形R0I进行图像分析,计算SNR、CNR值。将R0I放置于病灶最大层面,获得病灶平均ADC值、D值、D*值和f值。采用配对t检验比较自由呼吸和自由呼吸结合心电门控良恶性组间各b值的SNR、CNR及拟合所得ADC、D、D*、f值。结果:实验一:(1)低心率组和高心率组所得肝左叶ADC值、D值、f值高于肝右叶,均具有显著性差异(P0.05)。(2)低心率组肝左叶的平均ADC值、D值、f值均低于高心率组,差异有统计学意义(P0.01)。(3)低心率组肝右叶的平均ADC值、f值低于高心率组,差异具有统计学意义(P0.05)实验二:(1)自由呼吸结合心电门控序列肝左、右叶SNR值均高于自由呼吸,差异有统计学意义(P0.05)。(2)两次测量的ICC范围,肝左、右叶ADC、D、f值均具有较好的一致性(左叶:0.869至0.987;右叶:0.776至0.980)。肝左、右叶D*值一致性较差(左叶:0.153 至 0.846;右叶:0.312 至 0.574)。(3)自由呼吸结合心电门控技术肝左叶ADC、D、f值两次扫描测量值的可重复性好于自由呼吸,其中f值的可重复性最好(L0A为0.03%),D*值两次扫描测量值的可重复性较自由呼吸差(L0A为20.95%)。自由呼吸结合心电门控技术肝右叶ADC、D*、f值两次扫描测量值的可重复性较自由呼吸差,D*值的可重复性最差(L0A为14.75%);f值两次扫描测量值的可重复性好于自由呼吸(L0A为0.03%)。IVIM-DWI参数值中,D*值的可重复性最差。(4)两种采集技术肝左叶ADC、D值均大于肝右叶(P0.01);肝左叶D*值小于肝右叶(P0.01);肝左叶f值大于肝右叶,仅在自由呼吸条件下差异有统计学意义(P0.01)。(5)自由呼吸结合心电门控技术肝左、右叶的ADC、D、D*、f值低于自由呼吸,其中肝左叶间D*值差异不明显(P=0.464),ADC值、D值、f值差异均有统计学意义(P0.05);肝右叶间D值(P=0.781)、D*值(P=0.161)间差异不明显,ADC值f值(P0.01)差异均有统计学意义。实验三:(1)自由呼吸结合心电门控心电门控技术获得的肝脏IVIM-DWI图像信噪比、对比噪声比均高于自由呼吸(P0.01)。(2)两种技术采集条件下肝脏良性病变的ADC值及IVIM参数值均高于肝脏恶性病变,差异具有统计学意义(P0.05)。(3)自由呼吸结合心电门控技术肝脏良、恶性病ADC值及IVIM参数值低于自由呼吸,两者间仅恶性病变D*差异不显著(P=0.073)。结论:(1)适当的控制和降低心率,可减少肝脏IVIM-DWI图像运动伪影,从而获得相对准确的参数值,尤其是在肝左叶。(2)在肝脏IVIM-DWI成像时采用自由呼吸结合心电门控技术可明显改善肝脏图像质量、提高图像信噪比,尤其当心率控制在70bmp以下时,肝脏图像信噪比高、病灶显示清晰,图像质量好。(3)自由呼吸结合心电门控技术对ADC值及IVIM相关参数大小及可重复性有一定影响,肝左叶效果更明显,稳定性更好。(4)ADC、D、D*、f值可用于肝脏良恶性病变的鉴别,但D*可重复性差,具有较高的测量误差,建议临床运用时应慎重。
[Abstract]:Objective: To evaluate the ECG gating (electrocardiograph-triggered) technique on liver intravoxel incoherent motion imaging (magnetic resonance diffusion-weighted intravoxel incoherent motion imaging, IVIM-DWI) image quality, apparent diffusion coefficient (apparent diffusion, coefficient, ADC) and IVIM related parameters can affect the size and repeatability; at the same time on the basis of the research on the value of ECG gated IVIM-DWI technology in clinical diagnosis of liver diseases. Methods: Based on experiment one: during the period of May 2015 to December 2015 with 116 patients who received cardiac gated IVIM-DWI sequence scanning a set of volunteers, 6 B (b=0,50100150300600s/mm2), heart rate in subjects were divided into 2 groups, low heart rate group subjects the heart rate less than 70 BPM, high heart rate group subjects heart rate is greater than or equal to 80 beats per minute. Using the single index model and double linear function index The linear model is fitted by average ADC of scanning the whole liver IVIM-DWI images, and the D value, D* value and F value of pseudo color parameters. Select one of 3 consecutive layers as R0I placed in the selected level, level of left hepatic right lobe, each placed 3 100mm2 circular R0I, a total of 9 R0I each the average left, right hepatic ADC value, D value, D* value and F value, and statistical analysis. Experiment two: 18 young healthy volunteers during May 2016 to June 2016 in line with the conditions, each volunteer underwent two abdominal IVIM-DWI examination, the scanning process by free breathing, breath free combination two kinds of ECG gating technology to collect 5 liver IVIM-DWI images, b values of each 0,50100150300600s/mm2. sequence selection between the three layers of the image, respectively in the left hepatic parenchyma, and the abdominal wall and the 3 placed 100 mm2 circular R0I image analysis, get the corresponding strong liver signal Degree (signal intensity, SI), signal to noise (standard deviation, SD), the calculation of SNR value. The same way as the experimental one gets the average liver ADC value, D value, D* value and F value. The consistency of the evaluation of two measurements using paired t test, Pearson correlation coefficient and intraclass correlation coefficient ICC analysis. Two scan obtained ADC, D, evaluation method using Bland-Altman D* consistency and F values. The two kinds of technology in the right lobe of the left liver, the average SNR value, ADC value, D value, D* value and F value were analyzed. Experiment three: 66 cases collected from June 2016 to December 2016 in our hospital the diagnosis of focal liver lesions on parallel abdominal IVIM-DWI examination patients (85 lesions), all patients underwent conventional abdominal MR scanning and IVIM-DWI scanning, the freedom to breathe, breathe freely with ECG gated two techniques, B = 0,50100150300600s/mm2. respectively in the left hepatic lobe,. 璐，

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