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临床研究
FLAIR血管高信号在评估未再灌注治疗的卒中预后中的价值
黄红涛 靳明旭 彭明洋 殷信道 王薇

Cite this article as: Huang HT, Jin MX, Peng MY, et al. The value of FLAIR vascular hyperintensity in evaluating the outcome of stroke after non-reperfusion therapy. Chin J Magn Reson Imaging, 2020, 11(1): 6-10.本文引用格式:黄红涛,靳明旭,彭明洋,等. FLAIR血管高信号在评估未再灌注治疗的卒中预后中的价值.磁共振成像, 2020, 11(1): 6-10. DOI:10.12015/issn.1674-8034.2020.01.002.


[摘要] 目的 探讨液体衰减反转恢复序列血管高信号(fluid-attenuated inversion recovery vascular hyperintensity,FVH)在未接受再灌注治疗的轻度症状大脑中动脉闭塞的卒中患者预后中的价值。材料与方法 前瞻性纳入2017年1月至2019年3月在本院就诊的具有轻度症状的急性卒中患者[入院美国国立卫生研究院卒中量表(National Institute of Health stroke scale;NIHSS)评分≤5分]。所有患者均于治疗前接受磁共振成像检查,且经磁共振血管造影(MR angiography,MRA)检查为大脑中动脉闭塞。根据FVH显著存在与否,将FVH分为两组:FVH (-)和FVH (+)组。收集所有患者的弥散张量成像(diffusion-weighted imaging,DWI)梗死体积、3个月功能功能预后(mRS评分)及一般临床资料等。统计学分析FVH在未接受再灌注治疗的轻度症状大脑中动脉闭塞的卒中患者预后中的价值。结果 在未接受再灌注治疗的患者中(48例),FVH (-)组FVH-DWI不匹配率(23.81 %)、不良功能预后比例(14.29%)低于FVH (+)组(66.67%;51.85%),差异有统计学意义(t=8.694,P=0.004;t=7.288,P=0.014)。与预后良好组相比,不良功能预后组具有较低的FVH-DWI不匹配率(23.81%与61.29%)、较大的DWI梗死体积(6.60±1.11与4.43±2.20)及较高的FVH (+)率(82.35%与41.94%),差异有统计学意义(t=6.273 ,P=0.017;t=4.447,P=0.000;t=7.288,P=0.014)。逻辑回归分析结果显示DWI梗死体积[OR (95%CI)] :0.327 [(0.154~ 0.698),P=0.004]、FVH [OR (95%CI)] :6.462[(1.536~27.179),P=0.011]及FVH-DWI不匹配[OR (95%CI)]:0.099 [(0.025~0.389),P=0.001 ]为预测未接受再灌注治疗患者卒中预后的独立预测因子。结论 对于未接受再灌注治疗的轻度症状大脑中动脉闭塞的卒中患者,FVH显著比FVH不显著的患者更可能出现不良的功能预后。
[Abstract] Objective: To investigate the prognostic value of fluid-attenuated inversion recovery vascular hyperintensity (FVH) in outcome of stroke patients with mild symptoms and middle cerebral artery occlusion after non-reperfusion therapy.Materials and Methods: The stroke patients with mild symptoms [National Institute of Health stroke scale (NIHSS)≤5 score] who were admitted to our hospital from January 2017 to March 2019 were rolled prospectively. All patients underwent magnetic resonance imaging (MRI) before therapy and were diagnosed as middle cerebral artery occlusion in MR angiography (MRA). According to the presence or absence of FVH, FVH was divided into two groups: FVH (-) and FVH (+). Diffusion weighted imaging (DWI), infarct volume, 3-month functional outcome (mRS score) and clinical data were collected. Statistical analysis was performed to evaluate the prognostic value of FVH in outcome of stroke patients with mild symptoms and middle cerebral artery occlusion after non-reperfusion therapy.Results: In patients with non-reperfusion therapy (n=48), the FVH-DWI mismatch rate (23.81%), the poor outcome (14.29%) in FVH (-) group were lower than those in FVH (+) group (66.67%; 51.85%), and the difference was significant (t=8694, P=0.004; t=7.288, P=0.014). Compared with the good outcome group, the poor outcome group had lower FVH-DWI mismatch rate (23.81% vs 61.29%), larger DWI infarct volume (6.60±1.11 vs 4.43±2.20) and higher FVH (+) rate (82.35% vs 41.94%), there were significant difference (t=6.273, P=0.017; t=4.447, P=0.000; t=7.288, P=0.014). Logistic regression analysis showed that DWI infarct volume [OR (95% CI)]: 0.327 [(0.154-0.698), P=0.004], FVH [OR (95%CI)]: 6.462 [(1.536—27.179), P=0.011] and FVH-DWI mismatch [OR (95% CI)]: 0.099 [(0.025-0.389), P=0.001] were independently factors in outcome of stroke patients with non-reperfusion therapy.Conclusions: For stroke patients with mild symptoms and middle cerebral artery occlusion with non-reperfusion therapy, those with prominent FVH are more likely to have poor outcome than those without prominent FVH.
[关键词] 卒中;磁共振成像;预后;液体衰减反转恢复序列血管高信号
[Keywords] stroke;magnetic resonance imaging;prognosis;fluid-attenuated inversion recovery vascular hyperintensity

