早期低脑血流量和高乳酸血症预测蛛网膜下腔出血后迟发性脑缺血的临床研究

目的 探讨早期低脑血流量和高乳酸血症对蛛网膜下腔出血(SAH)后迟发性脑缺血(DCI)的预测作用。方法 选择2010年1月-2014年12月来本院接受治疗的SAH患者90例; 根据患者有无DCI发生分为DCI发生组(n=35)和DCI未发生组(n=55); 根据病历信息及临床检查详细记录SAH患者的年龄、性别、体质量指数(BMI)、烟酒嗜好,高血压病、糖尿病史和现状、治疗方式,责任动脉瘤位置、血肿形成、脑积水、有无高乳酸血症、Hunt-Hess分级、Fisher分级等; 应用单因素、多因素非条件Cox回归分析预测SAH后DCI发生的危险因素。结果 90例SAH患者中35例(38.89%)发生DCI,55例(61.11%)未发生DCI。2组患者在性别、Fisher分级、Hunt-Hess分级、血肿形成、脑积水、有高乳酸血症、脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)、达峰时间(TTP)方面差异显著(P<0.05)。其中,DCI发生组在高乳酸血症患者比例方面显著高于DCI未发生组(P<0.05),在CBF方面显著低于DCI未发生组(P<0.05)。CBF、CBV、MTT、TTP的ROC曲线下面积分别为0.88、0.70、0.89、0.73,预测DCI最佳诊断界值分别为15.95 mL·100 g^-1·min^-1、1.77 mL·100 g^-1、9.62 s、11.48 s。 单因素、多因素Cox回归分析显示,有高乳酸血症、Hunt-Hess分级≥Ⅲ级、Fisher分级≥Ⅲ级、CBF<15.95 ml/100 g/min会增加SAH后DCI发生的风险(P<0.05)。结论 早期低脑血流量和高乳酸血症可预测SAH后DCI发生。     

急性缺血性脑血管病76例多模式CT影像学分析

目的探讨76例急性缺血性脑血管病(AICVD)的多模式CT影像学特点。方法采用320排多层螺旋CT对76例AICVD(发病时间24h)患者急诊进行CT平扫(NCCT)+CT灌注成像(CTP)+CT血管成像(CTA)一站式扫描检查,分析灌注区脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)、达峰时间(TTP)等灌注参数变化及CT血管成像(CTA),并于入院后3d内行头颅MRI,评估其脑灌注特点及血管影像。结果在获取的76例CTP数据中,通过感兴趣区识别划分筛查,有59例患者有明确的异常CTP,有17例患者未发现明确感兴趣区。59例异常CTP中包括急性脑梗死47例,短暂性脑缺血发作(TIA)12例。急性脑梗死患者异常CTP特点:发病在4.5h以内的4例患者CTP表现为患侧CBF均较健侧下降,CBV正常或者轻度增高,MTT、TTP延长;发病时间在4.5~6h内的4例:其中2例CTP表现为CBF降低,CBV正常,MTT、TTP延长,2例表现为CBF降低,CBV轻度降低,MTT、TTP延长;发病时间在6~24h内的39例:其中30例梗死区与CTP异常脑灌注区部位一致,均表现CBF明显降低,CBV明显降低,MTT、TTP延长;12例TIA患者CTP均发现与临床症状相对应的灌注异常:MTT、TTP延长,CBF正常或减低,CBV升高。CTA发现责任动脉重度狭窄5例,血管闭塞10例,7例可见血流缓慢,排空延迟及侧支血管形成。结论多模式CT能够对AICVD提供血流灌注参数的变化及血管情况、供血区的血流动力学变化,对临床诊治具有一定参考价值,主要用于评估大脑半球卒中,多模式CT有临床价值。     

