灌注及弥散磁共振成像在急性缺血性脑卒中的应用

目的　评估磁共振 (MRI)弥散加权成像 (DWI)及灌注加权成像 (PWI)在急性缺血性卒中指导溶栓治疗的应用价值。方法　对 44例急性 (≤ 6h)缺血性卒中患者行DWI、PWI扫描 ,DWI及PWI的不匹配区为缺血半暗带 ,根据半暗带是否存在确定患者是否适合溶栓治疗。结果　脑梗死患者 33例 ,其中 2 3例 (52 3 % )有明显半暗带存在 (PWI >DWI) ;1 0例 (2 2 7% )无明显半暗带 (PWI=DWI)。临床表现为短暂性缺血发作 (TIA)者 1 1例 (2 5 0 % )。结论　PWI及DWI对照研究有助于发现超早期脑梗死半暗带 ,指导溶栓治疗 ;临床表现结合DWI有助于除外TIA     

CT灌注成像联合血管成像在老年急性缺血性脑血管病中的应用价值

目的观察临床应用CT灌注成像联合血管成像对老年急性缺血性脑血管病的应用价值。方法选取2012-04—2015-12在我院进行诊治的77例急性缺血性脑血管病患者给予CT灌注成像联合血管成像检查,并根据CT、MRI检查分为短暂性脑缺血发作及脑梗死2组,分析2组患者的发病情况及血管成像检查结果、CT灌注成像参数。结果 CI组患者的CBV、CBF较健侧明显下降(P0.05),TTP和MTT较健侧明显延长(P0.05);TIA组与健侧相比仅有TTP及MTT明显延长(P0.05),CBV和CBF无明显变化(P0.05);总血管狭窄发生率为66.23%;发生血管狭窄患者CTPI阳性率明显高于无出现血管狭窄患者,差异有统计学意义(P0.05)。结论临床应用CT灌注成像联合血管成像能够为临床医师及时诊断、治疗老年急性缺血性脑血管病提供客观依据。     

磁共振成像技术在缺血性脑血管病临床实践中的意义

目的:评估磁共振成像(MRI)弥散加权成像(DWI)、灌注加权成像(PWI)及磁共振血管造影术(MRA)在缺血性脑血管病临床实践中的意义。方法:对78例发病在10d内的急性缺血性脑血管病患者进行DWI、PWI及MRA检查,对不同发病时期患者的临床与影像改变进行对照研究。结果:急性/亚急性脑梗死灶,相对脑血容量(rCBV)下降,平均通过时间(MTT)延长。62例脑梗死中,41.9％有缺血半暗带,部分患者复查MRI,可发现梗死的进展;58.1％无半暗带存在。急性/亚急性梗死灶DWI表现为高信号,7例患者不同血管分布区有多发新鲜脑梗死灶,陈旧梗死灶表现为低信号。71.8％的患者MBA所显示的血管狭窄或闭塞与DWI病变一致。结论:MBA可提供大的动脉的供血状态;PWI在缺血区提供最早、最直接的血流下降情况;DWI反映脑细胞功能状态。PWI与DWI的研究可确定缺血半暗带,动态观察缺血性损害的进展,判断缺血的预后。     

灌注磁共振成像在缺血性脑血管病外科治疗中的作用

目的探讨灌注磁共振成像(PWI)在缺血性脑血管病外科治疗中的作用。方法回顾性分析24例缺血性脑血管病患者的临床及影像学资料。并对外科治疗患者术前、术后均行PWI检查,以比较患者的脑血流灌注情况。结果本组患者中,单侧颈内动脉严重狭窄或闭塞9例,单侧大脑中动脉严重狭窄或闭塞8例,颅内、外动脉系统多发性狭窄或闭塞5例,烟雾病2例。术前PWI显示局部脑血流量(rCBF)正常、平均通过时间(MTY)升高15例,rCBF降低、MTT升高8例,rCBF和MTT均正常1例。23例接受外科治疗,其中13例行支架血管成形术,4例行颈动脉内膜切除术,6例颞浅动脉一大脑中动脉(STA—MCA)动脉吻合术;术后PWI改善19例(82．6％),其中支架血管成形术12例(92．3％),颈动脉内膜切除术4例(100％),STA—MCA吻合术3例(50％)。结论PWI可以评价缺血性脑血管病患者的脑血流灌注异常及外科治疗后有效地改善脑血流灌注的情况。     

