脑梗死前期脑局部微循环障碍CT灌注成像的实验研究

目的 从微循环的角度探讨脑梗死前期CT灌注成像表现及其病理基础，以及星形细胞与脑局部微循环的关系。方法 建立大鼠脑局部低灌注模型和脑局部星形细胞水肿模型，在动态CT脑灌注成像检查后处死，分别作灌注CT参数图、红四氮唑(TTC)染色、电子显微镜(简称电镜)和光学显微镜(简称光镜)观察。脑局部低灌注模型作了局部脑血流量(regional cerebral blood flow，rCBF)、局部脑血容量(regional cerebral blood volume，rCBV)、平均通过时间(mean transit time，MTT)和最大峰值时间(time-to-peak，TTP)比值(病侧／健侧)测量。结果 大鼠脑局部低灌注模型实验组的rCBF和MTT参数图显示病变侧低灌注区，rCBV和TTP参数图未见异常。rCBF、rCBV、MTT和TTP的比值范围分别为：0．39～0．55、0．92～1．00、1．20～1．50和1．00～1．00。电镜见星形细胞水肿，肿胀的星形细胞足板挤压毛细血管使管腔狭窄或闭塞；神经元表现正常或有轻度可逆损伤。假手术组各个参数图、TTC染色、电镜以及光镜未见异常。大鼠脑局部星形细胞水肿模型实验组4只大鼠的rCBF和MTT参数图均见星形细胞水肿所造成的局部低灌注带和局部MTT延长区域，其中3只rCBV参数图显示异常低灌注区，2只TTP参数图显示TTP异常延长区域。rCBF、rCBV、MTT和TTP的比值范围分别为：0．25～0．44、0．70～1．01、1．20～2．00和1．02～1．45。电镜观察到星形细胞水肿，足板不同程度的肿胀，极度肿胀的星形细胞足板挤压毛细血管使管腔狭窄或闭塞；神经元基本正常或仅有核膜凹陷。对照组的CT灌注成像、TTC染色、电镜和光镜均未见异常。结论 rCBF下降到电衰竭阈值和膜衰竭阈值之间时，星形细胞可以作出比神经元更为迅速的反应，即星形细胞水肿。星形细胞足板肿胀使得毛细血管的管腔变窄，造成局部微循环障碍，加重脑局部的缺血缺氧。动态CT脑灌注成像可清楚地显示上述状态下异常血液动力学变化，rCBF与rCBV之间的变化关系可提示脑缺血区微循环障碍的程度。     

实验性大鼠脑血肿周围脑组织血流变化的CT灌注成像研究

目的 探讨建立大鼠脑血肿周围脑组织血流变化的CT灌注成像方法，并对其可行性进行研究。方法 雄性大鼠70只，采用随机数字抽样法将其分为注血组和对照组。分别将40μl新鲜自体血或生理盐水通过微量注射泵注入大鼠右侧尾状核制备脑出血模型。利用CT灌注成像对各组动物模型血肿周围脑组织血流变化进行观察，并与HE染色和红四氮唑(TTC)染色标本对照。通过计算机辅助CT脑灌注成像软件制作灌注CT参数图，并对血肿周围脑组织局部脑血流量(regional cerebral blood flow，rCBF)、局部脑血容量(regional cerebral blood volume，rCBV)和平均通过时间(mean transit time，MTT)进行相对值(病侧／健侧)测量。结果 注血组血肿周围脑组织存在不同程度低灌注梯度，血肿周围脑组织局部脑血流量(rCBF)呈波动性改变，在注血后1h rCBF降至最低，随后逐渐回升、下降，分别于注血后6h和24h2次回升至峰值。TTC染色血肿呈黑褐色，血肿周围未见白色梗死区。病理学检查显示在出血灶与正常脑组织间存在过渡带即血肿周围区，周围区内组织疏松，细胞不同程度水肿，星形细胞肿胀，神经细胞变性，出血灶周边可见毛细血管增生及炎细胞浸润。对照组CT灌注成像、TTC染色和病理学检查均未见明显异常。结论 大鼠脑血肿周围脑组织血流变化的CT灌注成像方法稳定可靠，能准确反映脑出血周围脑组织异常的血液动力学变化，是活体研究脑出血周围脑组织损伤较为理想的实验方法。     

