【作者】 孟祥水；

【导师】 马祥兴；

【作者基本信息】 山东大学 ， 影像医学与核医学（专业学位）， 2014， 博士

【摘要】 前言常规影像学检查(如CT、MRI)阴性的脑动脉闭塞或狭窄的脑血管病与脑卒中、白质疏松、脑萎缩、血管性痴呆有明显关系,采用有效的无创检查方法评价狭窄或闭塞动脉供血区脑组织的缺血损害程度尤为重要。本研究拟采用3.0T磁共振PWI、DTI及MRS研究常规影像学检查阴性的脑动脉闭塞或重度狭窄患者的脑组织血流灌注、弥散及代谢改变,为临床提供有效诊断信息。研究分为三部分,第一部分：3.0T磁共振PWI在单侧大脑中动脉闭塞的应用；第二部分：3.OT磁共振DTI在单侧大脑中动脉闭塞的应用；第三部分3.0T磁共振MRS在单侧大脑中动脉闭塞的应用。第一部分3.0T磁共振PWI在单侧大脑中动脉闭塞中的应用摘要目的：利用3.0T磁共振PWI对常规MRI脑实质无异常信号的单侧大脑中动脉闭塞或重度狭窄患者进行研究,以评价其供血区脑组织及远端脑白质灌注改变。方法：采用GE EXCITE Ⅱ3. OT双梯度超导磁共振仪,对脑实质无异常信号的34例单侧大脑中动脉M1段闭塞或重度狭窄(≧75%)患者进行PWI研究,PWI采用T2*梯度回波EPI (T2*-GRE-EPI)成像序列,采用正交头线圈,扫描范围包括全脑,对比剂采用马根维显(Gd-DTPA),注射剂量0.2mmol/kg,流速4m1/s。采用GE functool4.2软件对受检者灌注数据进行后处理,对患、健侧放射冠区、颞叶皮质、丘脑、豆状核、内囊前肢、内囊后肢、大脑脚rCBF、rCBV、MTT、TTP进行分析,统计学方法利用SPSS13.0软件,采用配对t检验或秩和检验方法,按α=0.05水准,P<O.05为差异具有统计学意义。结果：患侧放射冠区较镜像健侧平均MTT及TTP延长(P<0.01),平均rCBF降低(P<0.01),平均rCBV无统计学差异；患侧颞叶皮质较健侧镜像区平均MTT及TTP延长(P<0.01),平均rCBF、rCBV无统计学差异；患侧豆状核较健侧镜像区平均TTP延长(P<0.01),平均MTT、rCBF、rCBV无统计学差异；患侧内囊前肢及后肢较镜像健侧区平均TTP延长(P<0.01),平均MTT、rCBF及rCBV无统计学差异；患侧丘脑、大脑脚MTT、rCBF、rCBV及TTP较镜像健侧无统计学差异。结论：利用MTT、rCBF、rCBV及TTP可快速、无创地评价常规MRI脑实质无异常的脑动脉闭塞或重度狭窄供血区脑组织血流灌注异常改变,其供血区远端脑白质无灌注异常发生,其中以MTT及TTP两参数最为敏感。目的：利用3.0T磁共振DTI对常规MRI脑实质无异常信号的单侧大脑中动脉Ml段闭塞或重度狭窄患者进行研究,以评价供血区及其远端脑组织弥散改变。方法：采用GE EXCITE Ⅱ3.0T双梯度超导磁共振仪,对脑实质无异常信号的34例单侧大脑中动脉闭塞或重度狭窄(≧75%)患者进行DTI研究。DTI采用单次激励自旋回波EPI序列：(TR,6000ms;TE,90ms;NEX,4;thickness,5mm),扩散敏感梯度取15个方向,通过预实验b值取2200s/mm2。采用GE functool4.2软件对受检者DTI数据进行后处理,测量受检者患、健侧放射冠区、颞叶皮质、丘脑、豆状核、内囊前肢、内囊后肢、大脑脚及脑桥FA值、ADC值、平行弥散方向本征值λ1及垂直弥散方向本征值λ23。统计学方法利用SPSS13.0软件,采用配对t检验或秩和检验,按α=0.05水准,P<0.05为差异具有统计学意义。结果：患侧放射冠区较镜像健侧FA值减小(P<0.05),ADC、λ1及λ23值增大(P<0.05)；患侧颞叶皮质λ23值较健侧增大(P<0.05),而FA、ADC、λ1值无统计学差异；患侧豆状核较健侧λ23值增大(P<0.05),而患、健侧FA、ADC及λ1值无统计学差异；患侧内囊前肢及后肢较健侧FA值减小(P<0.05),λ23值增大(P<0.05),而ADC及λ1值与健侧无统计学差异。患、健侧丘脑、大脑脚及脑桥FA、ADC、λ1及λ23值无统计学差异。结论：采用高b值DTI能够敏感探测常规MRI无异常信号的慢性脑动脉闭塞或重度狭窄供血区脑组织弥散异常,而缺血区远端脑白质无弥散异常改变。目的：利用3.0T磁共振MRS对常规MRI脑实质无异常信号的单侧大脑中动脉闭塞或重度狭窄患者进行研究,以评价供血区脑组织代谢改变。方法：采用GE EXCITE Ⅱ3.0T双梯度超导磁共振仪,对脑实质无异常信号的34例单侧大脑中动脉M1段闭塞或重度狭窄(≧75%)患者进行MRS研究。MRS采用化学位移成像(Chemical Shift Imaging, CSI)进行多体素采集,点解析波谱(Point Resolved Spectroscopy, PRESS)序列扫描,TR1500ms, TE135ms,采集时间5.6min。应用GE EXCITE Ⅱ3.0T MR仪自带MRS分析软件,测量患、健侧放射冠区、丘脑、豆状核NAA、Cr、Cho及NAA/Cho、NAA/Cr、Cho/Cr值,并观察Lac峰。统计学方法利用SPSS13.0软件,采用配对t检验或秩和检验,按α=0.05水准,P<0.05为差异有统计学意义。结果：患侧放射冠区较镜像健侧平均NAA、Cr、NAA/Cr及NAA/Cho减小(P<0.01), Cho及Cho/Cr增大(P<0.05)；患侧丘脑平均Cho、NAA、Cr、NAA/Cr、 NAA/Cho及Cho/Cr与镜像健侧无统计学差异；患侧豆状核较镜像健侧平均NAA、NAA/Cho降低降低(P<0.05), Cho及Cho/Cr升高(P<0.05),患侧豆状核Cr及NAA/Cr与镜像健侧无统计学差异,所有患者患侧各测量部位未观察到Lac峰。结论：MRS可敏感检测慢性脑动脉重度狭窄或闭塞所致供血区脑组织的代谢改变,弥补了常规MRI的不足。更多还原

【Abstract】 Patient with occlusion or severe stenosis of the cerebral artery without MRI evidence of brain parenchymal abnormalities is prone to suffer cerebral stroke, leukoaraiosis, encephalanalosis, vascular dementia. It is important to evaluate the damage of patient’s brain parenchymal with non-invasive imaging methods. In our study, the patients with normal appearing brain parenchymal and occlusion or severe stenosis of the unilateral middle cerebral artery (MCA) area were performed with perfusion-weighted imaging(PWI), diffusion tensor imaging (DTI) and magnetic resonance spectrum(MRS) use of a3T Tesla scanner(Ge Medical System, Excite Ⅱ,USA). The study was divided three chapter:CHAPTER Ⅰ application of perfusion-weighted imaging in unilateral cerebral arterial occlusive disease using3. OT MR, CHAPTER Ⅱ application of diffusion tensor imaging in unilateral cerebral arterial occlusive disease using3. OT MR, CHAPTER Ⅲ application of magnetic resonance spectrum in unilateral cerebral arterial occlusive disease using3.0T MR.CHAPTER Ⅰ Application of Perfusion-weighted Imaging in Unilateral Cerebral Arterial Occlusive Disease