多模式CT在评估急性缺血性卒中脑侧支循环中的应用

多模式计算机断层扫描（computed tomography,CT）包括CT平扫（non-contrast CT,NCCT）、 CT灌注成像（CT perfusion,CTP）、CT血管成像（CT angiography,CTA）,可以对急性缺血性卒中后侧支 循环进行全面评估,评估脑灌注状态,了解脑侧支循环建立或开放情况,判断临床预后,在急性缺血 性卒中的诊疗过程中发挥重要的作用。本文就多模式CT在缺血性卒中中的应用进行综述,以期使患 者获益更多。     

脑灌注成像预测溶栓后出血转化风险的研究进展

出血转化是缺血性卒中的常见并发症之一,其中溶栓治疗导致继发性出血转化风险明显 增加是困扰临床医生的重要问题。目前认为血脑屏障的破坏在出血转化的发生中起到关键的作用。 近来研究显示,急性期的灌注影像检查对于出血转化高风险人群检出可能具有更高的敏感性和其 他优势。本文针对灌注成像在预测急性缺血性卒中患者溶栓后出血转化的研究进展方面做一综述。     

多模式CT在缺血性卒中诊疗中的应用

缺血性卒中已成为危害人类健康的主要疾病,急需一种快速有效的影像学检查协助诊断、 指导治疗、预测病因、判断预后。多模式计算机断层扫描（computed tomography,CT）检查可一次性获 取脑组织结构、血管及血流灌注等方面信息,为缺血性卒中患者个体化治疗及二级预防提供客观的 影像学依据。文章就多模式CT在缺血性卒中诊疗中的应用进行综述。     

糖调节异常对缺血性卒中患者脑组织毛细血管渗透性和出血转化的影响

目的 观察急性缺血性卒中患者脑缺血组织毛细血管渗透性变化特点,分析糖调节异常对缺血组织 毛细血管渗透性和发生出血转化的影响。 方法 连续入组的急性缺血性卒中患者,收集患者人口学资料、既往病史、临床信息、实验室指标、 影像资料等。采用口服葡萄糖耐量试验（oral glucose tolerance test,OGTT）进行糖调节异常类型的 诊断。对患者进行计算机体层扫描（computer tomography,CT）灌注成像和渗透性表面（permeabili ty surface,PS）彩色图像叠加后处理,评价缺血脑组织的毛细血管渗透性。对患者进行头颅磁共振梯度 回波成像或CT平扫,评价缺血组织发生出血转化情况。采用Logistic回归模型分析糖调节异常对出血 转化（hemorrhagic transformation,HT）的影响。 结果 研究期间共入组420例急性缺血性卒中患者。与糖调节正常患者相比,合并糖尿病的缺血性卒中 患者脑组织低灌注区的毛细血管渗透性显著升高（P =0.006）。发生出血转化的患者缺血组织毛细血管 渗透性较未发生出血转化者有增加趋势（[ 5.79±3.01）ml/（100 m·l min）vs（4.82±3.29）ml/（100 m·l min）, P =0.530]。Logistic回归分析显示,校正混杂因素后,发病（14±3）d空腹血糖升高,是缺血性卒中后 发生出血转化的独立危险因素[比值比（odd ratios,OR）1.448,95%可信区间（confidence interval,CI） 1.017～2.061,P =0.04）]。 结论 合并糖尿病的缺血性卒中患者缺血组织毛细血管渗透性显著升高;糖调节异常可能通过增 加缺血组织毛细血管渗透性,继而增加卒中患者HT的风险。     