实验性脑血肿周围组织脑血流变化的CT灌注成像与病理学研究

目的探讨血肿周围组织病理发展进程及其与血肿周围局部脑血流变化的关系。方法采用自体血注射法制备大鼠脑出血模型,对70只大鼠于术后1h、3h、6h、12h、24h、48h和72h7个时间点,利用GELightspeed螺旋CT扫描机灌注成像及计算机辅助系统制作大鼠脑CT灌注参数图,对血肿周围局部脑血流量(rCBF)、局部脑血容量(rCBV)和对比剂平均通过时间(MTT)脑血液动力学参数进行定量测量,并与大鼠脑TTC染色、HE-染色以及超微结构改变进行比较。结果大鼠脑血肿周围可见明显的低灌注梯度,血肿周围rCBF和rCBV显著降低,MTT延长。TTC染色血肿周围未见白色梗死区。HE-染色可见血肿周围区星形细胞肿胀,神经细胞变性、坏死,出血灶周边毛细血管增生伴炎细胞浸润。电镜观察显示,注血早期血肿周围组织星形细胞肿胀,神经细胞改变不明显,髓鞘板层松散;随着注血后时间延长,血肿周围组织损伤呈渐进性加重,星形细胞肿胀明显,神经细胞出现变性,髓鞘板层发生局部断裂、崩解。结论大鼠脑注血早期血肿周围局部脑血流的显著降低引发了血肿周围及远隔区脑组织的缺血性损伤,注血后急性期血肿周围组织细胞损伤呈进行性加重,血肿周围存在涉及多种细胞损伤机制的半暗带。     

大鼠脑局部星形细胞肿胀模型的CT灌注成像及病理学研究

目的 :研究脑局部星形细胞肿胀对局部脑血流的影响。方法 :选取体重在 2 5 0～ 3 0 0g雄性Wistar大鼠 2 1只 ,随机分为三组。将代谢型谷氨酸受体激动剂tACPD(实验组 )或生理盐水 (对照组 ) 2 μl注入右侧尾状核 ,6h及 2 4h后观察动物旋转运动情况 ,并行CT灌注成像检查后处死动物 ,测量左右尾状核干湿重并进行光镜和电镜观察。结果 :实验组动物注射后 6h出现向对侧旋转运动 ,右侧尾状核水含量与对侧及对照组比较差异有显著性意义 (P <0 .0 5 ) ,CT灌注成像均可见脑局部rCBF、rCBV明显下降 ,5例MTT及TTP延长。光镜HE染色及电镜组织学检查可见星形细胞肿胀、小血管受压等改变。注射后 2 4h实验组动物旋转活动、CT灌注成像及病理学检查均恢复正常。结论 :星形细胞肿胀可引起局部脑血流量下降 ,CT灌注成像可以清楚地反映局部脑血流动力学变化。当星形细胞肿胀恢复后 ,局部血流量可以恢复 ,CT灌注指标亦恢复正常。     

CT灌注成像对大鼠脑梗死半暗带的时间依赖性

目的：应用CT灌注成像对急性脑梗死缺血半暗带阈值进行判定,并着重探讨其时间依赖性。方法：取110只Wister大鼠,随机分为3组：对照组（10只）、缺血组（50只,分为5个亚组）、缺血再灌注组（50只,分为5个亚组）。用栓线法制作大鼠脑缺血动物模型,后2组于手术后5个时间点（2、4、6、8和10 h）分别行CT灌注成像检查,再灌注组经再灌注24 h后还需再次行CT灌注成像检查。检查结束后对图像进行判定,确定半暗带和最终梗死区的rCBF值,并取大鼠的脑组织进行病理观察。结果：缺血2 h和4 h的中心区及边缘区,缺血6、8和10 h的边缘区为半暗带,在缺血4 h之前,即使此区域的rCBF低至0.143,仍可逆;缺血6 h之后rCBF〉0.223以及10 h之后rCBF〉0.271的区域才有挽救的意义。病理检查显示在缺血6 h后,光镜和电镜发现有坏死神经细胞。结论：CT灌注成像能够判断半暗带及其阈值,预测其转归。在判断阈值应考虑到阈值与缺血时间的关系。     

