高信号血管征在急性缺血性卒中的诊断价值

目的 探讨急性脑卒中患者磁共振液体反转恢复序列(flair)中高信号血管征(HVS)在诊断急性缺血性卒中脑组织病变中的价值。方法 选取139例大脑中动脉供血区急性缺血性卒中患者MRI资料。将不同发病时间段(<6 h,6～24 h,> 24 h)的患者,根据有无HVS分为HVS阳性组和HVS阴性组,测量各组梗死灶中心较对侧正常区域的相对ADC值[rADC(中心)],对MRA的大脑中动脉的梗死程度进行量化评分、同时收集各组病例NIHSS评分,比较各发病时间段内HVS阳性组和HVS阴性组在rADC(中心)、MRA评分及NIHSS评分的差异。结果 发病6 h内的患者,HVS阳性组rADC(中心)为0.495±0.094,HVS阴性组rADC(中心)为0.600±0.138,两组数据差异有统计学意义(P <0.05),当发病时间>6 h时,两组数据中rADC(中心)差异无统计学意义(P>0.05)。发病时间<24 h的患者,HVS阳性组和HVS阴性组之间NIHSS评分有统计学意义(P <0.05),当发病时间> 24 h时两组数据NIHSS评分差异...     

多期CT血管成像对急性缺血性卒中血管内治疗短期预后的价值

目的：探讨多期CT血管成像对急性缺血性卒中（AIS）血管内治疗短期预后的价值。方法：回顾性分析183例接受血管内治疗的AIS患者,按随访90 d改良Rankin量表（mRS）评分分为预后良好（mRS评分≤2）组和预后不良（mRS评分>2）组。通过改良Tan评分评估多期CT血管成像显示的侧支循环情况,侧支循环不良为闭塞大脑中动脉区域的侧支循环小于对侧1/2,侧支循环良好为闭塞大脑中动脉区域的侧支循环大于对侧1/2。采用多变量logistic回归,曲线下面积（AUC）评价模型性能,DeLong检验比较AUC间的差异。结果：Logistic回归显示,较低入院NIHSS评分和动脉晚期侧支循环良好是AIS患者短期预后良好的独立预测因素,AUC分别为0.72 (0.65～0.79)和0.75 (0.68～0.81)。两者联合时AUC可达0.79,显著高于单一预测因素（DeLong检验,均P<0.05）。结论：动脉晚期侧支循环良好和较低入院NIHSS评分是血管内治疗短期预后良好的独立预测因素。联合预测模型具有较高的诊断效能,可为临床治疗方案选择提供参考。     

急性缺血性脑卒中病人FLAIR血管高信号与预后的相关性研究

目的探讨急性缺血性脑卒中病人液体衰减反转恢复(FLAIR)序列血管高信号(FHV)与临床预后是否有关。方法前瞻性纳入北京天坛医院2012年1月—2015年12月的急性缺血性脑卒中绿色通道病人39例,男25例,女14例,平均年龄(59.79±12.99)岁。病人均接受了基线MRI检查,包括扩散加权成像(DWI)、MR血管成像(MRA)和FLAIR,36例病人进行了7 d MRI随访,38例进行了90 d改良Rankin量表(m RS)评估。病人根据7 d MRA表现分为血管再通组与血管未再通组,根据90 d m RS评分分为结局良好组和结局不良组。评价基线FHV的分布范围及7 d复查FHV是否消失,采用Fisher精确检验分析比较7 d血管再通组与血管未再通组之间FHV消失的情况,结局良好组与结局不良组FHV分布范围。结果共评价36例病人7 d随访结果 ,其中血管再通组24例,血管未再通组12例。18例FHV消失,其中17例发生在血管再通组(17/24例,70.83%);1例发生在血管未再通组(1/12例,8.33%),差异有统计学意义(P0.01)。共评价38例病人90 d m RS,其中结局良好组29例,结局不良组9例。2组间FHV分布层面、FHV ASPECTS评分差异均无统计学意义(P0.05)。结论基线FHV的分布范围不能预测90 d临床预后是否良好,但是FHV消失意味着血管再通。     

