【作者】 李跃华；

【导师】 陆建平；

【作者基本信息】 第二军医大学 ， 影像医学与核医学， 2008， 博士

【摘要】 第一部分小血管MR成像序列改进的实验性研究目的对小血管磁共振血管成像（MRA）序列及各项参数设置包括重复时间（TR）,回波时间（TE）,接受带宽（Bandwidth）,翻转角度（FA）,K空间填充方式等进行理论与实验研究;设置最佳的造影剂注射参数（包括造影剂的注射用量、注射速率、延迟时间等）,从而获得最佳的血管成像图像,为下一步研究奠定基础。材料与方法实验性研究中应用管径6.0mm至0.13mm的无磁性细管,管内注满稀释造影剂（15mmol/L）,置于特定背景组织内（1%蛋白胨营养琼脂内）进行成像研究;临床研究主要为10名健康志愿者随机分为2组,每组5名,分4次进行MR扫描,每次采用0.3ml/s,1.0ml/s,2.0ml/s,3.0ml/s不同速率注射造影剂,组Ⅰ注射剂量为单倍剂量15ml,组Ⅱ注射剂量为双倍剂量30ml。分别测量主动脉、门静脉及下腔静脉内的峰值时间、持续时间以及信号强度。结果直径为6.0-0.51mm的细管显示清晰,而0.25mm,0.18mm,0.13mm的细管显示不清。在其它参数相对固定情况下,翻转角确定在20-25°,信噪比最高,所得到的图像质量最佳;相位编码与FOV相对其它参数对成像时间及图像质量的影响大。单倍剂量与双倍剂量注射对主动脉内信号强度峰值的增加无明显统计学意义。当注射速率大于1ml/s时增加注射速率对主动脉内的信号强度增加的意义不大,峰值到达时间无明显缩短;在静脉的测试中,峰值时间与注射速率无明显关系。当注射速率达到3ml/s时,主动脉的SNR有明显的增加,但是门静脉和下腔静脉的SNR无明显改变。结论理论值上得出3D-SPGR序列对小血管的分辨率极限为0.5mm,序列主要参数的确定在根据靶血管形状的基础上遵循以下几点1.利用TR、TE设置预期对比度;2.在动脉时相的时间要求内设置相位编码及采集次数;3.以层厚、间距和FOV为主要调节手段提高图像的质量。造影剂注射采用3ml/s,注射量为0.2mmol/Kg,可以获得主动脉内最佳的信噪比,同时静脉的影响可以降低到最低限度。第二部分Adamkiewicz动脉的MR血管成像目的前瞻性研究对比剂增强MR血管成像（CE-MRA）显示Adamkiewicz动脉的可行性,在外科术前对脊髓血管进行评估,为脊柱外科的诊断与治疗提供参考。材料与方法10名志愿者及15例胸腰段椎间盘突出的术前患者行MR血管增强扫描。在常规扫描序列完成后,进行MRA扫描,扫描序列采用采用三维扰相梯度回波序列（3D-SPGR）序列,扫描范围包括胸腹主动脉及其分支。注射对比剂量为0.2mmol/kg。K空间填充方式为椭圆中心填充。MRA图像在工作站经过最大信号强度投影（MIP）及曲面重建（Reformat）件处理后显示Adamkiewicz动脉。结果在所有的25例检查中,造影剂到达靶血管的峰值时间为12～18 s。脊髓前正中动脉（ASA）、Adamkiewicz及节段动脉显示良好,所有病例的Adamkiewicz动脉均起源于T8～L2之间。其中起源于左侧20例,右侧5例。ASA显示的范围T6～L3不等。Adamkiewicz的直径为0.6～1.2 mm,ASA直径为0.6～1.0 mm。结论CE-MRA扫描能对Adamkiewicz动脉进行准确的定位并能够提供可靠的信息,对临床有一定的价值。第三部分腰动脉供血状况与相应平面椎间盘ADC值测量的关系目的通过MR对腰动脉成像以及腰椎间盘ADC值的测量了解腰动脉供血情况与所在平面椎间盘ADC之间的关系,为下腰痛患者及椎间盘退变患者提供诊治信息。材料与方法65名主要怀疑腰椎病变的患者及10名志愿者接受检查,65例行腰动脉MRA成像,年龄16-76岁,平均年龄52.3岁。其中下腰痛并坐骨神经痛11人,下腰痛无坐骨神经通者16人,坐骨神经痛无下腰痛33人,跛行5人。检查时间与症状发现间隔为1-57周,平均13.4周。10名正常志愿者接受腰骶部MRA成像,年龄22-43岁,平均29.4岁;无明显腰痛病史。结果L1-4平面腰动脉及腰骶动脉的MRA图像显示良好。椎间盘退变程度的分级与ADC值测量结果存在统计学意义（P＜0.05）,即退变程度越大的椎间盘其ADC值越小;L1、L2、L3平面的腰动脉情况分别与所在平面的L1-2、L2-3、L3-4椎间盘退变情况存在很高的相关性(F_L1-L2=25.982,P_L1-L2=0.017＜0.05;F_L2-L3=23.173,P_L2-L3=0.017＜0.05:F_L3-L4=20.552,P_L3-L4=0.026＜0.05),而L4腰动脉与L4-5椎间盘退变情况无明显相关性(F_L4-L5=10.982,P_L4-L5=0.125＞0.05)。结论L1-2、L2-3、L3-4椎间盘ADC值能够反映所在平面腰动脉供血情况。L4-5椎间盘所供养的腰4动脉与腰骶动脉存在广泛的交通,故其退变情况与腰4动脉无明显相关性。更多还原