早期高压氧治疗对急性脑梗死患者脑血流灌注状态的影响及预后的临床研究

目的通过观察急性脑梗死患者早期高压氧治疗前、后脑血流量(CBF)、脑血容量(CBV)、脑血流平均通过时间(MTT)、峰值时间(TTP)和梗死体积的变化,系统评价早期高压氧治疗急性脑梗死的临床疗效和安全性。方法使用CT灌注成像测定患者的脑血流灌注参数,MRI测定梗死体积。结果 2组患者治疗前CBF、CBV、MTT、TTP及脑梗死体积的比较差异无显著性(P>0.05)。2组患者治疗15d后2组患者CBF、CBV提高,MTT、TTP下降,梗死体积明显缩小,与治疗前比较差异明显(P<0.01),高压氧治疗组疗效更好,2组比较差异明显(P<0.01)。结论早期高压氧治疗对急性脑梗死的疗效显著。     

CT灌注成像评价血肿穿刺置管引流术对血肿周围脑组织血流动力学的影响

目的探讨血肿穿刺置管引流术(简称引流术)对自发性幕上出血患者血肿周围组织血流动力学的影响。方法 30例自发性幕上出血患者于引流术后行CT灌注成像,以血肿侧和对侧镜像区血肿中央区、血肿周围水肿区、血肿周围水肿区外侧(距离水肿边缘1 cm)和远隔皮质区作为兴趣区,测量各区域脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)和达峰时间(TTP)。结果 (1)脑出血后血肿周围组织存在不同程度低灌注。与对侧镜像区相比较,血肿侧血肿中央区CBF值(P=0.000)和CBV值(P=0.000)降低、MTT值延长(P=0.000),但未见峰值;血肿周围水肿区CBF值(P=0.000)和CBV值(P=0.000)降低、MTT值延长(P=0.000);血肿周围水肿区外侧CBF值(P=0.000)和CBV值(P=0.000)降低;而血肿侧与对侧镜像区远隔皮质区CBF、CBV、MTT和TTP值差异均无统计学意义(P0.05)。(2)脑出血后自血肿中央区至远隔皮质区灌注参数呈阶梯样改变。血肿侧自血肿中央区至远隔皮质区CBF值和CBV值逐渐增大(均P 0.05)、MTT值逐渐减少(均P 0.05),而TTP值差异无统计学意义(P 0.05);对侧镜像区血肿中央区、血肿周围水肿区、血肿周围水肿区外侧与远隔皮质区CBF、CBV、MTT和TTP值差异均无统计学意义(P 0.05)。(3)引流术后血肿周围水肿区CBF值(P=0.000)和CBV值(P=0.000)高于术前。结论血肿穿刺置管引流术可以明显提高血肿周围组织血流灌注。     

640层螺旋CT脑灌注成像与CT血管成像在超早期脑梗死中的应用

目的探讨东芝Aquilion ONE 640层CT脑灌注成像(CTP)与CT血管成像(CTA)在超早期脑梗死患者中的应用价值。方法我院2014-06—2015-12收治的28例超早期脑梗死患者,均在发病后6h内实施CT平扫、CTP与CTA检查,分析平扫及灌注CT表现,计算CTP的达峰时间(TTP)、脑血流量(CBF)、脑血容量(CBV)各参数值,并与对侧及半暗带周边相应区灌注参数相对比;重建颈段和脑内动脉CTA图像,采用图像后处理技术显示病变血管情况,对动脉狭窄程度进行分级评价。所有患者3~7d内行多层螺旋CT复查,评估CTP与CTA在超早期脑梗死诊断中的临床价值。结果 28例患者经头颅CT平扫发现,11例有可疑脑缺血区,其余17例未见明显异常。行CT脑血管灌注成像发现,患者感兴趣区内rCBF、rCBV、rTTP(病变侧与对照侧灌注参数的相对比值)明显改变,脑梗死区较边缘区TTP更高,CBF、CBV更低,差异均有统计学意义(P0.01);半暗带区CBF、TTP与对侧比较差异有统计学意义(P0.01),而CBV对比差异无统计学意义(P0.05)。CTA检查发现,10例患者大脑中动脉闭塞,7例大脑中动脉狭窄,11例一侧颈内动脉狭窄或闭塞。结论 CTP早期发现脑梗死患者脑组织中的缺血半暗带,CTA检查可准确判断狭窄或闭塞血管,在脑梗死患者的早期诊断和指导溶栓治疗中有重要临床价值。     

