零回波时间动脉自旋标记MR血管成像评估颅内动脉瘤

目的 观察零回波时间(ZTE)动脉自旋标记(ASL)MR血管成像(MRA)评估颅内动脉瘤(IA)的价值。方法 对18例临床疑诊IA患者行头颈部时间飞跃法(TOF)MRA(TOF-MRA)及ZTE ASL-MRA,并于之后2天内行头颈部数字减影血管造影(DSA);评价2种MRA图像显示IA质量(优、良、中等或差)及IA定量参数(瘤高、瘤宽及瘤颈),比较其图像质量评分差异;以DSA结果为金标准,采用组内相关系数(ICC)观察3种检查所获IA定量参数的一致性。结果 18例共21个IA纳入研究。ZTE ASL-MRA显示IA图像质量评分[4(4,4)]高于TOF-MRA[4(3,4),Z=－2.40,P=0.02]。ZTE ASL-MRA(ICC=0.99、0.98、0.99)及TOF-MRA(ICC=0.96、0.96、0.93)所示IA瘤高、瘤宽及瘤颈与DSA结果的一致性均强(P均<0.05)。结论 ZTE ASL-MRA可用于无创、定量评估IA。     

ASL脑灌注成像的应用

ASL(arterial spin labeling)即动脉自旋标记技术，是一种以可自由弥散的水为内在示踪剂的MR灌注成像方法，它利用反转脉冲标记上游动脉血中的水质子，将下游成像层所获标记图像与没有标记的对照组减影而获得器官的血流量。十多年来，ASL已经在人类和动物身上的多种病理、生理情况下证明了其价值。本文综述其近年来的主要应用情况。     

基于动脉自旋标记技术的麻痹性痴呆患者脑血流量特点及其与认知障碍相关性

目的探讨麻痹性痴呆（GPI）患者脑血流量（CBF）特点及其与认知障碍的相关性。 方法纳入2018年1月至2019年12月于首都医科大学附属北京地坛医院就诊的GPI患者18例和健康体检者18例（健康对照组）,采用蒙特利尔认知评估量表评定认知功能。采用磁共振动脉自旋标记技术扫描评估其各个脑区CBF,并进一步应用Spearman相关分析CBF异常区域与认知功能的相关性。 结果GPI患者蒙特利尔认知评估量表评分低于健康对照组[（16.00 ± 7.19）vs. （27.90 ± 1.21）：t =－7.853、P < 0.001）]。18例GPI患者中,头颅MRI正常5例,脑白质病变1例,脑萎缩9例,3例患者同时存在脑萎缩和脑白质病变。健康对照组头颅MRI均未见异常。GPI患者脑13、14、28、37、38、41、42、43、44、46、48、49、50、51、52、69、70、77、78、83、84、88、109、117、165、166、167、168、169、177、178、179、187、188、211、212、213、214、215、216、219、223、227、237和238区CBF显著高于健康对照组（P均< 0.001）。GPI患者认知障碍中的注意力障碍与脑69、70、77、78、166和168区CBF异常有一定的负相关性（r =－0.476、P = 0.046,r =－0.487、P = 0.034,r =－0.604、P = 0.008,r = －0.545、P = 0.019,r =－0.544、P = 0.02,r =－0.522、P = 0.026）。 结论GPI患者存在全脑血流量升高。GPI患者认知功能障碍中的注意力障碍可能与局部脑区血流量升高有一定相关性。局部CBF越高,注意力障碍越严重。这可能也是GPI发病机制之一。     

CTP与HR-MRI对颈动脉狭窄患者行颈动脉支架置入术疗效的评估及应用价值

背景与目的 颈动脉狭窄是导致脑卒中尤其是缺血性脑卒中的重要原因,早期发现及有效治疗是减少缺血性脑卒中发生的关键。颈动脉支架置入术（CAS）是治疗颈动脉狭窄的常用方法,但术中和术后可能发生各种并发症,以及发生再次狭窄或闭塞的风险,因此,通过有效的方法对其进行疗效评估具有重要的临床意义。本研究分析CT灌注成像（CTP）与高分辨磁共振成像（HR-MRI）对颈动脉狭窄患者CAS术后疗效的评估效能。方法 收集2017年2月—2020年2月期间44例颈动脉狭窄并接受CAS治疗的患者资料,所有入选患者于手术前、手术后2个月行CTP、HR-MRI以及DSA检查,比较患者手术前后CTP与HR-MRI参数的差异,以DSA检查结果作为金标准,比较两种方法诊断颈动脉残余狭窄的效能。结果 CTP结果显示,与术前比较,患者术后2个月大脑动脉相对脑血流量明显增多,相对通过时间、相对达峰时间明显减少（均P<0.05）,相对脑血容量无明显差异（P>0.05）;HR-MRI结果显示,与术前比较,患者术后2个月血管面积、管壁面积以及管腔面积无明显差异（均P>0.05）,斑块面积、斑块负荷明显减小（均P<0.05）。DSA检查出16支颈动脉存在狭窄,颈动脉狭窄改善率为80.00%,CTP检查出颈动脉存在狭窄12支,颈动脉狭窄改善率为85.00%,HR-MRI检查出颈动脉存在狭窄14支,颈动脉狭窄改善率为82.50%,两种检查方式对颈动脉残余狭窄的诊断效能相当（P>0.05）。结论 CTP、HR-MRI均可用于颈动脉狭窄患者CAS疗效评估,两种方法补充使用,具有一定的临床应用价值。     