黄红涛 南京医科大学附属南京医院(南京市第一医院)医学影像科,南京 210006

靳明旭 南京医科大学附属南京医院(南京市第一医院)医学影像科,南京 210006

彭明洋 南京医科大学附属南京医院(南京市第一医院)医学影像科,南京 210006

殷信道 南京医科大学附属南京医院(南京市第一医院)医学影像科,南京 210006

王薇* 南京医科大学附属南京医院(南京市第一医院)医学影像科,南京 210006

通信作者:王薇,E-mail:vikeywang@sina.com

利益冲突:无。


基金项目: 江苏省科技发展计划项目 编号: BE2017614
收稿日期:2019-08-19
接受日期:2019-11-21
中图分类号:R445.2; R743.33 
文献标识码:A
DOI: 10.12015/issn.1674-8034.2020.01.002
本文引用格式:黄红涛,靳明旭,彭明洋,等. FLAIR血管高信号在评估未再灌注治疗的卒中预后中的价值.磁共振成像, 2020, 11(1): 6-10. DOI:10.12015/issn.1674-8034.2020.01.002.

       超过一半的缺血性脑卒中患者会有轻度的神经功能缺损临床综合征[1]。尽管最初症状轻微,仍然有相当大比例的患者随后可发展为残疾[2]。大动脉闭塞是卒中早期神经功能恶化或预后不良的重要影响因素[2,3,4]。因此,早期评估大动脉闭塞引起的轻度卒中患者不良预后的影响因素很有必要。液体衰减反转恢复血管高信号(fluid-attenuated inversion recovery vascular hyperintensity,FVH)是FLAIR序列上病灶侧出现的迂曲蛇形、管状或点状沿血管走形的高信号影,由脑膜动脉的缓慢逆流导致[5]。FVH常出现在大血管闭塞疾病中[6,7] ,在脑血管再灌注后,FVH通常减少或消失[5]。因此,它可能是逆行软脑膜侧支血流的影像学标志。在轻度症状的大动脉闭塞卒中患者中,FVH的临床意义尚不清楚。本研究旨在探讨FVH在未接受再灌注治疗的轻度症状大脑中动脉闭塞的卒中患者预后中的价值。