CTP参数对短暂性脑缺血发作近期进展为急性脑梗死的预测价值探讨

目的 探讨计算机断层扫描灌注成像(CTP)参数对短暂性脑缺血发作(TIA)近期进展为急性脑梗死(ACI)的预测价值。方法 回顾性分析2017年4月至2020年12月该院收治的176例TIA患者的临床资料,随访3个月,将进展为ACI的25例患者纳入ACI组,未进展为ACI的151例患者纳入非ACI组。对比2组患者基线资料、脑部CTP参数,并分析CTP参数对评估TIA后3个月发生ACI的预测价值。结果 176例TIA患者中,有25例进展为ACI,ACI发生率为14.20%。ACI组与非ACI组在性别、身体质量指数、TIA类型比较,差异均无统计学意义(P>0.05)。ACI组年龄、合并高血压、合并糖尿病、合并高脂血症占比均高于非ACI组,差异有统计学意义(P<0.05);脑部CTP参数中,ACI组患者脑血流量(CBF)、脑血容量(CBV)水平低于非ACI组,差异有统计学意义(P<0.05);ACI组患者平均通过时间(MTT)、最大峰值时间(TTP)水平高于非ACI组,差异有统计学意义(P<0.05)。CBF、CBV、MTT、TTP评估TIA进展为ACI的Cut-off值分别为33.26 mL/(100 g·min)、2.04 mL/100 g、11.33 s、16.08 s;各项指标联合评估TIA进展为ACI的灵敏度为100%;特异度与各项指标单独评估比较,差异无统计学意义(P>0.05);AUC均高于各项指标单独评估(P<0.05)。结论 TIA近期进展为ACI过程中CTP参数会发生变化,即CBF、CBV水平下降,MTT、TTP水平升高。CBF、CBV、MTT、TTP及各项指标联合对评估TIA进展为ACI均有一定的预测价值,且各项指标联合对ACI的预测价值更佳。     

急性脑梗死的320排动态容积CT脑灌注成像研究

目的研究320排动态容积CT全脑灌注成像(CTP)在脑梗死患者中的价值。方法对2014-01—2016-01驻马店市中心医院收治的33例脑梗死患者采取CT全脑灌注成像检查,测量梗死核心区、缺血半暗带(IP)与健侧镜像区的脑血流量(CBF)、脑血容量(CBV)、达峰时间(TTP)及平均通过时间(MTT)值,计算梗死核心区及IP的相对脑血流量(rCBF)、相对脑血容量(rCBV)、相对达峰时间(rTTP)、相对平均通过时间(rMTT),并进行对比分析。结果 33例患者中,头颅平扫发现9例早期脑梗死征象,其余24例未发现异常。33例患者行CTP成像均发现异常灌注区,其中25例存在IP;与健侧镜像区对比,CBV无显著差异(P0.05),而TTP、MTT值明显延长,CBF显著降低,差异有统计学意义(P0.05);与梗死核心区对比,CBF、CBV升高,TTP缩短,MTT延长,差异均有统计学意义(P0.05)。IP区与梗死核心区rCBF、rCBV、rTTP、rMTT对比,差异有统计学意义(P0.05)。10例超急性期(发病6h以内)、15例急性期(发病6~72h)中11例、8例亚急性期(发病72h~14d)中4例存在IP。缺血半暗带分期:Ⅰ2期6例,Ⅱ1期12例,Ⅱ2期7例。结论 320排动态容积CT全脑灌注成像可通过注射一次对比剂获得常规CT、CTP、CTA数据,对脑梗死患者的病变部位、范围及有无IP等提供明确的影像学依据,且可对IP进行分期,为临床实现对患者的个体化治疗提供了可能,且显著降低了患者所受的辐射剂量,安全性高。     