血管内磁共振成像及治疗

血管内磁共振成像是通过穿刺将线圈插入血管内进行靶血管成像的技术,可以对深部动脉进行高分辨力成像;利用血管内磁共振线圈的引导,通过磁共振实时成像可进行血管介入治疗和基因治疗。综述血管内磁共振成像和治疗的研究进展。     

FLAIR序列远端高信号血管征对急性脑梗死体积的预测作用

目的探讨脑梗死患者磁共振液体衰减反转恢复序列(fluid-attenuated inversion recovery,FLAIR)成像高信号血管征(hyperintense vessel sign,HVS)对急性脑梗死体积的预测作用。方法根据是否存在远端HVS,分为HVS组(n=15)和无HVS组(n=31),比较两组患者扩散加权成像(DWI)上所示梗死体积大小是否有差异。结果入组46例患者中,有15例患者FLAIR序列上可见远端HVS(32.6%)。测量HVS组与无HVS组患者梗死体积的大小,HVS组患者梗死体积(82.32±30.68)mm3,无HVS组患者梗死体积为(100.85±31.24)mm3,两组比较(t=4.895,P=0.039),差异具有统计学意义。结论 FLAIR上HVS的出现代表梗死后缺血区周围侧支循环的建立,与患者急性期梗死体积有一定的相关性,有助于预测脑梗死患者的预后。     

足月新生儿动脉缺血性脑梗死早期磁共振成像特点

目的：探讨足月新生儿动脉缺血性脑梗死（NAIS）的早期MRI特点及不同MRI序列在NAIS的诊断价值。方法：回顾性分析2008年8月-2012年8月本院新生儿科收治的15例行MRI检查确诊的足月NAIS患儿的临床及MRI资料。15例患儿于出生后2～7d进行了头部MRI扫描,包括常规MRI及DWI检查,7例患儿同时行TOF—MRA检查。结果：15例NAIS患儿常规MRI中,14例T1WI呈异常信号,4例表现为受累区域弥漫低信号,10例稍低信号;15例T2WI呈异常信号,11例受累区域弥漫高信号,4例稍高信号,且灰白质分界不清。15例患儿首次DWI检查中均出现异常高信号,病灶边缘的较常规MRI清晰,DWI还显示了常规MRI未显示的胼胝体膝部、压部、丘脑及内囊后肢大脑脚等部位受累。7例患儿MRA检查中,6例出现梗死区域大脑中动脉（MCA）皮质分支增多增粗现象。结论：常规MRI可协助了解NAIS病程,DWI检查可早期诊断NAIS,并能清楚显示大脑深部小病灶的受累情况,尤其是皮质脊髓束的受累。NAIS早期MRA大多显示病变区MCA分支增多,与成人脑梗死的血管狭窄或完全闭塞不同。     

FLAIR血管高信号征对急性缺血性脑卒中的临床预后及侧支循环的相关性研究

目的探讨单侧大脑中动脉供血区急性缺血性脑卒中患者MRI-FLAIR序列血管高信号(FVH)与患者侧支循环及临床预后的关系。方法选取因大脑中动脉闭塞导致急性脑梗塞患者82例,FVH征阳性者70例,收集患者基本临床资料,根据MRI-FLAIR及CTP图进行FVH评分和侧支血管分级,根据90天mRS评分分为预后良好组(mRS≤2分)及预后不良组mRS(3~6)分。采用Pearson相关分析评估FVH与90天mRS评分及梗死面积的相关关系,Spearman秩相关检验评估FVH与侧支血管评分的相关关系;采用单因素分析、多变量二元Logistic回归分析及ROC曲线分析,探讨影响AIS患者预后相关因素。结果Spearman秩相关检验结果显示FVH评分与侧支血管评分呈正相关关系,Pearson分析结果显示FVH与90天mRS评分及梗死面积呈负相关关系。多变量二元Logistic回归分析的结果显示,FVH评分、侧支血管评分和梗死体积与AIS患者的预后相关,差异有统计学意义。FVH评分高的患者具有更小的梗死体积和更好地临床预后。结论FVH评分与侧支血管评分呈正相关关系,FVH评分可表示侧支循环情况;FVH评分与90天mRS评分、梗死体积呈负相关。FVH可预示临床预后。     

常规磁共振及磁共振波谱成像评估新生儿缺氧缺血性脑病严重程度

目的 探讨常规磁共振成像(MRI)和氢质子磁共振波谱成像(1H-MRS)评估足月新生儿缺氧缺血性脑病(HIE)严重程度的诊断价值.方法 前瞻性研究78例HIE患儿,按临床标准分为轻度组(42例)、中度组(17例)和重度组(19例),20例正常足月新生儿作为对照组.行常规MRI检查和TE 135 ms、TE 35 ms ...     