1 材料与方法

1.1 研究对象

       连续纳入2017年1月至2019年3月在南京市第一医院就诊的具有轻度症状的急性卒中患者[入院美国国立卫生研究院卒中量表[National Institute of Health stroke scale,NIHSS)评分≤5分],经磁共振血管造影(MR angiography ,MRA)检查为大脑中动脉闭塞。急性卒中定义为DWI上有脑梗死表现的急性临床血管综合症。所有患者均按照急性缺血性卒中管理指南进行治疗。符合静脉溶栓治疗的患者在CT扫描后进行静脉溶栓治疗(Alteplase ,rtPA)后,立即行MRI检查。若MRA发现大血管闭塞且符合血管内取栓的患者则立马行血管内取栓治疗。未接受再灌注治疗定义为未接受溶栓治疗及血管内取栓治疗。纳入标准:(1)首次急性中卒中,或以前发生过卒中但没有遗留影响神经评分的后遗症;(2)发病时间为24 h以内;(3)入院NIHSS评分≤5分;(4)治疗前行MRI检查(DWI、FLAIR、MRA)且影像可用于评估(无明显运动伪影等);(5)有3个月的改良mRS评分(modified Rankin scale,mRS)。排除标准:(1)颅内出血、肿瘤或创伤;(2)有MRI禁忌证;(3)缺失3个月mRS评分;(4)入院NIHSS评分>5分;(5) MRI或DSA有运动伪影图像无法评估。共120例符合纳入标准,男94例,女26例,平均年龄(69.18±11.94)岁。

       收集患者的性别、年龄、高血压、糖尿病、高血脂、高同型半胱氨酸、房颤、入院及出院NIHSS评分;卒中患者预后用3个月的mRS评分评估,mRS在0~ 2者为预后良好组,mRS在3~ 6者为预后不良组。本研究经南京市第一医院伦理委员会批准,所有病人签署知情同意书。

1.2 检查方法

       采用3.0 T MR扫描设备(Ingenia, Philips Medical Systems, Netherlands)进行治疗前、治疗后检查。MRI扫描序列包括FLAIR、DWI、MRA。扫描参数如下。FLAIR:反转恢复序列,TR 7000 ms,TE 120 ms,矩阵356×151,视野(FOV) 230 mm×230 mm,翻转角(FA) 90° ,层数18,层厚6 mm,层间距1.3 mm;DWI:自旋回波序列,TR 2501 ms,TE 98 ms,矩阵152×122 ,3个方向,FOV 230 mm×230 mm,翻转角(FA) 90° ,层数18,层厚6 mm,层间距1.3 mm ,b=0、1000 s/mm2;MRA:快速场回波序列,TR 4.9 ms ,TE 1.82 ms,矩阵528×531,FOV 330 mm×330 mm,层厚1.2 mm。

1.3 影像分析

       由2名有经验的神经放射学诊断医师采用双盲法对所有影像资料进行分析,结果不一致时经协商后达成一致。FVH表现为FLAIR序列上病灶侧出现的迂曲蛇形、管状或点状沿血管走形的高信号影[6]。明显的远端FVH定义为超过1/3的MCA区域存在FVH[8]。根据FVH显著存在与否,将FVH分为两组:FVH (-)和FVH (+)组。在FVH和DWI轴位图像上评估FVH-DWI不匹配。当FVH超出DWI病灶损伤的边界时则认为存在FVH-DWI不匹配。无FVH-DWI不匹配定位为无FVH存在或所有FVH都位于DWI病灶区域内。在飞利浦3.0 T MR自带的后处理工作站测量DWI体积。在后处理工作站上对DWI图像上梗死高信号区进行感兴趣区勾画,自动计算DWI梗死体积。根据MRA图确定与病变相关的闭塞位置,动脉闭塞定义为远端血流信号消失。MCA闭塞位置分为M1近端、M1远端及M2段。

1.4 统计学分析

       应用SPSS 19.0统计学软件进行数据处理。计量资料采用均数±标准差(±s)表示,计数资料采用例(%)表示。采用独立t检验或卡方检验对资料进行统计学分析。应用多元逻辑回归分析参数(P<0.05)在预测卒中预后中的价值。P <0.05为差异有统计学意义。