多模式CT指导下的扩大时间窗溶栓治疗病例分析

目的 探讨在多模式计算机断层扫描（computed tomography,CT）指导下,急性缺血性卒中4.5～9 h重组 组织型纤溶酶原激活剂（recombinant tissue plasminogen activator,rtPA）静脉溶栓的有效性及安全性。 方法 选取在2008至2009年南京大学医学院附属鼓楼医院神经内科临床诊断为急性缺血性卒中且 发病时间在4.5～9 h的6例患者为研究对象,经多模式CT筛选后,进行rtPA（0.9 mg/kg）静脉溶栓治 疗。溶栓前以及溶栓后2 h、24 h和7 d进行美国国立卫生研究院神经功能缺损评分（National Institutes of Heath Stroke Scale,NIHSS）评估神经功能缺损和恢复情况,溶栓后7 d和90 d时行巴氏指数量表 （Barthel Index,BI））评估日常生活能力和改良Rankin量表（modified Rankin Scale,mRS）评估神经功 能,在溶栓后24 h复查多模式CT评估血管再通情况。血管狭窄程度采用缺血性卒中血管栓塞程度量表 （Thrombolysis in Cerebral Ischemia Scale,TICI）分级方法。 结果 在入选的6例患者中,1例患者发生脑出血和病情恶化。6例患者TICI分级评分在溶栓24 h后 较溶栓前显著升高（2.0+0.71 vs 1.0+0.71,P =0.03）。除去1例出血患者,溶栓治疗前后的NIHSS 评分分别为12.2±3.27（溶栓前）和9.4±3.78（溶栓后7 d）,差异具有显著性（P =0.04）。在日常生 活能力方面,与溶栓后7 d相比,BI评分在溶栓后90 d后稍有提高,但差异无显著性（62.5±27.23 vs 47.5±27.84,P =0.13）。患者90 d mRS评分较7 d mRS评分有所好转,但差异无显著性（4±0.82 vs 3±0.82,P =0.09）。 结论 多模式CT指导下扩大静脉溶栓治疗时间窗对促进卒中患者血管再通、神经功能恢复和日常生 活能力提高有促进作用。     

卒中后出血转化的影像学评估

出血转化是缺血性卒中患者静脉溶栓及血管内治疗最严重的并发症之一,对于缺血性卒 中患者,在考虑卒中急性期血流再灌注、避免血管再闭塞的同时,关注出血转化高风险人群的筛查是 提高卒中治疗质量的关键之一。颅脑CT、CTA、MRI、DWI、SWI及灌注成像等多种神经影像学诊断技术可 快速获取有关卒中性质、核心梗死灶体积、病灶及周围血流灌注状态、血管病变程度及病变血管管 壁通透性等相关信息,以预测患者的出血转化风险,指导临床医师治疗措施的选择,从而改善患者 预后。     

急性缺血性卒中静脉溶栓前后多模式影像评估分析

目的应用多模式影像学检查对急性缺血性脑卒中静脉溶栓进行评估。方法回顾性分析行急性缺血性卒中静脉溶栓的患者69例,通过对比缺血性脑卒中患者静脉溶栓前后多模式影像检查方法的选择及临床疗效进行研究。结果静脉溶栓前仅检查CT的占68.1%;静脉溶栓前开启多模式影像的占31.9%。静脉溶栓后立刻或同时开启多模式影像的占30.4%。结论结合医院放射科设备配置及卒中中心发展状况,溶栓二线合理选择适合自身特点的多模式影像并判断何时开启多模式影像;结合灌注成像的分析确定梗死核心和缺血半暗带,为超时间窗的rt-PA静脉溶栓和血管内治疗进行指导评估,使更多的缺血性卒中患者从中受益。     

急性缺血性卒中出血转化的研究进展

出血转化是急性缺血性卒中再灌注治疗后的主要并发症之一，与缺血性卒中预后不良密 切相关。急性缺血性卒中的主要治疗方案，包括阿替普酶静脉溶栓、血管内治疗及抗血小板聚集药 物治疗等均可能导致出血转化。目前临床上尚无对缺血性卒中出血转化有效的预测方法，本文对缺 血性卒中出血转化的病因以及影像学和生物学标志物进展进行综述，旨在为出血转化的预防和治疗 提供参考。     