弥散成像和血流灌注成像磁共振诊断急性缺血性脑血管病的意义

目的评价弥散成像（DWI）、血流灌注成像（PWI）磁共振对急性缺血性脑血管病的诊断价值。方法用DWI、PWI诊断急性脑缺血,并与常规MRI结果比较。结果经MRI检查证实的急性缺血性脑血管病患者共22例。其中发病后90分钟至6小时检查者11例,其CT及常规MRI未见异常,3例短暂性脑缺血发作（TIA）患者的DWI、PWI正常;其余8例脑梗死患者经DWI、PWI检查,均发现相对应的病灶,且6例灌注减低体积（PWIv）＞弥散异常体积（DWIv）,2例PWIv＝DWIv。起病在6－12小时5例,4例行PWI检查,3例PWIv＞DWIv,1例PWIv＝DWIv。起病在12－48小时6例,2例行PWI检查,PWIv＝DWIv。8例陈旧病灶在DWI上表现为低信号,所有新病灶在DWI上均为高信号。结论DWI、PWI可超早期诊断脑梗死,并可帮助了解缺血半暗带。T2加权像和DWI结合可以鉴别新旧梗死灶。     

双源FLASH螺旋CT脑灌注联合CT血管造影在超早期脑梗死患者的应用价值

目的探讨双源CT灌注成像(PWI)及动脉成像(CTA)对超早期脑梗死的诊断价值。方法选择30例超早期脑梗死患者为研究对象,均接受双源FLASH螺旋CT-PWI及CTA检查,测量并比较脑梗死区、边缘区及健侧对照区脑血流量(CBF)、脑血容量(CBV)、平均通过时间(MTT),并观察头颈部动脉病变情况。结果与健侧对照区比较,脑梗死区、边缘区MTT更高,CBF更低,差异具有统计学意义(P0.05)。与边缘区比较,脑梗死区CBV、CBF更低,MTT更高,差异具有统计学意义(P0.05)。30例患者中,15例为多发狭窄,10例为单发狭窄,共显示动脉狭窄100处。狭窄部位以大脑中动脉狭窄最多见,占33%。狭窄程度以重度狭窄多见,占48%。灌注异常区域与狭窄脑动脉供血区符合率为80%。结论在超早期脑梗死的诊断中,双源CT灌注成像(PWI)及动脉成像(CTA)能够提供有价值的信息,值得临床应用。     

动脉自旋标记技术(ASL)在一侧大脑中动脉狭窄或闭塞中脑组织灌注信息的研究

目的探讨动脉自旋标记技术(ASL)对大脑中动脉狭窄或闭塞灌注信息的诊断价值,为指导临床治疗提供依据。方法回顾性分析36例TIA患者及5例健康志愿者,对比弥散成像(DWI)与灌注成像即动态磁敏感对比增强(DSC)和动脉自旋标记技术(ASL)显示病灶大小的情况,得到平均通过时间(MTT),达峰时间(TTP),脑血容量(CBV),脑血流量(CBF)图,分析DSC和ASL结果的差异。结果DSC检查患侧与健侧灌注程度改变,T=2.91,α水平设在0.05,P<0.01,有统计学意义。ASL检查患侧与健侧灌注程度的改变,T=2.37,α水平设在0.05,P<0.05,具有统计学意义。对比DSC及ASL方法显示患侧灌注程度,卡方值为-0.984,P>0.05为无统计学差别。结论用ASL完全无创性的方法,对灌注程度进行定量的分析,且实行方便、操作简单,这种灌注成像对缺血性脑血管病的诊断价值得以肯定。     

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。     

DWI和PWI在脑梗死中的联合应用价值

目的应用弥散加权成像(DWI)与灌注成像(PWI)在脑梗死中的联合应用,探讨不同时期脑梗死的DWI信号表现特点与血管微循环变化,了解病变与血管微循环之间的关系及判断预后,辅助制定治疗方案。方法选取自2010-04-2011-11收入我院神经内科病房的不同时期脑梗死患者40例,男22例,女18例,除常规序列MRI检查,所有患者均行DWI和PWI检查,用西门子Trio3.0TMR机采集灌注原始数据,在工作站中进行数据后处理,获得MR伪彩灌注图像(包括rCBF图、rCBV图、MTT图、TTP图)进行分析;ADC值的定量测量。结果超急性期脑梗死4例,急性期脑梗死13例,亚急性期脑梗死17例,正常4例,慢性期脑梗死6例,超急性期到慢性期脑梗死DWI信号遵循从高到低,ADC信号遵循从低到高变化特点。DWIPWI 20例DWI=PWI。结论 DWI在超急性脑梗死的诊断中具有重要价值,根据DWI与ADC的信号变化,准确判断脑梗死的各个时期;PWI可以反映梗死区的微血管分布和血流再灌注情况,对脑缺血做出提前诊断,对临床治疗进行指导;DWI与PWI相结合,可以确定缺血半暗带,指导临床治疗     