using3.0T MRABSTRACTPurpose:To assess perfusion changes in the areas brain parenchymal and remote white matter with unilateral occlusion or severe stenosis of the MCA without magnetic resonance imaging (MRI) evidence of brain parenchymal abnormalities using PWI.Materials and Methods:A total of34patients with occlusion or severe unilateral stenosis (≥75%) of the MCA without abnormal brain parenchymal signals underwent PWI at3T MR. The protocol was axial PWI with T2*-GRE-EPI. All brain imaging was conducted using a quadrature birdcage head coil. Contrast was Gd-DTPA with the dose of0.2mmol/kg and the rate of flow of4mml/s. PWI data were transferred to a workstation supplied by the manufacturer (Advantage Workstation4.2; GE Health-care) for further analysis. rCBF, rCBV, MTT and TTP were measured at ipsilateral (affected hemisphere) and contralateral (unaffected hemisphere) corona radiata, gray matter of temporal lobe, thalamus, lentiform nucleus, anterior and posterior limbs of the internal capsule and cerebral peduncle on the T2WI for all patients. Data analysis was conducted using SPSS13.0(SPSS, Chicago, IL, USA). Paired t-tests and rank test were used to compare mean rCBF, rCBV, MTT and TTP values. P<0.05was considered statistically significant.Results:The mean MTT and TTP were significantly higher, mean rCBF was significantly lower at ipsilateral corona radiata than at contralateral corona radiata (P<0.01), mean rCBV was not significantly different between the bilateral corona radiata. The mean MTT and TTP were significantly higher at gray matter of ipsilateral temporal lobe than at contralateral temporal lobe (P<0.01), mean rCBF and rCBV were not significantly different between the bilateral temporal lobe. The mean TTP was significantly higher at ipsilateral lentiform nucleus than at contralateral lentiform nucleus (P<0.01), mean MTT, rCBF and rCBV were not significantly different between the bilateral lentiform nucleus. The mean TTP was significantly higher at ipsilateral anterior and posterior limbs of the internal capsule than at contralateral anterior and posterior limbs of the internal capsule (P<0.01), mean MTT, rCBF and rCBV were not significantly different between the bilateral anterior and posterior limbs of the internal capsule. Mean MTT, rCBF, rCBV and TTP were not significantly different between the bilateral thalamus and bilateral cerebral peduncle.Conclusion:In conclusion, MTT, rCBF, rCBV and TTP may be used to sensitively depict perfusion changes in the brain parenchymal of regions of cerebral artery obstruction without abnormal perfusion in the remote white matter in patients with occlusion or severe stenosis of the MCA without MRI evidence of brain parenchymal abnormalities. Purpose:To assess diffusion changes in the brain parenchymal and remote brain parenchymal with unilateral severe stenosis or occlusion of the MCA without MRI evidence of brain parenchymal abnormalities using high b-value DTI.Materials and Methods:A total of34patients with severe occlusion or unilateral stenosis (≥75%) of the MCA without abnormal brain parenchymal signals underwent DTI at3.0T MR.The protocol was axial sensitivity-encoding echo-planar DTI with high b values (6000ms TR,90ms TE, four excitations),5mm section thickness,15non-collinear gradient directions; b=2200s/mm2. DTI data were transferred to a workstation supplied by the manufacturer (Advantage Workstation4.2; GE Health-care) for further analysis. FA, ADC, λ1and λ23were measured at ipsilateral (affected hemisphere) and contralateral (unaffected hemisphere) corona radiata, gray matter of frontal lobe, thalamus, lentiform nucleus, anterior