建立急性缺血性卒中的临床/多模式CT预后评分系统

目的 建立一个简便、有效的临床/多模式CT评分系统,用以指导急性缺血性卒中患者的临床治疗和评估90 d后临床功能恢复情况。方法 选择49例急性缺血性卒中（发病时间＜9 h）的患者行“多模式CT”扫描,包括平扫CT（non-contrast enhanced computed tomography,NCCT）、CT灌注成像（computed tomography perfusion,CTP）和CT血管成像（computed tomography angiography,CTA）;评价患者基线NCCT、动脉期CTP原始图（arterial phase CTP source images,ACTP-SI）、静脉期CTP原始图（venous phase CTP source images,VCTP-SI）、CTA卒中溶栓分级（thrombolysis in cerebral ischemia scale,TICI）、Alberta卒中项目早期CT评分（Alberta Stroke Program Early CT Score Study,ASPECTS）及基线美国国立卫生研究院卒中量表（National Institute of Health Stroke Scale,NIHSS）评分,并应用受试者工作特征曲线（receiver-operating characteristics,ROC）分析,判断90 d临床功能恢复良好［采用改良的Rankin量表（modified Rankin Scale,mRS）<2作为评判标准］的临床和CT参数阈值;按照获得的阈值进行评分,将多模式CT各参数的阈值评分整合在一起获得多模式CT评分系统,将基线NIHSS阈值评分加入多模式CT评分系统中获得临床/多模式CT评分。最后应用ROC曲线分析比较各评分模式预测临床功能恢复的效能。结果 判断90 d临床功能恢复良好的阈值：临床/多模式CT评分>1,多模式CT评分>1,基线NCCT ASPECTS>9,动脉期CTP原始图ASPECTS>6.5,静脉期CTP原始图ASPECTS>8.5,CTA TICI>1及基线NIHSS≥7;临床/多模式CT评分ROC曲线下面积最大（0.87,95%可信区间0.75～0.95),其预测急性缺血性卒中患者90 d临床功能恢复的效能最高,接下来依次是多模式CT评分、ACTP-SI、VCTP-SI、NIHSS、NCCT及CTA,除临床/多模式CT评分与ACTP-SI（P=0.226）及NIHSS阈值评分（P=0.174）的差异显著性外,其余各参数阈值评分与临床/多模式CT评分的差异均有显著性（P＜0.05）。结论 应用临床/多模式CT评分系统比多模式CT及NIHSS各参数单独预测90 d急性缺血性卒中患者的临床功能恢复的效能均高,临床/多模式CT评分系统是预测患者预后的有效评分方法。     

磁共振技术在急性缺血性卒中出血转化预测中的应用

出血转化（hemorrhagic transformation,HT）是缺血性卒中最严重的并发症之一。近年来,随 着技术的发展,磁共振能较准确地反映HT的生理机制,例如通过弥散加权技术反映细胞的代谢障 碍,灌注加权技术反映组织的灌注缺损,血脑屏障通透性技术反映血脑屏障破坏程度,进而在此 基础上评估HT的风险。本文将对磁共振技术在预测缺血性卒中发生HT的应用及进展做一综述。     

CT脑灌注与血管造影在急性缺血性脑卒中的临床应用与分析

目的探讨CT脑灌注(CTPI)与血管造影在急性缺血性脑卒中中的临床应用价值。方法选择29例急性缺血性脑卒中患者为研究对象,采用东芝Aquilion 64排CT行头颈部CTA及CTPI检查,观察两者对急性缺血性脑卒中诊断情况,分析CTPI与CTA对急性缺血性脑卒中诊断的一致性。结果①29例患者CT灌注图上发现与临床症状相对应的灌注异常区共25例,阳性率为86.2%(25/29),高于普通CT扫描的27.6%(8/29),差异具有统计学意义(P0.05)。②灌注异常区的CBF、CBV、MTT三组参数值与镜像健侧相比差异有显著统计学意义(P0.05);③CTA血管检查结果发现单纯颈内动脉狭窄5处;单纯颅内动脉狭窄10处;颈内动脉及颅内动脉均狭窄4例。④病例组CTPI联合CTA检查结果比较,病例组存在责任血管的患者CTPI检查阳性率为65.51%(19/29)高于无责任血管者的20.69%(6/29),差异具有统计学意义(P0.05)。结论 CTPI与CTA可以清晰的显示缺血性脑卒中脑内病灶及责任动脉,能够提高更多有价值的信息。     