不同磁共振成像模式判断胶质母细胞瘤预后研究

目的探讨动态磁敏感增强灌注成像(DSC-MRI)、三维动脉自旋标记(3D-ASL)和体素内不相干运动成像(IVIM)这3种反映肿瘤组织灌注情况的影像学指标对胶质母细胞瘤预后的预测价值。方法纳入2016年8月至2017年10月住院治疗的34例胶质母细胞瘤患者,根据总生存期分为14个月组(17例)和≥14个月组(17例),术前行MRI常规扫描,以及DSC-MRI、3D-ASL、IVIM扫描,于肿瘤强化区域和强化肿瘤瘤周区域勾画兴趣区,记录DSC-最大相对脑血容量(rCBVmax)值和相对脑血流量(r CBF)值、ASL-脑血流量(CBF)值、IVIM-灌注分数(PF)值,绘制受试者工作特征曲线(ROC曲线)评价各项影像学指标对判断预后的参考价值。结果在肿瘤强化区域,总生存期14个月组与≥14个月组患者ASL-CBF值、IVIM-PF值、DSC-rCBF值、DSC-rCBVmax值差异无统计学意义(均P 0.05);在强化肿瘤瘤周区域,总生存期14个月组患者IVIM-PF值低于(P=0.011)、DSC-rCBF值(P=0.009)和DSC-rCBVmax值(P=0.012)高于≥14个月组。绘制强化肿瘤瘤周区域ASL-CBF值、DSC-rCBF值和DSC-rCBVmax值的ROC曲线,曲线下面积分别为0.579(95%CI:0.372～0.787,P=0.453)、0.763(95%CI:0.588～0.937,P=0.013)和0.746(95%CI:0.565～0.926,P=0.020),提示DSC-rCBF值和DSC-rCBVmax值对预后判断的参考价值更佳。结论 DSC-rCBF值和DSC-rCBVmax值对胶质母细胞瘤的预后判断的参考价值更佳,而ASL和IVIM序列未显示出较好的预后判断价值。     

Intracellular perfusion

The method of intracellular perfusion (or dialysis) has been used to replace the cytoplasm of vertebrate and invertebrate neurones (diameter > 10 μm) with saline whilst maintaining the integrity of the cell membrane. With this technique it has been possible to study the fast kinetics of ionic and gating currents and to record ionic currents in patches (10–30 μm²) of cell membrane. The patch recordings were characterized by high signal:noise ratios.     

CT perfusion in acute stroke

As new treatments are developed for stroke, the potential clinical applications of CT perfusion (CTP) imaging in the diagnosis, triage, and therapeutic monitoring of these diseases are certain to increase. Technical advances in scanner hardware and software should no doubt continue to increase the speed, coverage, and resolution of CTP imaging. CTP offers the promise of efficient use of imaging resources and, potentially, of decreased morbidity. Most importantly, current CT technology already permits the incorporation of CTP as part of an all-in-one acute stroke examination to answer the four fundamental questions of stroke triage quickly and accurately, further increasing the contribution of imaging to the diagnosis and treatment of acute stroke.     

Cerebral perfusion abnormalities in abstinent cocaine abusers: a perfusion MRI and SPECT study

Nuclear medicine studies found decreased regional cerebral blood flow (rCBF) in the cortex and deep gray matter of cocaine users. Perfusion magnetic resonance imaging (MRI), a non-radioactive technique, has not been applied to evaluate persistent rCBF abnormalities. Twenty-five abstinent cocaine users and 15 healthy subjects without a history of drug use were examined with perfusion MRI, using dynamic bolus-tracking, and single photon emission computed tomography (SPECT), using 133Xe-calibrated 99mTc-HMPAO. After coregistration of SPECT with MRI, the relative rCBF (from perfusion MRI and SPECT) and absolute rCBF (from SPECT) were determined in 10 brain regions in each hemisphere. There was a statistically significant interaction between drug use and brain region on SPECT alone (relative and absolute rCBF), and on SPECT and perfusion MRI combined, but not on perfusion MRI alone. There also was a significant interaction among gender, drug use, and brain region. Compared to the control subjects, cocaine users showed increased rCBF in the frontal white matter (+8.6%, P=0.02) and in the globus pallidus (+6.3%, P=0.05), and decreased rCBF in the putamen (-3.9%, P=0.04) and the temporal cortex (-2.4%, P=0.02). SPECT and perfusion MRI detect a regional pattern of rCBF abnormalities in cocaine users that is consistent across the two methods. The hypoperfusion in the cortex and deep gray matter of the cocaine users is consistent with previous results. The increased rCBF in the white matter of cocaine users may be due to the presence of reactive glia.     

