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1、CT灌流方法提供了对局部脑血流量，对脑实质的每个像素上的血流量进行量化测量的方法。反映组织的血管化程度及血流灌注情况，获得血液动力学方面的信息。,CT灌注成像 (Perfusion),扫描，获得一系列动态图像，分析对比加强曲线，得到造影剂通过每个像素所对应的体素密度的差异，获得反映血流灌注情况的参数。局部脑血容积（rCBV）、通过脑毛细血管的血液平均转换时间（MTT）、和局部脑血流量（rCBF）,CT灌注成像 (Perfusion),快速静脉注射含碘造影剂后(5ml/s以上)，在首次经过受检组织的过程中对某一选定的层面进行快速动态,脑梗塞肝、肾血流灌注及肿瘤的诊断肾移植的血流灌注的评价，了解移
2、植血管的情况 电子束CT的灌注可了解心脏灌注，有助于缺血性心肌病的早期诊断,CT Perfusion应用,由脑局部缺血而阻碍血液扩散是导致中风，占脑中风70%。血纤维蛋白可溶解闭塞的血管。发生中风后，有效治疗的时间为3小时左右。要尽快了解病情类型、发病时间和局部缺血的程度。在这段时间内常规CT检查较难发现，而灌注CT可应用于急性中风检查。,CT 灌注,前动脉供血区,中动脉供血区,后动脉供血区,外则 内侧 底面,脑动脉系统,脑动脉系统,在快速注射造影剂后，计算和脑的扩散有关的参数，从不同侧面提供中风的灌注分布情况：脑血液流量Cerebral Blood Flow, CBF脑血液容量Cerebra
3、l Blood Volume, CBV造影剂达到各点最大值的时间Time Peak，TP平均通过时间Mean transit time，MTT 通过 CBV 与 MTT 可获得 CBF,CT Perfusion,常规CT通过组织对X线不同衰减来显示图像CTA通过造影剂在血管内流动来显示血管结构灌注CT利用血液流动有关的参数CBF信号强示流速大造影剂到达高峰的时间分布图TPCBF与向脑组织提供氧的总量联系起来,CT Perfusion,紫色区域为血流量少,大脑急性中风区域,红色区域血流量大,CBF,71岁的妇女在症状开始90分钟后进行检查。CT平扫示无反常情况，但CBF示脑左侧(中脑和左半动脉供
4、血)大部分，(前脑动脉)提供地区严重局部缺血，示头颅内颈动脉的双枝闭塞。,左半脑症状出现60分钟后 (a)CT平扫无脑异常血液流动，(b)示左侧半脑广泛性和右前部的局部缺血。 原因：左颈内动脉闭塞。,CBF CBV Time-to-peak image,男44岁右脑中风约2小时，CBF在脑岛的脑皮层和豆状核后部，示严重扩散障碍(接近零)。与左边半球比较，中脑动脉血液供应相当少。CBV显示同样情况，但在右侧MCA其他地方血液容量接近正常。与左边区域比较，达到顶点时间图在延长(造影剂延迟到达)。MCA MI段栓塞和小脑膜血液供应良好，,CBF Time-to-peak image 3天后 CT,上
5、述病例进行动脉血纤维蛋白溶血处理后一天，用扩散CT成像显示了治疗效果，3天以后CT平扫，示梗塞形成，“核心“区域与CBF和CBV图像相似。,在梗塞核心区域范围确定方面，CT灌注能提供重要信息，可绘局部缺血轮廓，用高密度来显示。用于辨认梗塞灶核心和周围梗塞局部缺血(阴影)，为外科提供治疗方法。通常CBV的梗塞灶小于CBF和TP，MRI也如此，一般认为CBV提供的信息较正确。早期CBV减少与以后梗塞形成程度较接近。,CT 特点,与CBV(b)相比CBF (a)、TP(c)在MCA中局部缺血间不匹配。在脑岛脑皮层背部(箭)有一梗塞灶。 治疗法后24小时(d)在MCA同样位置示受限梗塞区。,71-ye
6、ar-old female patient with right-sided hemiplegia(偏瘫) and global aphasia(失语). Plain CT (90 minutes later) reveals no early signs of an ischemia(局部缺血).,The parameter images display the entire extent of the ischemia with a high-grade reduction of CBF and CBV, a lacking detection of the contrast bolus
7、in the time-to-peak image. The infarction(梗塞) includes the region of the anterior cerebral artery and large portions of the region supplied by the middle cerebral artery, both features indicative of an occlusion of the intracranial carotid bifurcation.,Case 1,Patient (male 44) with a right-sided isc
8、hemia in the region of the middle cerebral artery (MCA) which began 160 minutes ago. Typical findings of a high-grade disturbance in perfusion in the insular cortex and the posterior portion of the lentiform nucleus with a reduction in CBF and CBV as a result of an embolic occlusion in the distal M1
9、 segment.The other regions supplied by the MCA demonstrated good leptomeningeal collateral blood supply which only showed moderately reduced CBF and CBV values, as well as a prolongation of the time-to-peak.,Case 2,In the calculation of relative perfusion indices from CBF values in ischemic areas an
10、d in mirrorred ROIs within the unaffected hemisphere proved to be a valuable method for the prognostic evaluation of a region with reduced perfusion.The core of the infarct and the ischemic marginal zones demonstrate clearly different CBF perfusion indices (green-marked ROI = 0.17 versus red-marked
11、ROI = 0.69 ).,The findings of perfusion CT could be verified by DSA with regard to the type of occlusion and the condition of the collateral blood supply . The follow-up CT after a successful intra-arterial fibrinolysis shows the infarct in dimensions comparable to the infarct core seen with perfusi
12、on CT.,70 minutes after the occurrence of the infarction, the CBF image revealed a highgrade ischemia in the frontal region of the supply area of the MCA and in the lentiform nucleus (Fig. 3a) with a perfusion index in the greenmarked ROI of 0.07 (Fig. 3b). As a result of the good collateral flow, t
13、he disturbance in perfusion in the remaining region of the MCA, with a perfusion index of 0.82, is not seen to be very extensive (red-marked ROI in Fig. 3b).,36-year-old male patient with an embolic occlusion in the M1 segment of the left MCA and a simultaneous occlusion of the left internal carotid
14、 artery as a result of dissection.,Case 3,Because of the partially high-grade ischemia on the one hand and the excellent collateral blood supply of the marginal region on the other, fibrinolysis was not performed in spite of the short time interval. As expected, the follow-up CT revealed the develop
15、ment of an infarction in the area which had primarily demonstrated a high-grade ischemia.,灌注CT与颅脑CT扫描和颅脑CT血管造影术结合为脑梗塞早期检查提供了一种有用工具。常规CT可检查梗塞区域的形成灌注CT可决定局部缺血的区域，提供了局部缺血组织的位置和潜在病变区域CT血管造影术为诊断提供了相应病灶区域的形态。 为临床工作人员决定进一步治疗的方案提供了重要信息。,CT Perfusion前景,目前认为中风处理的最佳时间在60分钟。灌注CT在不到15分钟中完成中风评价过程。,In the course o
16、f an investigation performed on 33 patients, an attempt was made to carry out a quantitative evaluation of the severity of the ischemia with the aid of an ROI-evaluation of the CBF images.,the calculation of relative perfusion indices from CBF values in ischemic areas and in mirrorred ROIs within the unaffected hemisphere proved to be a valuable method for the prognostic evaluation of a region with reduced perfusion.,