缺血性脑卒中早期CT灌注成像的临床应用价值

目的 探讨缺血性脑卒中早期CT灌注成像（CTPI）的临床应用价值。方法 对45例发病24h内的缺血性脑卒中患者行头颅CT平扫与CTPI检查，计算缺血半暗带区及梗死区相对脑血流量（rCBF）、相对脑血容量（rCBV）、相对平均通过时间（rMTT）、相对峰值时间（rTTP）、相对峰值增强（rPE）的灌注参数及各个参数图异常灌注区面积。结果 CT平扫显示脑缺血性改变29例，其中为责任病灶21例，未见异常16例，未见责任病灶24例；对缺血性脑卒中早期诊断的敏感性为46．67％（21／45），特异性为72．41％（21／29）。CTPI显示灌注异常44例，均为责任病灶；灌注正常1例，后经头颅MRI证实为急性脑干梗死；对缺血性脑卒中早期诊断的敏感性为97．78％（44／45），特异性为100％（44／44）。CTPI较CT平扫对急性脑缺血性病灶更敏感（P〈0．01）。缺血半暗带区及梗死区各个灌注参数相对值之间呈正相关（均P〈0．01）。CTPI各个参数图异常灌注区面积之间呈正相关（均P〈0．01）。结论 CTPI能够早期诊断缺血性脑卒中；定量分析可区分中心梗死区、缺血半暗带区，有助于早期选择治疗方案。     

脑卒中患者急性期脑电生理变化与CT成像的临床研究

目的 探讨急性缺血性脑卒中患者脑电生理变化和CT成像的临床意义. 方法 对56例发病后即刻入院的缺血性脑卒中患者检测的CT、脑电图(EEG)、脑电地形图(BEAM)、体感诱发电位(SEP)、经颅磁刺激运动诱发电位(MEP)和神经功能缺损评分(MESSS)及日常生活能力评分(BI)情况进行对比研究及相关分析. 结果 EEG局限性异常与CT显示病变位置基本一致,但病灶范围存在一定差异.自身患/健侧SEP和MEP比较差异有统计学意义(P<0.05).入院不同时间MESSS与入院第28天BI值分析显示两者呈正相关(r=0.58,P<0.05).结论 CT成像与脑电生理检查在缺血性脑卒中急性期具有较高的早期诊断价值.     

A Pictorial Essay of Brain Perfusion‐CT: Not Every Abnormality Is a Stroke!

Perfusion‐CT (PCT) of the brain is a rapidly evolving imaging technique used to assess blood supply to the brain parenchyma. PCT is readily available at most imaging centers, resulting in steadily increasing use of this imaging technique. Though PCT was initially introduced and still most widely used to evaluate patients with acute ischemic stroke, a wide variety of other pathologic processes demonstrate abnormal perfusion maps. Therefore, it is important for the radiologist to recognize altered perfusion patterns observed in diseases other than typical ischemic stroke. The goal of this article is to show the perfusion maps and review the perfusion patterns observed in some subtypes of atypical stroke and in neurological entities other than stroke, so that they are recognized and not confused with the PCT patterns observed in patients with typical ischemic stroke.     

VCTDSA联合CT灌注成像对急性缺血性脑卒中影像诊断价值

目的探讨容积CT数字减影血管造影VCTDSA联合CT灌注成像在急性缺血性脑卒中的诊断价值。方法对30例临床诊断为急性缺血性脑卒中的患者于发病后24h内行VCTDSA联合CT灌注成像,观察CT平扫表现及灌注图像、VCTDSA重建图像结果。测定相应区域脑血流量(CBF),脑血容量(CBV),平均通过时间(MTT)和达峰时间(TTP)。结果 25例急性缺血性脑卒中患者头部CT平扫未发现与临床症状相对应的脑缺血区,CT灌注图上可发现与临床症状相对应的脑缺血区。CT灌注成像表现为CBF下降、CBV下降、MTT延长、TTP延长或无TTP出现。VCTDSA可见23例患者相应责任血管的不同程度的狭窄,其余7例患者未检出相应责任血管狭窄。结论 CT灌注成像在急性缺血性脑卒中的早期诊断中有很重要的价值。VCTDSA能发现缺血病变的原因,为临床进一步治疗提供确切依据。     