13N-NH3心肌灌注显像评价兔心肌梗死模型缺血再灌注

目的　探讨兔心肌梗死模型缺血再灌注与梗死面积之间的关系。方法　完全闭塞 16只雄性新西兰大白兔冠状动脉左前降支 4 5min ,随机分为再灌注组 (n =8)和无再灌注组 (n =8) ,7～10d后行1 3N NH3PET CT心肌灌注显像 ,与三氯四氮唑 (TTC)染色梗死灶缺损百分比进行比较。HE染色评价梗死灶病理学改变。结果　TTC染色示无再灌注组、再灌注组实际梗死灶缺损百分比分别为 (2 5 7± 2 3) %、(2 1 5± 2 4 ) % (P =0 0 0 31)。1 3N NH3PET CT心肌灌注显像示 ,无再灌注组与再灌注组缺损百分比分别为 (2 4 6± 2 2 ) %和 (2 0 5± 2 5 ) % (P =0 0 0 37)。组内TTC染色与PET CT显像结果差异无显著性 (P >0 0 5 )。结论　1 3N NH3PET CT心肌灌注显像较TTC染色能更准确测定心肌梗死灶范围。     

CT引导下经皮穿刺活检术在骨骼病变诊断中的应用

目的探讨CT导引下肝细胞生长因子(HGF)基因治疗脑缺血的可行性。方法采用基因重组技术构建携带HGF基因的真核表达质粒,通过脂质体介导法,在CT灌注扫描图像定位下将其多点注射到大鼠急性脑梗死模型的缺血半暗带区域;转染7 d后断颈取脑,切片观察HGF基因于大鼠脑内的表达情况及其生物学效应。结果酶切鉴定及基因测序证实,HGF基因片段已克隆到PIRES2-EGFP的BamH I和Sal I位点之间。HGF基因转染大鼠缺血半暗带区7 d后免疫组化方法证实实验组大鼠转染局部已有HGF表达,血管数量明显多于对照组(P<0.01);CT灌注显示其梗死侧半球的脑血流量高于对照组(P<0.01);TTC染色显示实验组大鼠脑梗死体积小于对照组(P<0.01)。结论脂质体转染HGF基因能够在缺血半暗带区表达,其表达产物能够发挥生物学效应并促进局部侧支循环形成,从而改善脑缺血。     

急性脑静脉闭塞模型的CT灌注成像与病理学评价

目的用CT灌注成像（CTPI）和病理学方法对急性脑静脉闭塞动物模型进行评价. 材料与方法家猫22只,随机分为2组（手术组18只,假手术组4只）.手术组采用开颅上矢状窦穿刺注射液体栓塞剂--醋酸纤维素聚合物（CAP）制备急性脑静脉闭塞动物模型,术后1、3、6、12、24、48 h用CTPI对各组模型的脑血流动力学改变进行观察,其结果和病理学对照研究.假手术组只做钻孔颅骨开窗暴露上矢状窦,但不进一步操作. 结果手术组12只猫CTPI出现脑血流异常灌注区.术后1 h,病变表现为局部脑血容量（rCBV）轻度增加,局部脑血流量（rCBF）轻度降低,平均通过时间（MTT）稍延长;3～6 h后病变中心区主要表现为 rCBV和rCBF降低,而病变边缘区rCBV增加或正常或轻度降低,rCBF降低;12～24 h后病变中心区和边缘区rCBV和rCBF均明显降低.大体病理学检查上矢状窦、桥静脉及皮层静脉内见CAP凝固呈铸型改变,3 h后病变区见伊文思蓝不同程度蓝染.显微病理学检查10只猫出现脑实质损害,病变以血管源性水肿为主,12 h后出现出血性脑梗死.假手术组4只猫均未见上述各种异常表现. 结论功能CT灌注成像是评价急性脑静脉闭塞模型血流动力学改变的一种准确、敏感的方法,可早期评价脑实质损害的程度.     