头颅CT灌注成像对烟雾病行间接血流重建术的疗效评价

目的研究探讨头颅CT灌注成像（CTP）技术对缺血型或出血型烟雾病（MMD）患者行间接血流重建术（indirect revascularisation）的总体疗效评价。方法 47例缺血性或出血卒中起病并由数字减影血管造影（DSA）证实的MMD患者,采用颅骨多点钻孔术（MBHT）、脑-颞肌贴敷术（EMS）、脑-颞肌-动脉贴敷术（EDAMS）、脑-硬脑膜-动脉贴敷术行间接血流重建术。并于术前、术后1周、术后3个月分别行头颅CT灌注成像检查,分别对脑血流量（CBF）、脑血容量（CBV）、达峰时间（TTP）进行定量和定性检查分析,并对手术前后及随访的CBF、CBV、TTP进行对比分析。结果 MMD患者术前与术后早期（1周）CTP各参数比较,额颞叶CBF、CBV变化无统计学差异,TTP显著降低,差异有统计学意义（P〈0.05）;术后3个月CTP与术后1周比较,额、颞叶rTTP、rCBV降低;差异有统计学意义（P〈0.05）。慢性缺血型MMD患者术后症状改善明显。结论 CT灌注成像作为一项快速简便的脑血流状况的检测技术,能反映脑微循环信息的功能成像,尤其是其TTP等时间参数对区分缺血程度具有很高的敏感性,能显示早期细微的缺血变化,MMD间接血流重建术后侧支血管的形成和脑血流的改善远早于造影上新生血管的形成,可以解释间接血流重建术后早期在造影可见的吻合血管出现之前就出现临床症状的明显改善。该检查有助于判断MMD脑缺血的部位和程度、选择手术侧别和手术方式,更为了解间接血流重建术后缺血程度是否改善提供较客观的评判依据。     

多层螺旋CT灌注成像对星形细胞肿瘤分级的准确性评价

目的 评价多层螺旋CT灌注成像(CTP)参数对星形细胞肿瘤分级的敏感性和特异性.方法 对第三军医大学第三附属医院野战外科研究所收治的53例脑肿瘤患者进行CTP检查,经手术和病理学证实为星形细胞肿瘤的30例患者纳入研究对象.CTP采用GE LightSpeed 64层螺旋CT机行灌注扫描,在AW4.2P后处理工作站对原始数据进行后处理,测定肿瘤最大灌注区和对侧正常组织的脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)及毛细血管表面通透性(PS).手术获取脑肿瘤标本进行组织病理学检查.结果 星形细胞肿瘤高级别组CBF、CBV和PS值均明显高于低级别组,差异有统计学意义(P<0.05),MTT值比较差异无统计学意义(P>0.05).受试者工作特征曲线(ROC曲线)分析表明,CBF、CBV和PS值对鉴别高、低级别星形细胞肿瘤的ROC曲线下面积分别为0.914、0.876和0.914,而MTT无鉴别作用,其ROC曲线下面积为0.455.采用CBF=62.635 mL/(100 g·min),CBV=4.310 mL/100 g和PS=5.925 mL/(100 g·min)作为分界点鉴别高、低级别星形细胞肿瘤的敏感性均为84.2%,特异性分别是81.8%、81.8%和91.9%.结论 多层螺旋CTP参数CBF、CBV及PS值对鉴别高、低级别星形细胞肿瘤具有较高敏感性和特异性.     

慢性脑供血不足患者脑血流变化的多层螺旋CT灌注成像研究

目的 探讨慢性脑供血不足(CCCI)患者脑血流变化的多层螺旋CT灌注成像(CTPI).方法 用64层螺旋CT对25例CCCI患者和20名正常对照者进行CTPI检查,感兴趣区(ROI)选择双侧豆状核、丘脑、额、颞、顶、枕叶、放射冠区,测量其脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)和达峰时间(TTP),并对两组结果进行比较.结果 与正常对照组比较,CCCI组各个脑区的CBF、CBV均显著降低(P＜0.05 ～0.01),MTT、TTP值的差异无统计学意义.CCCI组额叶、深部白质的CBF、CBV比其他脑区明显降低(均P＜0.05);而左右侧各脑区CTPI参数的差异均无统计学意义.结论 CCCI患者各脑区的CBF、CBV明显降低,以额叶和深部白质明显.     

