Three-dimensional arterial spin labeling and diffusion kurtosis imaging in evaluating perfusion and infarct area size in acute cerebral ischemia

BACKGROUND Early thrombolytic therapy is crucial to treat acute cerebral infarction,especially since the onset of thrombolytic therapy takes 1-6 h.Therefore,early diagnosis and evaluation of cerebral infarction is important.AIM To investigate the diagnostic value of magnetic resonance multi-delay threedimensional arterial spin labeling(3DASL)and diffusion kurtosis imaging(DKI)in evaluating the perfusion and infarct area size in patients with acute cerebral ischemia.METHODS Eighty-four patients who experienced acute cerebral ischemia from March 2019 to February 2021 were included.All patients in the acute stage underwent magnetic resonance-based examination,and the data were processed by the system’s own software.The apparent diffusion coefficient(ADC),average diffusion coefficient(MD),axial diffusion(AD),radial diffusion(RD),average kurtosis(MK),radial kurtosis(fairly RK),axial kurtosis(AK),and perfusion parameters post-labeling delays(PLD)in the focal area and its corresponding area were compared.The correlation between the lesion area of cerebral infarction under MK and MD and T2-weighted imaging(T2WI)was analyzed.RESULTS The DKI parameters of focal and control areas in the study subjects were compared.The ADC,MD,AD,and RD values in the lesion area were significantly lower than those in the control area.The MK,RK,and AK values in the lesion area were significantly higher than those in the control area.The MK/MD value in the infarct lesions was used to determine the matching situation.MK/MD<5 mm was considered matching and MK/MD≥5 mm was considered mismatching.PLD1.5s and PLD2.5s perfusion parameters in the central,peripheral,and control areas of the infarct lesions in MK/MD-matched and-unmatched patients were not significantly different.PLD1.5s and PLD2.5s perfusion parameter values in the central area of the infarct lesions in MK/MD-matched and-unmatched patients were significantly lower than those in peripheral and control areas.The MK and MD maps showed a lesion area of 20.08±5.74 cm^(2) and 22.09±5.58 cm^(2),respectively.T2WI showed a lesion area of 19.76±5.02 cm^(2).There were no significant differences in the cerebral infarction lesion areas measured using the three methods.MK,MD,and T2WI showed a good correlation.CONCLUSION DKI parameters showed significant difference between the focal and control areas in patients with acute ischemic cerebral infarction.3DASL can effectively determine the changes in perfusion levels in the lesion area.There was a high correlation between the area of the infarct lesions diagnosed by DKI and T2WI.

Arterial spin labeling in neuroimaging

Arterial spin labeling(ASL) is a magnetic resonance imaging technique for measuring tissue perfusion using a freely diffusible intrinsic tracer.As compared with other perfusion techniques,ASL offers several advantages and is now available for routine clinical practice in many institutions.Its noninvasive nature and ability to quantitatively measure tissue perfusion make ASL ideal for research and clinical studies.Recent technical advances have increased its sensitivity and also extended its potential applications.This review focuses on some basic knowledge of ASL perfusion,emerging techniques and clinical applications in neuroimaging.

全脑3D-ASL和SWI联合检查在急性大面积脑梗死治疗中的价值

目的 探讨3D-ASL和SWI技术对急性大面积脑梗死治疗方案的指导价值。方法 回顾性分析46例急性大面积脑梗死患者在治疗前后的ASL和SWI表现,其中4例于治疗前、4例于动脉溶栓治疗后、5例静脉溶栓治疗后、33例抗凝治疗后、12例于治疗后30~60天复查,根据治疗方案的不同,分别统计急性大面积脑梗死患者ASL像高/低灌注、SWI像出血或侧枝循环形成的影像学表现,按NIHSS评分评价临床愈后效果。结果 本组46例中,14例患者ASL像上呈局部或大部分高灌注,占30%,其余32例为低灌注,占70%;4例行动脉溶栓,ASL像上呈局部或大部分高灌注,SWI像上均可见面积大小不等的低信号出血灶;5例行静脉溶栓,ASL像上呈高灌注3例、呈低灌注2例,SWI像可见脑出血1例;33例行抗凝治疗,7例于治疗后ASL像上呈高灌注,其中5例SWI像可见低信号出血灶,2例SWI像上未见出血灶;26例ASL像呈低灌注,10例SWI像上可见出血灶,16例SWI像未见出血灶。4例有房颤病史且平常口服抗凝药物的患者在抗凝治疗后均于ASL像上表现为高灌注。本组16例中,24例于SWI像上显示梗死区或周围血管增多、增粗,占52%。SWI像上9例可见沿大脑中动脉走行的条状低信号影,占20%。NIHSS评分：1例死亡,5例无变化,其余40例经治疗后均有不同程度好转。结论 联合运用3D-ASL和SWI技术指导急性大面积脑梗死患者的治疗,具有重要的临床价值。