Micro SPECT/CT活体评估大鼠超急性脑缺血的价值

目的 评价micro SPECT/CT对大鼠超急性期脑缺血的诊断价值.方法 选取24只健康雄性成年SD大鼠,以线栓法制作急性脑缺血模型.将大鼠模型按缺血后时间单纯随机抽样法分为6组,分别为缺血后1、2、3、4、5和6h组,6组动物均行99Tcm-ECD micro SPECT/CT脑灌注显像,各组显像后快速断头取脑,对脑组织行氯化三苯基四氮唑(TTC)染色及HE染色病理分析.计算micro SPECT/CT示梗死阳性(放射性分布稀疏或缺失,或患侧与健侧脑摄取比＜0.5)灶的梗死体积和TTC染色示梗死体积.同一时间点TTC染色及SPECT/CT结果比较采用配对t检验.结果 缺血后1、2、3、4、5和6h,micro SPECT/CT所示梗死体积分别为(98.50±27.77)、(110.40±26.80)、(157.00±36.82)、(165.50 ±26.54)、(175.75 ±31.16)和(177.25 ±34.33) mm3,SPECT所示缺血3h及以后梗死体积基本趋于恒定,3、4、5和6h各时间点梗死体积比较差异无统计学意义(均P＞0.05);TTC染色所示梗死体积分别为(73.98 ±27.76)、(90.75±29.00)、(135.00±40.83)、(136.25±22.51)、(158.50±32.72)和(168.00±32.75) mm3;各时间点组SPECT/CT与TTC染色所示梗死体积差异均无统计学意义(t=-1.681～-0.390,均P＞0.05).SPECT显示的放射性稀疏区域与TTC染色粉红色区域相对应.HE染色表现:缺血1、2h血管间隙增宽,神经细胞水肿;3、4、5和6h神经细胞核固缩,血管周围大量空泡状改变.结论 Micro SPECT/CT可在活体状态下快速、准确、无创地评价脑缺血大鼠模型的脑部血流动力学改变,这为临床SPECT/CT用于超急性期脑梗死的评估及指导治疗决策提供了实验依据.     

法舒地尔预处理对大鼠脑缺血再灌注损伤细胞色素C和caspase-3表达的影响

目的研究法舒地尔对大鼠局灶性脑缺血再灌注损伤细胞色素C（CytC）和caspase-3蛋白表达的影响,探讨其脑保护机制。方法线栓法制作大鼠中动脉缺血再灌注损伤模型。成年雄性SD大鼠120只随机分成3组：假手术组（Sham组）、脑缺血再灌注模型组（Mod组）、法舒地尔干预组（Fas组）,再分为再灌注3h、12h、24h和48h,以及TTC染色组5个亚组,每组8只大鼠。缺血再灌注后进行神经功能缺损评分（NDS）,免疫组织化学方法检测脑组织中CytC蛋白、cas-pase-3的表达,TTC染色测量鼠脑梗死体积并计算百分比。结果①Sham组大鼠无神经功能缺损,NDS评分为0,TTC染色亦未见脑组织梗死;Mod组和Fas组大鼠均有明显的神经功能缺损,TTC染色亦可见明显的脑组织梗死;但与Mod组相比,Fas组神经功能缺损少、NDS评分低（P〈0.01）,脑梗死体积减小（P〈0.05）。②与Sham组相比,脑缺血再灌注后,Mod组和Fas组大鼠脑组织CytC和caspase-3的表达显著升高（P〈0.01）,其中CytC表达高峰出现在12h,caspase-3表达高峰出现在24h;Fas组和Mod组间比较显示Fas组CytC和caspase-3的表达又显著低于Mod组（P〈0.01）。结论①法舒地尔能减轻大鼠脑局灶性缺血再灌注引起的神经功能缺损,减小脑梗死体积。②部分抑制脑缺血再灌注引起的CytC和caspase-3表达增加可能是法舒地尔的脑保护机制之一。     