CT perfusion and delayed cerebral ischemia in aneurysmal subarachnoid hemorrhage: a systematic review and meta-analysis

Delayed cerebral ischemia (DCI) is at presentation a diagnosis per exclusionem, and can only be confirmed with follow-up imaging. For treatment of DCI a diagnostic tool is needed. We performed a systematic review to evaluate the value of CT perfusion (CTP) in the prediction and diagnosis of DCI. We searched PubMed, Embase, and Cochrane databases to identify studies on the relationship between CTP and DCI. Eleven studies totaling 570 patients were included. On admission, cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and time-to-peak (TTP) did not differ between patients who did and did not develop DCI. In the DCI time-window (4 to 14 days after subarachnoid hemorrhage (SAH)), DCI was associated with a decreased CBF (pooled mean difference −11.9 mL/100 g per minute (95% confidence interval (CI): −15.2 to −8.6)) and an increased MTT (pooled mean difference 1.5 seconds (0.9–2.2)). Cerebral blood volume did not differ and TTP was rarely reported. Perfusion thresholds reported in studies were comparable, although the corresponding test characteristics were moderate and differed between studies. We conclude that CTP can be used in the diagnosis but not in the prediction of DCI. A need exists to standardize the method for measuring perfusion with CTP after SAH, and optimize and validate perfusion thresholds.     

Changes in Cerebral Perfusion with Induced Hypertension in Aneurysmal Subarachnoid Hemorrhage: A Pilot and Feasibility Study

Background

The effects of induced hypertension (IH) on cerebral perfusion after subarachnoid hemorrhage (SAH) are unclear. The objectives of this investigation are to: (1) determine whether there are differences in cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) measured with computed tomography perfusion (CTP) before and after IH; (2) evaluate differences in the presence of infarction and clinical outcome between patients with and without IH.

Methods

We performed a retrospective cohort analysis of 25 aneurysmal SAH patients. IH was initiated as per the standard institutional protocol when patients showed clinical symptoms of delayed cerebral ischemia (DCI). Differences in CBF, CBV, and MTT between early (<72 h after aneurysm rupture) and late (7–10 days after aneurysm rupture) CTP were quantified in patients with (n = 13) and without IH (n = 12). Outcome measures included cerebral infarction and clinical outcome at 3 months.

Results

Early MTT was significantly greater in the IH group compared to the no-IH group. There was no difference in early or late CBV or CBF between the two groups. In patients that received IH, there was a significant decrease in MTT between the early (7.0 ± 1.2 s) and late scans (5.8 ± 1.6 s; p = 0.005). There was no difference in the incidence of infarction (5/13 vs. 2/11) or poor outcome (3/11 vs. 6/13) between the IH and no-IH groups, respectively (p > 0.05).

Conclusions

Elevated MTT is a significant factor for the development of DCI in patients eventually requiring IH therapy and is improved by IH treatment. Therapies to prevent DCI and improve clinical outcome may need to be initiated earlier, when cerebral perfusion abnormalities are first identified.

     

Whole brain CT perfusion combined with CT angiography in patients with subarachnoid hemorrhage and cerebral vasospasm

Objective

To assess cerebral vasospasm (CVS) and monitor cerebral microcirculatory changes in patients with acute subarachnoid hemorrhage (SAH) via CT angiography (CTA) combined with whole-brain CT perfusion (CTP) techniques.

Methods

Sixty patients with SAH (SAH group) and 10 patients without SAH (control group) were selected for a prospective study. CTP combined with CTA and digital subtraction angiography (DSA) studies were performed on patients with initial onset of SAH less than three days. CTA and DSA as well as the CTP parameters such as cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), and time-to-peak (TTP) were acquired and analyzed. The relationship of CTA and CTP measurements was assessed in these acute SAH patients.

Results

CTP techniques were used to achieve the perfusion maps of the whole brain in patients with acute SAH. Compared to the control group, mean CBF value was significantly lower while both MTT and TTP values were significantly higher in SAH group (all p < 0.05). Further analysis revealed that mean CBF in patients with CVS, sCVS, Fisher III–IV and Hunt–Hess III–V significantly decreased when compared to patients with nCVS, asCVS, Fisher I–II and Hunt–Hess I–II (p < 0.05). Furthermore both MTT and TTP values were also significantly reduced in patient with CVS, sCVS, Fisher III–IV and Hunt–Hess III–V (p < 0.05).