and posterior limbs of the internal capsule, cerebral peduncle and pons on the T2WI (b=0) for all patients. Data analysis was conducted using SPSS13.0(SPSS, Chicago,IL, USA). Paired t-tests and rank test were used to compare mean FA, ADC, λ1and λ23values. P<0.05was considered statistically significant.Results:The mean FA was significantly lower (P<0.05), mean ADC, λ1and λ were significantly higher at ipsilateral corona radiata than at contralateral corona radiata (P<0.05).The mean λ23was significantly higher at ipsilateral gray matter of frontal lobe and lentiform nucleus than at contralateral frontal lobe and lentiform nucleus (P<0.05), mean FA,ADC and λ1were not significantly different between the bilateral gray matter of frontal lobe and bilateral lentiform nucleus. The mean FA was significantly lower, mean λ23was significantly higher at ipsilateral anterior and posterior limbs of the internal capsule than at contralateral anterior and posterior limbs of the internal capsule (P <0.05), mean ADC and λ1were not significantly different between the bilateral anterior and posterior limbs of the internal capsule. Mean FA, ADC, λ1and λ23were not significantly different between the bilateral thalamus, bilateral cerebral peduncle and bilateral pons.Conclusion:In conclusion, DTI may be used to sensitively depict diffusion changes in the brain parenchymal of regions of cerebral artery obstruction without abnormal anisotropy and diffusivity in the remote white matter in patients with occlusion or severe stenosis occlusion of the MCA without MRI evidence of brain parenchymal abnormalities. Purpose:To assess metabolism changes in the areas brain parenchymal with unilateral occlusion or severe stenosis of the MCA without MRI evidence of brain parenchymal abnormalities using MRS.Materals and Methods:A total of34patients with occlusion or severe unilateral stenosis (≥75%) of the MCA without abnormal brain parenchymal signals underwent MRS at3.0T MR. The protocol was chemical shift imaging (CSI) MRS with multi voxel acquisition and point resolved spectroscopy (PRESS)(1500ms TR,135ms TE),5mm section thickness,5.6min scan time. MRS data were transferred to a workstation supplied by the manufacturer (Advantage Workstation4.2; GE Health-care) for further analysis. NAA, Cr, Cho, NAA/Cho, NAA/Cr, Cho/Cr and were Lac measured at ipsilateral (affected hemisphere) and contralateral (unaffected hemisphere) corona radiata, thalamus and lentiform nucleus on the T2WI for all patients. Data analysis was conducted using SPSS13.0(SPSS, Chicago, IL, USA). Paired t-tests and rank test were used to compare NAA, Cr, Cho, NAA/Cho, NAA/Cr and Cho/Cr. P<0.05was considered statistically significant.Results:The mean NAA, Cr, NAA/Cr and NAA/Cho were significantly lower, mean Cho, Cho/Cr were significantly higher at ipsilateral corona radiata than at contralateral corona radiata (P<0.05). Mean Cho, NAA, Cr, NAA/Cr, NAA/Cho and Cho/Cr were not significantly different between the bilateral thalamus. The mean NAA and NAA/Cho were significantly lower, mean Cho and Cho/Cr were significantly higher at ipsilateral lentiform nucleus than at contralateral lentiform nucleus (P<0.05),while Cr and NAA/Cr were not significantly different between the bilateral lentiform nucleus, Lac was not found at ipsilateral corona radiata, thalamus and lentiform nucleus of these patients.Conclusion:In conclusion, MRS may be used to sensitively depict metabolism changes in the brain parenchymal of regions of cerebral artery obstruction in patients with occlusion or severe stenosis of the MCA without MRI evidence of brain parenchymal abnormalities.更多还原