CT灌注负荷试验评价慢性脑缺血的实验研究

目的:利用慢性缺血动物模型探讨CT灌注负荷试验的应用价值.方法:42号鼠随机分6组SD大鼠的双侧椎动脉和右侧颈总动脉,实验组结扎分别在术后1天、3天、7天、14天、21天(每组7只)行CT灌注检查.每只大鼠行两次灌注检查:静息状态和负荷状态(吸入8%的CO2 10min后).比较实验组和对照组两侧大脑半球(右/左)脑血流量和脑血容量的相对比值rCBF、rCBV的变化.结果:对照组大鼠两侧大脑半球灌注对称,静息状态下实验组rCBF、rCBV在血管结扎后均有明显下降,但很快即恢复正常水平(7天之后);而负荷状态下,rCBF、rCBV下降到7天时达到最低,之后逐渐恢复,在21天时与对照组比较仍有显著性差异(P＜0.01).负荷状态下rCBF、rCBV明显低于静息状态,统计学差异有显著性(P＜0.01).结论:相对于静息状态CT灌注,负荷试验显示了更严重的脑血液动力学损害.且两种状态下损害的时间过程不一致.提示负荷试验可更敏感地反应慢性脑缺血的状态.     

Measurement of cerebral hemodynamics with perfusion-weighted MR imaging: comparison with pre- and post-acetazolamide 133Xe-SPECT in occlusive carotid disease

BACKGROUND AND PURPOSE: We generated regional cerebral blood volume (rCBV) and regional cerebral blood flow (rCBF) studies from dynamic susceptibility contrast-enhanced MR images after an intravenous bolus injection of contrast agent (perfusion-weighted imaging [PWI]) by applying indicator dilution theory. We used a multishot echo-planar imaging (EPI) sequence to obtain adequate arterial input function (AIF). Our purpose was to compare the cerebral hemodynamics measured by PWI with the rCBF values and cerebral perfusion reserve obtained by xenon-133 single-photon emission CT (133Xe-SPECT). METHODS: Eight patients with chronic internal carotid artery occlusion or stenosis were examined. PWI data were acquired using a multishot EPI sequence, and the AIF was determined automatically. Our procedure was based on indicator dilution theory and deconvolution analysis. To eliminate the effect of superficial vessels, the automatic threshold selection method was used. RESULTS: AIF was adequate to generate rCBF and rCBV images. The rCBF and rCBV images by PWI were superior to 133Xe-SPECT scans in spatial resolution, and the rCBF values obtained by PWI correlated well with those obtained by 133Xe-SPECT. The regions with severely decreased perfusion reserve, which were determined by pre- and post-acetazolamide 133Xe-SPECT, showed significantly lower rCBF and higher rCBV by PWI than did regions with normal and moderately decreased perfusion reserve. CONCLUSION: The rCBF and rCBV images generated by our procedure using PWI data appear to provide important clinical information for evaluating the degree of cerebral perfusion reserve impairment in patients with chronic ischemia.     

Semiquantifying regional cerebral blood flow by 123I-amphetamine (IMP) SPECT in cerebrovascular disorders: correlations with CBF indices by 133Xe inhalation method

To examine the capacity of detecting regional cerebral blood flow (rCBF) disturbances in stroke, measurements with 133Xe inhalation and 123I-amphetamine (IMP) SPECT were performed within 1-2 days in 19 patients. IMP SPECT images in transverse sections consisting of outer and inner areas were correlated with 32 regions of 133Xe rCBF. 133Xe rCBF was assessed by ISI, CBF15, and F1. Inter hemispheric ratio correlation showed outer IMP uptake correlated better with 133Xe CBF indices than the inner one. With higher ratios of 133Xe rCBF. IMP uptake ratios were variable, suggesting less usefulness of this parameter in evaluation of mild ischemia. Values of IMP in outer regional hypo and hyperemic areas correlated better with those of 133Xe rCBF than the inner ones. In regional ratios of hypo and hyperemic areas from hemispheric mean, outer IMP uptake correlated with 133Xe CBF indices, reflecting regional disturbances of fast clearing tissue perfusion. Regression lines between ratios in 133Xe CBF and IMP uptake were located below one to one correlation, and dissociated more for hyperemic regions. IMP SPECT correlated better with 133Xe rCBF for tissues with reduced perfusion but underestimated hyperemic regions as measured with the 133Xe method. The data suggest outer cerebral IMP uptake evaluated by SPECT could reflect flow disturbances in the brain cortex.     