Conclusion

The study demonstrated that changes of microcirculation in patients with SAH could be assessed by whole-brain CTP. CTP combined with CTA could detect both macroscopic evident vasospasm on CTA and alterations of microcirculation on CTP. Mean CBF was significantly lower in patients with SAH.     

Whole-Brain Permeability Analysis on Admission Improves Prediction of Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage

PurposeTo evaluate the changes of blood-brain barrier permeability (BBBP) after aneurysmal subarachnoid hemorrhage (aSAH) and find out whether BBBP within 24 h after onset can further improve prediction of delayed cerebral ischemia (DCI).MethodsCT perfusion (CTP) was performed within 24 h after onset and in the DCI time window (DCITW). Whole brain average values of flow extraction product (mK^trans), qualitative and quantitative CTP parameters, and clinical data were compared between DCI and non-DCI groups. The changes of mK^trans were analysed using a Paired t test. Multivariate logistic regression analysis and ROC analyses were performed to identify predictors of DCI and evaluate the predictive performance.ResultsOne hundred and forty of 179 consecutive patients were included, 45 of whom (32%) developed DCI. mK^trans was higher in the DCI group both on admission and in the DCITW (P<0.001). mK^trans decreased significantly in the non-DCI group (P=0.003), but not in DCI group (P=0.285). Multivariate logistic regression analysis showed that mK^trans (OR=1.07, 95%CI: 1.03-1.11, P<0.001), World Federation of Neurosurgery Scale (OR=6.73, 95%CI: 1.09-41.41, P=0.040), Hunt-Hess grade (OR=0.16, 95%CI: 0.02-1.19, P=0.073), modified Fisher Score (OR=3.74, 95%CI: 1.30-10.75, P=0.014), and qualitative CTP (OR=4.31, 95%CI: 1.49-12.47, P=0.007) were independent predictors of DCI. The model with K^trans produced a larger AUC of 0.88 (95%CI: 0.81-0.95), with corresponding sensitivity and specificity of 84% and 86%, respectively.ConclusionBBBP measurement within 24 h after onset can improve the prediction of DCI. Early moderate BBB disruption may be reversible, whereas severe BBBP disruption indicates the risk of DCI.     

早期脑血流量检测在预测蛛网膜下腔出血迟发性脑缺血患者预后的作用研究

目的探讨早期脑血流量检测对蛛网膜下腔出血(SAH)迟发性脑缺血(DCI)患者预后的预测作用。方法选择2008年1月～2012年11月来我院接受治疗的SAH后DCI患者150例。根据5年后患者临床结局分为存活组(n=96)和死亡组(n=54)。比较两组患者在临床特征方面的差异。绘制ROC曲线,计算曲线下面积评估各参数的预测效力。应用单因素、多因素非条件Cox回归分析预测SAH后DCI患者预后的危险因素。采用Kaplan-Meier法绘制累积生存曲线,采用Log-Rank法比较生存率差异。结果 150例患者术后5年96例(64%)存活,54例(36%)死亡。单因素、多因素Cox回归分析结果显示,脑血流量(CBF)15.82ml/100g/min、PAASH分级≥4级、Fisher分级≥III级不利于患者预后(P0.05)。随访5年后,CBF15.82 ml/100 g/min的患者累积生存率为18%(9/50),显著低于CBF≥15.82 ml/100 g/min患者的累积生存率45%(45/100)(P0.05)。结论入院时CBF可作为预测SAH后DCI患者预后的重要指标。     