2 结果

2.1 FVH(-)与FVH (+)病人间各参数比较

       120例患者中未接受再灌注治疗患者48例,其中FVH (-)21例,FVH (+)27例;接受再灌注治疗患者72例,其中FVH (-)28例,FVH (+)44例。在未接受再灌注治疗的患者中,FVH (-)组DWI梗死体积[(5.36±1.18) mm3]小于FVH (+)组[(5.39±2.62) mm3],然而两者间无明显统计学差异(t=-0.052;P=0.962)。FVH (-)组FVH-DWI不匹配率(23.81%)、不良功能预后比例(14.29%)低于FVH(+)组(66.67%;51.85%),差异有统计学意义(t=8.694 ,P=0.004;t=7.288,P=0.014)。两组间年龄、性别、危险因素、发病至MRI检查时间、入院NIHSS评分及大脑中动脉闭塞位置无明显差异(P>0.05)。在接受再灌注治疗的患者中,FVH (-)组FVH-DWI不匹配率(39.29%)低于FVH (+)组(79.55%),差异有统计学意义(t=12.021;P=0.001)。FVH (-)组不良功能预后比例(53.57%)高于FVH (+)组(36.36%),差异无统计学意义(t=2.067 ;P=0.222)(表1表2)。

表1  未再灌注治疗患者FVH (+)与FVH (-)间各参数比较
Tab. 1  Comparison of parameters between FVH (+) and FVH(-) in patients with non-reperfusion therapy
表2  再灌注治疗患者FVH (+)与FVH (-)间各参数比较
Tab. 2  Comparison of parameters between FVH (+) and FVH (-) in patients with reperfusion therapy

2.2 未接受再灌注治疗组不良功能预后与良好功能预后各参数比较

       48例未接受再灌注治疗的患者中,不良功能预后17例,良好功能预后31例。与预后良好组比,不良功能预后组具有较低的FVH-DWI不匹配率(23.81%与61.29%)、较大的DWI梗死体积[(6.60±1.11) mm3]与[(4.43±2.20) mm3]及较高的FVH (+)率(82.35%与41.94%),差异有统计学意义(t=6.273 ,P=0.017 ;t=4.447,P=0.000;t=7.288,P=0.014)(图1图2)。两组间年龄、性别、危险因素、发病至MRI检查时间、入院NIHSS评分及大脑中动脉闭塞位置无明显差异(P > 0.05)(表3)。

图1  男,67岁,因“右侧肢体无力1.5 h”入院,入院NIHSS评分4分,未行再灌注治疗。DWI (A、B)示左侧基底节区及左侧脑室旁见斑片状高信号影,为急性脑卒中,FLAIR (C、D)未见明显的血管高信号影,3个月mRS评分1分,预后良好
图2  男,63岁,因“右侧肢体无力2 h”入院,入院NIHSS评分5分,DWI (A、B)示左侧脑室旁见斑片状高信号影,为急性脑卒中,FLAIR (C、D)见明显的血管高信号影(箭头),3个月mRS评分3分,预后不良
Fig. 1  A 67-year-old male, right limb weakness for 1.5 hours, the NIHSS score on addimission was 4 score, and no reperfusion therapy was performed. DWI (A, B) showed patchy high signal in the left basal ganglia and paraventricular, which was acute stroke. There was no obvious high signal in FLAIR (C, D). The outcome at 3-month was good (the mRS score was 1 score).
Fig. 2  A 63-year-old male, right limb weakness for 2 hours, the NIHSS score on admission was 5 score, and no reperfusion therapy was performed. DWI (A, B) showed patchy high signal in the left basal paraventricular, which was acute stroke. There was obvious high signal in FLAIR (C, D; arrow). The outcome at 3-month was poor (the mRS score was 3 score).
表3  未接受再灌注治疗组不良功能预后与良好功能预后各参数比较
Tab. 3  Comparison of parameters between good outcome and poor outcome in patients with non-reperfusion therapy

2.3 参数(P <0.05)预测未接受再灌注治疗卒中预后的多元逻辑回归分析

       将DWI梗死体积、FVH及FVH-DWI不匹配作为变量纳入多元逻辑回归分析,选择向前的条件进行分析,逻辑回归分析结果显示DWI梗死体积[OR (95%CI): 0.327 (0.154~0.698);P=0.004]、FVH [OR (95%CI): 6.462 (1.536~ 27.179);P=0.011]及FVH-DWI不匹配[OR(95%CI):0.099 (0.025~ 0.389);P=0.001]为预测未接受再灌注治疗患者卒中预后的独立预测因子。