大鼠颅脑损伤动态CT灌注成像及相关病理生理学基础的初步研究

目的 探讨大鼠创伤性颅脑损伤后64排CT动态灌注成像的变化规律及其相关的病理生理学基础.方法 将80只成年雄性SD大鼠按照随机数字表法分为正常对照组、假致伤组以及致伤组,致伤组又分为2,6,12,24,48,72,120,168 h时相点组.致伤后各组分别进行CT灌注成像、脑含水量、血脑屏障通透性的测定,并观察病理改变,计算损伤区域CT灌注参数与病理生理学变化的相关性.结果 伤后2 h损伤区域血流灌注骤降达最小值,2～12 h内,相对脑血流量(rCBF)和相对脑血容量(rCBV)仍处于低灌注状态,但有所升高.相对平均通过时间(rMTT)延长,表面通透性(PS)增大.随着时间的延长,rCBF、rCBV逐渐升高,直至伤后24 h开始逆转,伤侧呈高灌注状态,PS值达最大.48 h为高灌注的顶峰期,后逐渐趋于正常.脑含水量于伤后2 h开始升高,48 h达到高峰期.伤后2 h血脑屏障通透性即开始增加,24 h达最大值.rCBF和rCBV与脑水肿的变化关系均呈正相关,PS与血脑屏障通透性的变化呈正相关.结论 CT灌注成像间接反映血脑屏障和水肿的演变过程,可以作为一种预测活体脑组织灌注和水肿程度的无创性影像学评价手段.

Abstract：

Objective To observe the variation of dynamic 64-slice CT perfusion imaging of rats with traumatic brain injury and discuss the relating pathophysiological basis.Methods A total of 80 adult male SD rats were randomly divided into three groups according to random number table,ie,normal control group,sham injury group and injury group.The injury group was divided into eight subgroups at time points of 2,6,12,24,48,72,120 and 168 hours.The detection of CT perfusion imaging,water content and blood-brain barrier permeability was done in the injured rats at all time points.The pathological changes were also observed to calculate their correlation with CT perfusion parameters of the injured region.Results The relative value of the blood perfusion was decreased significantly to the mimimum within 24 hours after injury.Within 2-12 hours,relative cerebral fluid(rCBF)and relative cerebral blood volume(rCBV)remained in a low perfusion state,with just a little increase.Relative mean transit time(rMTT)was prolonged and permeability surface(PS)increased.rCBF and rCBV were increased gradually with time,which was reversed till at 24 hours after injury and the injured side was in a high perfusion state,with the highest value of PS.The perfusion reached peak at 48 hours after injury and then became normal gradually.The water content was increased at 2 hours after injury and reached its peak at 48 hours.The permeability of blood-brain barrier(BBB)began to increase at 2 hours after injury and reached the peak at 24 hours.rCBF and rCBV were positively correlated with change of brain edema and PS was positively correlated with BBB permeability.Conclusion The dynamic 64-slice spiral CT perfusion imaging reflects the variation of BBB and edema and can be used as noninvasive imaging method for predicting the degree of brain perfusion and edema.     