症状性大脑中动脉狭窄率与组织灌注的相关性

目的 应用单一症状性M1段狭窄模型定量分析症状性大脑中动脉狭窄率与组织灌注的相关性.方法 从连续203例症状性颅内动脉狭窄选择性支架成形术患者中严格筛选所有单一M1段狭窄患者.所有患者均进行头颅CT、CT灌注(CTP)和DSA检查.根据CTP检查结果,测量两侧从前往后包括额叶、前分水岭、岛盖、颞叶、后分水岭和枕叶的各脑区CTP各参数.CTP参数包括平均通过时间(MTT)、脑血流量(CBF)和脑血容量(CBV).以健侧作为正常对照,计算患侧各脑区CTP参数相对值和判定患侧各脑区CTP各参数变化.根据DSA造影结果,肓法手工测量M1段狭窄率和判断侧支代偿动脉来源及侧支血流分级.对M1段狭窄率与患侧各脑区CTP各参数绝对值、相对值进行相关性分析.结果 20例患者入组,患侧M1段狭窄率平均为70.5%±10.6%(53%～91%).以对侧为对照,患侧额叶MTT正常,CBF正常,CBV升高;前分水岭MTT延长,CBF正常,CBV升高;岛盖MTT延长,CBF正常,CBV升高;颞叶MTT延长,CBF正常,CBV正常;后分水岭MTT延长,CBF下降,CBV正常;枕叶MTT正常,CBF正常,CBV正常.狭窄M1段供血相关脑区,从前往后各脑区血流灌注逐渐减低;而后分水岭是惟一处于血流失代偿期的脑区.所有患者DSA显示侧支代偿均主要来自大脑前动脉软脑膜支.M1段狭窄率与后分水岭区相对CBV正相关(r=0.66,P=0.002);与其余各脑区各CTP灌注参数均没有相关性.结论 症状性大脑中动脉狭窄患侧各脑区组织灌注水平受侧支代偿动脉的影响有明显空间分布效应;M1段狭窄率与血流失代偿期脑区相对CBV呈正相关,与血流代偿期脑区组织灌注没有相关性.

Abstract：

Objective To quantitatively analyze the correlation between stenosis ratio and cerebral perfusion in patients with solely symptomatic M1 stenosis of middle cerebral artery.Methods All the patients with solely symptomatic M1 stenosis of middle cerebral artery were selected to this study from consecutive 203 patients with elective stenting of symptomatic intracranial artery stenosis.Brain CT, CT perfusion (CTP) and DSA examinations were performed in all cases.The CTP parameters of mean transit time (MTT), cerebral blood flow (CBF) and cerebral blood volume (CBV) were measured in regions of interest (ROIs) including bilateral frontal lobe, anterior watershed, opercula of the insula (including parsopercluaris and part of insula), temporal lobe, posterior watershed and occipital lobe.Compared with the unaffected side as control, the change of CTP and their relative CTP parameters in these ROIs at affected side were analyzed.Based on DSA data, the ratio of M1 stenosis was measured manually and blindly, the source of collateral branch of compensative artery was estimated and the blood flow was graded.Correlation between the ratio of M1 stenosis and the CTP parameters including the absolute and the relative values was investigated.Results Twenty patients were selected into this study; their average M1 stenosis ration of the affected side was 70.5% ± 10.6% (53% to 91%).Compared with the unaffected side, MTT and CBF were no significant change but CBV increased in the affected frontal lobe; MTT prolonged, CBF was normal and CBV increased in the affected anterior watershed and opercula of the insula; MTT prolonged, CBF and CBV had no significant difference in the affected temporal lobe; MTT prolonged, CBF decreased and CBV had no significant difference in the affected posterior watershed; MTT, CBF and CBV were normal in occipital lobe.Tissue perfusion gradually decreased from the front to the backward in all the M1 stenosis affected cerebral regions and the posterior watershed area was the only region at hemodynamic failure stage.Leptomeningeal vessels of the anterior cerebral artery were the major sources of compensative arteries shown in the DSA in all cases.The ratio of M1 stenosis was positively correlated (r =0.66, P =0.002) with the rCBV in posterior watershed and there is no significant correlation between the ratio and any other CTP parameters in any regions.Conclusions Associated with distribution of collateral compensative artery,tissue perfusion showed obvious spatial distribution at different level in different cerebral region.M1 stenosis ratio is positively correlated with rCBV in hemodynamic failure regions, and there is no correlation with tissue perfusion in hemodynamic compromise regions.     