3 讨论

       FVH常见于颅内大血管闭塞或严重狭窄的病人,约45%的卒中患者在神经症状出现后24 h内的MRI图像上可出现FVH[9],其MRI表现的机制及临床意义一直存在争议。有学者通过对血管造影研究显示FVH可能反映了脑膜动脉侧支循环的缓慢动脉血流[10],从而导致“血流空洞”的丧失和FLAIR序列上信号增加。也有学者认为FVH代表急性卒中患者由于大动脉闭塞导致血流动力学受损和逆行的侧支血流[9]。然而,目前FVH对卒中的预后价值仍存在争议[11,12,13,14]

       以往的研究多集中在大动脉闭塞且接受再灌注治疗的患者,一些研究包括了所有急性卒中患者,而未考虑大动脉闭塞,或仅统计了是否存在FVH,而没有统计FVH数量。在这些研究中,结果显示FVH可预测近段大脑中动脉闭塞卒中患者的功能预后[14,15,16]。本研究评估了轻度症状大脑中动脉闭塞卒中患者FVH与功能预后间的关系,并将其分为接受再灌注治疗组与未接受再灌注治疗组,分别比较FVH与功能预后间的关系。对于接受再灌注治疗的患者,FVH (-)组的DWI梗死体积稍大于FVH (+),不良功能预后比例(53.57%)高于FVH (+)组(36.36%),然而,两组间无明显统计学差异。FVH作为缺血半暗带的替代标记物,与大动脉闭塞患者再灌注治疗后的良好预后相关[6,12,13]。一些研究报道显示在近段大脑中动脉闭塞的再灌注治疗超急性卒中患者中,明显的FVH是预后良好的早期标志[6,13]。与未接受再灌注治疗不同,再灌注治疗有可能减少显著FVH患者的不匹配区域。因此,FVH作为缺血半暗带的标志,可能是未接受再灌注治疗患者的不良预后或再灌注治疗患者良好预后的标志[17]。然而,本研究没有发现再灌注治疗患者中显著的FVH与卒中预后间的相关性研究,这可能与样本异质性有关。

       对于未接受再灌注治疗的患者,FVH (-)组DWI梗死体积小于FVH (+)组,尽管这在统计学上并没有意义,不良功能预后比例(14.29%)低于FVH (+)组(66.67%;51.85%),差异有统计学意义。FVH代表了逆行的脑膜侧支循环,是超急性期灌注-弥散不匹配的替代标志物[6,18]。如果血流足以克服灌注不足,外周侧支循环可以延长组织存活时间。然而,FVH也代表了缓慢的血管流动,不充分的侧支循环区域随着时间的推移可能发展为梗死增长[11,19]。在本研究中尽管存在大动脉闭塞,但由于NIHSS≤5分,卒中患者的DWI梗死体积均较小,显著的FVH可能代表了较小的DWI梗死体积和较大的失匹配区域。这就解释了为什么FVH显著的患者在不接受再灌注治疗时更有可能出现FVH-DWI不匹配和不良功能预后。逻辑回归分析结果显示DWI梗死体积、FVH及FVH-DWI不匹配为预测未接受再灌注治疗患者卒中预后的独立预测因子。可见,在未接受再灌注治疗的大血管闭塞的卒中患者中,FVH的存在更可能出现预后不良。

       本研究存在一定的局限性。首先,本研究为单中心研究,样本量较少,患者选择可能存在偏差。其次,本研究未定量灌注-弥散不匹配,然而,FVH-DWI不匹配可作为预测灌注-弥散不匹配存在的一种简单方法。

       综上所述,对于未接受再灌注治疗的轻度症状大脑中动脉闭塞的卒中患者,FVH显著比FVH不显著的患者更可能出现不良的功能预后。

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