Accuracy of dynamic perfusion CT with deconvolution in detecting acute hemispheric stroke

BACKGROUND AND PURPOSE: Dynamic perfusion CT (PCT) with deconvolution produces maps of time-to-peak (TTP), mean transit time (MTT), regional cerebral blood flow (rCBF), and regional cerebral blood volume (rCBV), with a computerized automated map of the infarct and penumbra. We determined the accuracy of these maps in patients with suspected acute hemispheric stroke. METHODS: Forty-six patients underwent nonenhanced CT and dynamic PCT, with follow-up CT or MR imaging. Two observers reviewed the nonenhanced studies for signs of stroke and read the PCT maps for TTP, MTT, rCBF, and rCBV abnormalities. Sensitivity, specificity, accuracy, and interobserver agreement were compared (Wilcoxon tests). Nonenhanced CT and PCT data were reviewed for stroke extent according to previously reported methods. Sensitivity, specificity, and accuracy of the computerized maps in detecting ischemia and its extent were determined. RESULTS: Compared with nonenhanced CT, PCT maps were significantly more accurate in detecting stroke (75.7-86.0% vs. 66.2%; P <.01), MTT maps were significantly more sensitive (77.6% vs. 69.2%; P <.01), and rCBF and rCBV maps were significantly more specific (90.9% and 92.7%, respectively, vs. 65.0%; P <.01). Regarding stroke extent, PCT maps were significantly more sensitive than nonenhanced CT (up to 94.4% vs. 42.9%; P <.01) and had higher interobserver agreement (up to 0.763). For the computerized map, sensitivity, specificity, and accuracy, respectively, were 68.2%, 92.3%, and 88.1% in detecting ischemia and 72.2%, 91.8%, and 87.9% in showing the extent. CONCLUSION: Dynamic PCT maps are more accurate than nonenhanced CT in detecting hemispheric strokes. Despite limited spatial coverage, PCT is highly reliable to assess the stroke extent.     

CT灌注成像对脑肿瘤瘤周水肿的评价

目的　应用CT灌注成像半定量估计脑肿瘤瘤周水肿的灌注状况。方法　应用SomatomPlus4螺旋CT机,对21例脑肿瘤瘤周水肿患者[脑膜瘤4例,胶质瘤(Ⅲ~Ⅳ级)7例、转移瘤10例]进行CT灌注成像,经灌注软件处理分别计算瘤周水肿区局部脑血流量(rCBF)、局部脑血容量(rCBV)、对比剂平均通过时间(MTT),并与对侧脑白质和不同肿瘤瘤周水肿间的灌注参数进行比较。结果　脑膜瘤和转移瘤瘤周水肿的rCBF和rCBV明显低于对侧脑白质(rCBF:t=2 .92和3 .82,P值均<0. 05, 0. 005;rCBV:t=2 .42和3. 53, P<0 .05, 0 .01),胶质瘤瘤周水肿的rCBF和rCBV与正常脑白质无明显差别(t=1 .00和1 .33, P值均>0 .05)。瘤周水肿区与对侧正常脑白质rCBF、rCBV比值,脑膜瘤和转移瘤之间差异无统计学意义(t=0 .23和0. 73, P值均>0 .05),胶质瘤明显大于脑膜瘤和转移瘤(t=3 .05和3. 37, P<0 .01, 0 .005)。结论　脑膜瘤和转移瘤瘤周水肿区的rCBF、rCBV显著降低,而胶质瘤瘤周水肿区接近或高于对侧脑白质,CT灌注能定量脑肿瘤瘤周水肿血流灌注状况,有助于肿瘤的鉴别和随访。     

CT灌注成像在脑梗死前期局部低灌注中的应用价值

目的: 探讨脑梗死前期局部低灌注的CT灌注成像的价值.材料和方法: 分析15例临床诊断为脑局部缺血CT平扫和CT增强扫描,常规MRI、MRA及CT灌注成像的表现.结果: 15例CT平扫和增强扫描均未发现新的脑梗死灶,CT灌注成像发现脑梗死前期脑局部低灌注I1期4例、I2期7例、II2期3例,MRI发现缺血灶14个,MRA发现一侧大脑中动脉狭窄2例,一侧大脑中动脉闭塞1例.结论: 脑梗死前期局部低灌注,常规CT,MRI无异常发现.CT灌注成像可超早期发现脑组织局部血流动力学异常,并可分期区分低灌注的脑局部微循环的病理生理学状态,对临床治疗有重要价值.