Perfusion computed tomography: prediction of final infarct extent and stroke outcome

The Alberta Stroke Program Early Computed Tomography Score (ASPECTS) has not been previously applied to perfusion CT (CTP). Five raters assigned ASPECTS to baseline noncontrast CT (NCCT), CT angiography source images (CTA-SI), CTP source images (CTP-SI), and CTP maps of cerebral blood volume (CBV), cerebral blood flow (CBF), and mean transit time (MTT) from 37 consecutive patients with less than 6-hour anterior circulation ischemic stroke. Major reperfusion was identified on follow-up imaging. Mean baseline ASPECTS was compared with follow-up imaging ASPECTS. Rates of favorable outcome were compared for dichotomized baseline ASPECTS. In patients with major reperfusion, mean CBV and CTP-SI ASPECTS closely predicted final infarct ASPECTS. In patients without major reperfusion, mean CBF and MTT ASPECTS best predicted final infarct ASPECTS. There were significant increases in rates of favorable outcome for CTP-SI and CBV ASPECTS of greater than 6, versus less than or equal to 6, but not for other baseline CT modalities. ASPECTS applied to CTP is more accurate at identifying the extent of reversible and irreversible ischemia and at predicting final clinical outcome than NCCTor CTA-SI.     

Acute Effect of Intravenous Sildenafil on Cerebral Blood Flow in Patients with Vasospasm After Subarachnoid Hemorrhage

Background

The phosphodiesterase-5 inhibitor sildenafil has been shown to attenuate delayed cerebral ischemia (DCI) and improve neurologic function in experimental subarachnoid hemorrhage (SAH). We recently demonstrated that it could improve cerebral vasospasm (CVS) in humans after SAH. However, successful therapies for DCI must also restore cerebral blood flow (CBF) and/or autoregulatory capacity. In this study, we tested the effects of sildenafil on CBF in SAH patients at-risk for DCI.

Methods

Six subjects with angiographically confirmed CVS received 30-mg of intravenous sildenafil (mean 9 ± 2 days after aneurysmal SAH). Each underwent ¹⁵O-PET imaging to measure global and regional CBF at baseline and post-sildenafil.

Results

Mean arterial pressure declined by 10 mm Hg on average post-sildenafil (8 %, p = 0.01), while ICP was unchanged. There was no change in global CBF (mean 34.5 ± 7 ml/100g/min at baseline vs. 33.9 ± 8.0 ml/100g/min post-sildenafil, p = 0.84). The proportion of brain regions with low CBF (<25 ml/100g/min) was also unchanged after sildenafil infusion.

Conclusions

Infusion of sildenafil does not lead to a change in global or regional perfusion despite a significant reduction in cerebral perfusion pressure. While this could reflect the ineffectiveness of sildenafil-induced proximal vasodilatation to alter brain perfusion, it also suggests that cerebral autoregulatory function was preserved in this group. Future studies should assess whether sildenafil can restore or enhance autoregulation after SAH.

     

一站式全脑动态容积 CTP-CTA 成像对颅脑损伤后脑血管痉挛的诊断价值

目的 探讨一站式全脑动态容积CT灌注成像(CTP)联合CT血管成像(CTA)成像在颅脑损伤后脑血管痉挛中的应用及临床意义.方法 50例可疑有症状性脑血管痉挛表现的患者接受一站式全脑动态容积成像,CTP检查结果与对侧镜像区进行比较.结果 50例颅脑损伤患者中48例患者CTP存在原脑损伤范围外的低灌注区,同临床症状相符,准确性达96%,同对侧镜像区进行比较,各参数脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT)及达峰时间(TTP)差异皆有统计学意义;50例颅脑损伤患者其中42例患者3D-CTA存在颅内大血管痉挛.结论 一站式全脑动态容积CTP-CTA成像技术应用于颅脑损伤后脑血管痉挛,通过CTP显示脑实质低灌注区以判断脑实质微循环血管痉挛的存在,CTA判断脑实质外大血管痉挛的存在,即CTP联合CTA对颅脑损伤后脑血管痉挛的早期诊断、治疗方案的选择、疗效的评估均有重要临床价值.