【Abstract】 PartⅠStudy of improvement on MRA of small artery’s techniquesObject To study MRA of small vessel’s techniques including repeat time（TR）,echo time（TE）,receive bandwith（Bandwith）,flip angle（FA）,K-space type and adjust the best way of injection of contrast material（including the total dose,injection’s speed and the delay time）.Getting the best imaging of small vessel for the next stepMaterial and methods We placed the small vessel without magnetic which diameters 6.0mm-0.13mm filled with the contrast material（15mmol/L） on the special tissue（1%protein agar） in order to show it on magnetic resonance imaging;10 healthy volunteers was engaged in clinical study and parted in two groups randomly and one group contents 5 volunteers.4 MR scanning was proceeded in every volunteer and the injection’s speed was 0.3ml/s,1.0ml/s,2.0ml/s,3.0ml/s respectively.The dose of GroupⅠwas 15ml, the dose of groupⅡwas 30ml.In scanning the peak enhancement and duration time of aorta,portal vein,inferior caval vein was measured.Result Small vessel which the diameter from 6.0mm to 0.51mm was shown clearly.SNR was the highest and the imaging was best when flip angle in 20-25 under the condition of other parameter was fixed.Phase and FOV was more effect than other parameter on total time and imaging qualities.There was no significant statistics means on enhancement of aorta’s peak between the single dose and the double dose.When the speed was higher than 1ml/s,there was no significant enhancement on aorta and peak time was no more short.In the test of vein,there was no relation between the peak time and injection speed when the speed was more higher than 1ml/s.Enhancement peak on aorta was increased,however SNR of portal vein and inferior caval vein was not changed.Conclusion In 3D-SPGR technique the resolution was 0.5mm.Parameter was confirmed by 3 ways based on target small vessel.1.contrast should be depend on TR and TE times.2.phase and NEX was set in aortal time phase.3.slice thickness,slip and FOV was the important role to adjust the quality of imaging.When the injection speed was 3ml/s and the dose was 0.2mmol/kg,the SNR of aorta was best and influence of vein was the smallest.PartⅡMR angiography of Adamkiewicz arteryObjective To prospectively investigate the feasibility of contrast material-enhanced magnetic resonance angiography（CE-MRA） for visualization of the spinal vasculature and to assess the spinal vasculature for diagnosis and treatment of spinal surgery.Methods Ten volunteers and fifteen patients with a thoracic herniated disk or lumbar herniated disk underwent contrast-enhanced MR angiography of the thoracoabdominal aorta and posterior branches.Examination was performed with three-dimensional contrast-enhanced MR angiographic technique and 0.3 mmol/kg of gadolinium contrast agent.K-space was ellipse padding.Imaging of MRA was processed by software of maxium intensity projection（MIP） and Reformat.Result In all examinations,time which contrast reached the target vessel was 12-18 seconds The Adamkiewicz,the ASA,and the connection with the aorta were identified. The Adamkiewicz originated between T9 and L2 in all examination and derived from the left side of the aorta in 80%of all examination.ASA was observed from T6 to L2.The diameter of Adamkiewicz was 0.6-1.2mm and ASA was 0.6-1.0mm.Conclusion Contrast-enhanced MR angiography can be used to localize Adamkiewicz and provide accurate information for clinical approach. PartⅢCorrelation Between Diffusion in Lumbar Intervertebral Disks and Lumbar Artery StatusObjective To evaluate the correlation of the lumbar artery status with the diffusion values in lumbar vertebral disks in patients with low back problems using MRA technique and provide helpful information for diagnosis and treatment.Material and methods MR angiography in evaluating the status of lumbar arteries was calculated.Then,The sagittal diffusion-weighted MRimages in 260 intervertebral disks（L1-2 to L4-5） and MR angiographic images in the corresponding 260 lumbar artery pairs（total of 520 arteries） of the 65 patients with low back problems.65 patients.（39 men,26 women;mean age 52.3 years;age range 16-76 years） were included in the present study.Low back pain with sciatica was found in 11, low back pain without sciatica in 16,sciatica without low back pain in 33,and intermittent claudication in five patients.The time interval from onset of clinical symptoms to MR examination was 1 - 57 weeks（mean 13.4 weeks）.10 volunteers was proceed MRA examination.（age range 22-43,mean age 29.4）.They were not been found with low back pain.Result lumbar artery of L 1-4 was well showed.There was statistics means between the degradation of lumbar disc and its ADC.（p＜0.05）.There was positive relation between artery status of L1,L2,L3 and lumbar disc of L1-2、L2-3、L3-4.(F_L1-L2=25.982,P _L1-L2=0.017＜0.05;F_L2-L3=23.173,P_L2-L3=0.017＜0.05;F_L3-L4=20.552,P _L3-L4=0.026＜0.05))However there was no positive relation between the artery of L4 and the L4-5 lumbar disc(F_L4-L5=10.982,P_L4-L5=0.125＞0.05).Conclusion ADC value of the L1-2、L2-3、L3-4 can reflect the status of the lumbar artery.There was no significant relation between the L4-5 lumbar disc and the L4 lumbar artery because of the L4 lumbar artery has many small vessel coincided with artery of iliolumbar.更多还原