Choice of neuroimaging in perioperative acute stroke management

At the time of this publication, the fast examination time, wide availability, lack of contraindications, and high accuracy for detecting hemorrhage make NCCT the diagnostic study of choice for initial evaluation of patients who have preoperative stroke. NCCT also has a role in excluding patients who will not benefit from IV thrombolysis, including those who have ICH and patients who have ASPECTS less than 7 or ischemic signs exceeding one third of the MCA territory. Because optimal selection of inpatients who have acute stroke mandates not just brain tissue data but also information about the aortic arch, cervical and intracranial vasculature, and cerebral hemodynamics, additional imaging with multimodal CT technology can, in one scanning session, depicts early ischemic changes, demonstrates hypoperfusion/ischemic penumbra, and locates the vascular lesion. When combined with the clinical scenario, the information provided by CT often is sufficient to help clinicians decide on the appropriate treatment, especially determining eligibility for thrombolysis. The rapidly evolving field of neuroradiology will provide a newer armamentarium in the near future. Although MRI can provide more precise information, it is more time consuming and currently should be considered the method of choice for follow-up imaging, rather than initial imaging, in patients who have perioperative stroke.     

Imaging viable brain tissue with CT scan during acute stroke

Viability of the cerebral parenchyma is dependent on cerebral blood flow (CBF). The assessment of cerebral perfusion in patients with acute stroke, in a clinically relevant time frame, could be of utmost importance for patient selection before thrombolytic therapy. In individual patients, quantitative mapping of CBF to indicate the severity and potential reversibility of neuronal damage can be used to predict which brain tissue will be salvaged with reperfusion or die without it (penumbra), as well as which brain tissue is already infarcted. Recent investigations of perfusion CT have shown major advances in the assessment of acute stroke patients. Perfusion CT offers a number of practical advantages over other cerebral perfusion imaging methods as it can be performed immediately after unenhanced CT, and used, in general, to exclude cerebral haemorrhage. It is fast (typical procedure time <5 min) and does not require specialized computer hardware. The accuracy of cerebral perfusion maps has been demonstrated for normal and decreased CBF value by comparison with xenon CT used as a gold standard. Perfusion CT infarct and penumbra maps provide a potential recuperation ratio (PRR) (or Lausanne Stroke Index), defined as PRR = penumbra/ (penumbra + infarct). This index is correlated with the improvement of the National Institutes of Health Stroke Scale (NIHSS) in case of arterial recanalization. Also, the size of the ischaemic area (infarct + penumbra) is correlated with the NIHSS score on hospital admission. Further studies may demonstrate the use of perfusion CT for the assessment of penumbra dynamics in function-specific brain areas. Perfusion CT is now ready to be used in clinical trials as a decision-making tool to tailor more precisely the thrombolytic therapy to the individual patient.     

Prognostic accuracy of cerebral blood flow measurement by perfusion computed tomography, at the time of emergency room admission, in acute stroke patients

The purpose of this study was to determine the prognostic accuracy of perfusion computed tomography (CT), performed at the time of emergency room admission, in acute stroke patients. Accuracy was determined by comparison of perfusion CT with delayed magnetic resonance (MR) and by monitoring the evolution of each patient's clinical condition. Twenty-two acute stroke patients underwent perfusion CT covering four contiguous 10mm slices on admission, as well as delayed MR, performed after a median interval of 3 days after emergency room admission. Eight were treated with thrombolytic agents. Infarct size on the admission perfusion CT was compared with that on the delayed diffusion-weighted (DWI)-MR, chosen as the gold standard. Delayed magnetic resonance angiography and perfusion-weighted MR were used to detect recanalization. A potential recuperation ratio, defined as PRR = penumbra size/(penumbra size + infarct size) on the admission perfusion CT, was compared with the evolution in each patient's clinical condition, defined by the National Institutes of Health Stroke Scale (NIHSS). In the 8 cases with arterial recanalization, the size of the cerebral infarct on the delayed DWI-MR was larger than or equal to that of the infarct on the admission perfusion CT, but smaller than or equal to that of the ischemic lesion on the admission perfusion CT; and the observed improvement in the NIHSS correlated with the PRR (correlation coefficient = 0.833). In the 14 cases with persistent arterial occlusion, infarct size on the delayed DWI-MR correlated with ischemic lesion size on the admission perfusion CT (r = 0.958). In all 22 patients, the admission NIHSS correlated with the size of the ischemic area on the admission perfusion CT (r = 0.627). Based on these findings, we conclude that perfusion CT allows the accurate prediction of the final infarct size and the evaluation of clinical prognosis for acute stroke patients at the time of emergency evaluation. It may also provide information about the extent of the penumbra. Perfusion CT could therefore be a valuable tool in the early management of acute stroke patients.