前循环急性缺血性脑卒中脑灌注水平与认知障碍的相关性研究

目的分析首发前循环急性缺血性脑卒中后认知障碍患者脑灌注水平的变化及与认知障碍的关系。方法选取2018年3月至2020年3月于华北理工大学附属开滦总医院神经内科治疗并符合纳入、排除标准的70例首发前循环急性缺血性脑卒中患者进行回顾性分析。采用简易精神状态检查量表(mini-mental state examination,MMSE)分为卒中后认知障碍(post-stroke cognitive impairment,PSCI)组36例,卒中后无认知障碍组34例。全部入选患者行电子计算机断层扫描(computed tomography,CT)和磁共振弥散加权成像(diffusion-weighted MR imaging,MRI-DWI)确立诊断和明确病灶分布;应用磁共振血管造影(magnetic resonance angiography,MRA)检测脑供血动脉狭窄情况;应用三维准连续动脉自旋标记(3D pseudo-continuous arterial spin labeling,3D-pCASL)灌注成像技术,设置两个标记后延迟时间(post label delay,PLD)1.5、2.5 s检测脑血流量。结果(1)两组间临床基本资料比较差异均无统计学意义(P均>0.05)。(2)卒中后认知障碍组病灶侧存在大脑中动脉(middle cerebral artery,MCA)、大脑前动脉(anterior cerebral artery,ACA)、颈内动脉(internal carotid artery,ICA)≥1条或≥2条中重度狭窄/闭塞患者比例[91.67%(33/36)、33.33%(12/36)]高于卒中后无认知障碍组[23.53%(8/34)、8.82%(3/34)];卒中后认知障碍组病灶侧分别存在MCA、ICA中、重度狭窄/闭塞患者比例[69.44%(25/36)、44.44%(16/36)]高于卒中后无认知障碍组[14.71%(5/34)、11.76%(4/34)];差异均有统计学意义(χ^(2)值分别为33.455、6.239、21.394、9.150,P均<0.05)。⑶卒中后认知障碍组同时存在≥2个脑区梗死病灶患者比例[61.1%(22/36)]及额叶梗死病灶构成比[38.03%(27/71)]高于卒中后无认知障碍组[20.6%(7/34)与19.05%(8/42)],差异均有统计学意义(χ^(2)值分别为11.833、4.447,P均<0.05);PLD 2.5 s时,卒中后认知障碍组额叶梗死病灶CBF值[(31.516±8.333)mL/(100 g·min)]低于卒中后无认知障碍组[(45.442±8.281)mL/(100 g·min)],差异有统计学意义(t=3.835,P<0.05);相关性分析发现,PLD 2.5 s额叶梗死病灶CBF值与MMSE评分呈正相关(r=0.738,P<0.05)。⑷卒中后认知障碍组PLD 1.5、2.5 s病灶侧存在≥1个或≥2个低灌注脑区(额叶、颞叶、顶叶)患者比例[88.89%(32/36)、88.89%(32/36)、77.78%(28/36)、66.67%(24/36)]高于卒中后无认知障碍组[67.65%(23/34)、8.82%(3/34)、29.41%(10/34)、0],差异有统计学意义(χ^(2)值分别为4.686、44.837、16.483、34.493,P均<0.05);PLD 1.5 s时,卒中后认知障碍组病灶侧低灌注脑区额叶、顶叶CBF值[(20.260±5.266)mL/(100 g·min)、(17.664±3.947)mL/(100 g·min)]低于卒中后无认知障碍组[(33.442±10.563)mL/(100 g·min)、(28.071±6.913)mL/(100 g·min)],差异有统计学意义(t=3.392、6.225,P均<0.05);PLD 2.5 s时,卒中后认知障碍组病灶侧额叶、顶叶、颞叶低灌注代偿后CBF值[(37.732±8.355)mL/(100 g·min)、(32.942±6.459)mL/(100 g·min)、(39.282±7.443)mL/(100 g·min)]低于卒中后无认知障碍组[(57.189±9.965)mL/(100 g·min)、(52.415±7.017)mL/(100 g·min)、(49.258±8.912)mL/(100 g·min)],差异均有统计学意义(t值分别为5.443、10.227、2.950,P均<0.05);相关性分析发现,PLD 1.5 s病灶侧低灌注脑区额叶、顶叶CBF值及PLD 2.5 s低灌注脑区额叶、顶叶、颞叶低灌注代偿后的CBF值均与MMSE评分呈正相关(r值分别为0.693、0.675、0.823、0.799、0.545,P均<0.05)。结论首发前循环急性缺血性脑卒中后认知障碍患者常合并病灶周围脑区广泛低灌注;首发前循环急性缺血性脑卒中后认知障碍的发生与梗死病灶及病灶周围脑区灌注水平降低有关。