CT perfusion imaging in acute stroke

Computed tomographic perfusion (CTP) imaging is an advanced modality that provides important information about capillary-level hemodynamics of the brain parenchyma. CTP can aid in diagnosis, management, and prognosis of acute stroke patients by clarifying acute cerebral physiology and hemodynamic status, including distinguishing severely hypoperfused but potentially salvageable tissue from both tissue likely to be irreversibly infarcted ("core") and hypoperfused but metabolically stable tissue ("benign oligemia"). A qualitative estimate of the presence and degree of ischemia is typically required for guiding clinical management. Radiation dose issues with CTP imaging, a topic of much current concern, are also addressed in this review.     

Cerebral cortex perfusion rates in dementia

Cerebral cortex perfusion rates (CPR) were measured in 11 patients with dementia. In six patients the dementia appeared to be due to a primary neuronal degeneration and in the remainder it appeared to be secondary to vascular disease. In the context of blood flow measurement, it is suggested that the terms primary and secondary dementia are preferable to the terms presenile and senile dementia, because the latter are classified by age alone and the terms have no aetiological or pathological significance. The perfusion rates in patients with primary dementia were within normal limits for their age, whereas those in patients with secondary dementia were significantly reduced. This difference is likely to apply only if the measurements are made early in the course of the disease.     

Hippocampal perfusion in mild Alzheimer's disease

Perfusion and metabolic studies in patients with Alzheimer's disease (AD) have so far yielded conflicting results on the functional status of the hippocampal region, whose deep location in the brain makes it critical to optimize the image-reconstruction technique employed in emission tomography. We used a brain-dedicated device (CERASPECT) to perform single photon emission computed tomography (SPECT) studies with 99mTc-hexamethylpropylene-amine-oxime in 22 consecutive patients (mean age: 74+/-6.5 years) with mild [mini-mental status examination (MMSE) score > or =15, mean 20.8+/-3.2], probable AD. The control subjects were 11 healthy elderly people (mean age: 70.5+/-6.5 years). In patients, the total score on the selective reminding test (SRT) was used as an index of memory function. Counts from a hippocampal and a temporoparietal region of interest in each hemisphere were referred to the average thalamic counts. To optimize SPECT images, we used conventional filtered back-projection (FBP) reconstruction and a new iterative method of conjugate gradients (CG), which takes into account the geometrical and physical characteristics of the gamma-camera. Hippocampal perfusion in the two hemispheres was significantly lower in patients than in control subjects, regardless of which reconstruction method was used, and correlated with the MMSE score. The correlation between hippocampal perfusion and the SRT score was significantly (bootstrap procedure) higher with the CG method than with the FBP method (CG: r=0.52 and 0.54; FBP: r=0.39 and 0.47, for the right and left hemisphere, respectively). These results show hippocampal hypoperfusion in patients with mild AD, a correlation between hippocampal perfusion and the severity of cognitive impairment, and enhanced identification of these subtle perfusional changes with the use of an alternative image-reconstruction method that improves the spatial resolution of SPECT images.     

Ventriculo-lumbar perfusion in acute ischemic stroke

Introduction  Effective treatment for severe ischemic stroke continues to be largely an unmet medical need. Using a nonvascular (paravascular cerebrospinal fluid) pathway to provide oxygen and nutrients to ischemic tissues may be a means of treating this disease. The primary objective of this study was to evaluate the safety and technical feasibility of ventriculo-lumbar perfusion with the oxygenated fluorocarbon nutrient emulsion (OFNE) perfusion system in the treatment of patients with severe hemispheric cerebral ischemia. Results  Four patients were enrolled in this pilot study. At admission, patients' National Institutes of Health Stroke Scale scores ranged from 16 to 24. The perfusion pathway was successfully established in all four patients. Maximum perfusion rates varied from 25 to 40 mL/minute; total volume perfused over the 24-hour period ranged from 30.6 to 45.8 L. ICP ranged from −3 to 16 mmHg during the perfusion. The 24-hour perfusion was successfully completed in all four patients with no serious adverse events during the perfusion. Conclusion  It is technically feasible and safe to establish a ventriculo-lumbar perfusion pathway using a specially designed lumbar drainage catheter and to control intracranial pressure while perfusing large volumes of OFNE.