Advanced imaging application for acute ischemic stroke

With the approval of intravenous recombinant tissue plasminogen activator (r-TPA) in 1995, acute ischemic stroke therapy is increasingly being administered. Currently the approach to imaging these patients is very simplistic. Typically, noncontrast head computed tomography (CT) is the only study performed prior to treatment. Advanced imaging using CT or magnetic resonance imaging (MRI) can play a very important role in the triage and classification of patients with acute ischemic stroke. With knowledge of the location and size of the occlusion as well as the collateral circulation, the best treatment can be selected, minimizing any morbidity from treatment and maximizing the chance of success. The identification and stratification of patients according to their imaging and clinical features will further individualize treatment and allow tailored therapy. This review will discuss rapid imaging techniques that are easily available and the rationale for their use.     

磁共振测定颈动脉粥样硬化特征与急性脑梗死的关系

目的:应用3.0T磁共振测定颈动脉斑块负荷、成分与急性脑梗死的发生及梗塞体积的相关性。方法:对62例急性颈内动脉供血区脑梗死患者行颈动脉血管壁磁共振检查,测量颈动脉管腔狭窄率和斑块负荷(最大管壁厚度及管壁体积标准化指数),评价斑块成分(坏死脂核,出血,钙化及纤维帽破裂),测得DWI急性脑梗死体积,计算OR值和Spearman秩相关系数。结果:症状侧颈动脉狭窄程度、最大管壁厚度、管壁体积标准化指数和斑块内出血、钙化和纤维帽破裂的发生率均高于非症状侧(P值均<0.05);症状侧颈动脉管壁体积标准化指数与同侧颈内动脉供血区急性脑梗死体积有较强的正相关(Spearman秩相关系数0.327,P<0.05)。斑块内出血和钙化是较强的急性脑梗死暴露因素(OR值分别为2.4和2.1,P值均<0.05)。结论:症状侧与非症状侧颈动脉斑块特征存在差异,且与急性脑梗死存在相关,提示这些特征可能为斑块不稳定重要因素。     

Effect of b value on contrast during diffusion-weighted magnetic resonance imaging assessment of acute ischemic stroke

PURPOSE: To examine the effect of varying the diffusion encoding strength (b value) on the contrast (signal difference, Delta S) between damaged and normal tissue during diffusion-weighted magnetic resonance imaging (DWI) assessment of acute ischemic stroke. MATERIALS AND METHODS: Phantoms with diffusion values approximating those expected in acutely infarcted and normal tissue were constructed from a mixture of agar and formaldehyde and imaged at varying b values (0-3000 mm(-2) second). Ten patients were imaged with multiple b values (500-2500 mm(-2) second) within 12 hours of stroke onset. RESULTS: Theoretical calculations showed that for any combination of diffusion coefficients there existed an optimal b value that was higher than the standard setting of 1000 mm(-2) second, and this was confirmed by the phantom studies. In the patients, increasing b from 1000 to 1500 mm(-2) second increased Delta S (average, 22.4%; P = 0.001), but no consistent benefit was seen at b = 2000 mm(-2) second (P = 0.408). This compared favorably with the average optimal b value of 1662 mm(- 2) second calculated from the patients. CONCLUSION: These results suggest that increasing the b value from 1000 to 1500 mm(-2) second would increase contrast between infarcted and normal tissue in the setting of acute ischemic stroke.     

人工智能在急性缺血性脑卒中成像中的应用进展

人工智能(AI)技术可采用多种算法模拟人类认知和信息处理过程,与CT和MRI相结合可用于急性缺血性脑卒中成像,包括梗死灶的检测、影像分割、头颈大血管闭塞的检测和病人预后预测等。采用AI技术分析或构建模型有助于临床医师对脑卒中病人的尽早诊疗、及时干预和随访评估。概述AI的概念,并就其在急性缺血性脑卒中病人CT平扫、CT血管成像(CTA)、CT灌注成像(CTP)、MRI中的应用进展进行综述。     

Association of carotid atherosclerotic plaque features with acute ischemic stroke: A magnetic resonance imaging study

Background and purpose

It remains unclear whether direct vessel wall imaging can identify carotid high-risk lesions in symptomatic subjects and whether carotid plaque characteristics are more effective indicators for cerebral infarct severity than stenosis. This study sought to determine the associations of carotid plaque characteristics by MR imaging with stenosis and acute cerebral infarct (ACI) sizes on diffusion weighted imaging (DWI).

Materials and methods

One hundred and fourteen symptomatic patients underwent carotid and brain MRI. ACI volume was determined from symptomatic internal carotid artery territory on DWI images. Ipsilateral carotid plaque morphological and compositional characteristics, and stenosis were also determined. The relationships between carotid plaque characteristics, stenosis and ACIs size were then evaluated.

Results

In carotid arteries with 30–49% stenosis, 86.7% and 26.7% were found to have lipid-rich necrotic core (LRNC) and intraplaque hemorrhage, respectively. Furthermore, 45.8% of carotid arteries with 0–29% stenosis developed LRNCs. Carotid morphological measurements, such as % wall volume, and the LRNC size were significantly associated with ipsilateral ACIs volume before and after adjustment for significant demographic factors (age and LDL) or stenosis in patients with carotid plaque (all p < 0.05).

Conclusions

A substantial number of high-risk plaques characterized by vessel wall imaging exist in carotid arteries with lower grade stenosis. In addition, carotid plaque characteristics, particularly the % wall volume and LRNC size, are independently associated with cerebral infarction as measured by DWI lesions. Our findings indicate that characterizing atherosclerotic plaque by MR vessel wall imaging might be useful for stratification of plaque risk and infarction severity.     

Identifying lesion growth with MR imaging in acute ischemic stroke

PURPOSE: To determine whether different MR diffusion- and perfusion-weighted imaging (DWI and PWI) parameters are important in distinguishing lesion growth from the acute lesion and from oligemia. MATERIALS AND METHODS: MR DWI and PWI were acquired from thirteen patients. We defined three regions: (i) LESION - intersection of acute and final lesions, (ii) GROWTH - portion of final lesion not part of acute lesion, and (iii) OLIGEMIA - region of perfusion abnormality not part of either the acute or final lesions. We used logistic regression modeling to distinguish GROWTH from LESION and from OLIGEMIA on a voxel-wise basis using DWI- and PWI-based parameters. Final models were selected based on the Wald statistic and validated by cross-validation using the mean (+/- standard deviation) area under the curve (AUC) from receiver operating characteristic analysis. RESULTS: The final model for differentiating GROWTH from LESION included DWI, the apparent diffusion coefficient (ADC), cerebral blood flow (CBF) and tissue type (AUC = 0.939 +/- 0.028). The final model for differentiating GROWTH from OLIGEMIA included DWI, ADC, CBF, and time-to-peak (AUC = 0.793 +/- 0.106). CONCLUSION: Different MR parameters are important in differentiating lesion growth from acute lesion and from oligemia in acute ischemic stroke.     

缺血性脑卒中的血氧水平依赖磁共振成像研究进展

缺血性脑卒中具有高发病率、高病死率、高致残率的特点[1],因而早期发现具有脑卒中风险的人群,并及时进行干预治疗,对脑卒中患者具有重要的意义。血氧水平依赖磁共振成像(blood-oxygenation-level-de-pendent MRI,BOLD MRI)可以反映局部脑组织氧代谢与氧供应间的差异,通过测量大脑氧代谢率和氧摄取分数,实现对脑缺血状态的监测,早期发现脑卒中并可以对治疗后的疗效进行评估。本文对缺血性脑卒中的 BOLD MRI 研究进展进行综述和讨论。