颈动脉支架成形术前应用非增强多对比高分辨磁共振斑块成像评估价值研究

目的 分析非增强多对比高分辨磁共振成像技术在颈动脉支架成形术（CAS）术前评估中的应用价值。方法 回顾性分析2017年1 月至2018 年3月在复旦大学附属中山医院接受颈动脉狭窄接受治疗的181例病人资料,通过单因素和多因素Logistic回归分析明确颈动脉斑块性质与CAS术后脑梗死病灶的关系。结果 共纳入接受CAS手术病人181例,其中术后63例（34.8%）出现无症状性新发弥散加权成像（DWI）病灶,2例（1.1%）出现有症状性脑梗死。病人Logistic回归分析结果显示颈动脉斑块内出血是预测CAS术后的无症状DWI病灶的独立危险因素（IPH）（亚急性期IPH vs. 无IPH：OR=9.393;95%CI 4.431~19.911）。结论 术前应用非增强多对比高分辨磁共振成像对斑块成分进行评估可以发现斑块不稳定成分,对CAS手术病例的选择有重要的潜在价值。     

颈内动脉狭窄处扭曲的血管内治疗

目的 探讨血管内支架成形术治疗颈内动脉狭窄处扭曲的必要性、可行性和安全性.方法 选择2003年12月至2009年12月经数字减影血管造影(DSA)检查证实的症状性颈内动脉狭窄且狭窄处伴扭曲的12例患者,采用血管内支架成形术处理颈动脉狭窄伴扭曲,分析其临床、影像学、支架成形术和随访观察资料,评价治疗效果.结果 12例颈内动脉狭窄伴扭曲的患者全部成功实施血管内支架成形术,支架置入成功率100%,无支架相关死亡或致残.12例患者共置入自膨式支架14枚,平均狭窄率由术前的85.6%下降至11.2%;扭曲角度(Metz观测分类法)由术前＜90°变为＞120°;无围手术期短暂性脑缺血发作(TIA)和脑卒中发生,临床症状改善或消失.临床随访6～72个月,发生支架同侧和对侧TIA各1例;5例患者行DSA检查,其中1例发生再狭窄并在支架远端发生新的扭曲,再次支架置入治疗,2年后CT血管造影(CTA)复查未见扭曲和支架内再狭窄;另外7例行颈部血管超声检查,未见再狭窄和扭曲.结论 血管内支架成形术治疗颈内动脉狭窄伴扭曲,技术上是可行、安全的,可能有助于减少脑缺血发生,但有待于进一步观察.

Abstract：

Objective To study the necessity, feasibility, security of carotid angioplasty and stenting (CAS) for symptomatic carotid stenosis combined with kinking. Methods Twelve patients with symptomatic carotid stenosis and kinking demonstrated by digital subtraction angiography (DSA) received CAS from December 2003 to December 2009. There were 9 male and 3 female patients, age ranged from 59 to 77 years(mean 69.3 years). All the patients' clinical, imaging, intervention and follow up data were collected and analyzed. Results All CAS procedures were successfully performed with 14 self-expandable stents placed. The mean degree of stenosis was reduced from 85. 6% before stenting to 11.2% after stenting,the angle of kinking, according to Metz' category, were improved from less than 90° to more than 120° in each case. No perioperative procedure related stroke and tranient ichemic attack (TIA) occurred. The clinical symptoms and signs of cerebral ischemia were improved or disappeared for all patients. During follow-up of these 12 patients for 6 to 72 months, one patient experienced ipsilateral carotid territory TIA and another patient experienced contralateral carotid territory TIA. DSA follow up of 5 patients demonstrated 1 case with in-stent restenosis and arterial kinking remote to the stent of internal carotid artery. CAS were performed again and CT angiography follow up demonstrated no kinking and restenosis 2 years after the intervention. Duplex scan of the other 7 patients demonstrated neither kinking nor restenosis. Conclusions CAS seems to be feasible and safe for the patients with symptomatic kinking and stenosis, and maybe helpful to lower the risk of cerebral ischemia, but further study is needed.     

支架置入治疗颈内动脉狭窄病人的护理

对6例颈内动脉狭窄病人行支架置入治疗．结果均一次置入成功．术后病人症状明显改善．未发生不良反应。提出术前周密的准备．术中、术后严密监测血压、精神神经症状及肢体活动情况,发现异常及时处理是保证治疗成功的重要因素。     

影像学检查在颈动脉狭窄评估中的应用探讨

颈动脉狭窄而致的管腔阻塞、斑块拥堵等情况是引发脑卒中和一过性脑缺血发作等严重临床症状及综合征的重要原因.临床上,运用超声、数字减影血管造影、计算机断层扫描(CT)及磁共振成像等影像学检查手段对颈动脉狭窄程度和管壁损伤进行探查,直观简洁,方便操作.对于疾病进行早期评估与治疗,可以极大程度地降低严重并发症的发生率,改善患者...     

应用自旋标记—顺磁共振研究严重烧伤大鼠早期心肌细胞膜变化

目的利用自旋标记—顺磁共振技术研究严重烧伤大鼠早期心肌细胞膜的变化。方法用5-氮氧自由基硬脂酸(5-doxylstearic acid,5NS)和16-氮氧自由基硬酯酸((16-doxylstearic acid,16NS)分别掺入到不同深度的膜类脂区,观察严重烧伤对大鼠心肌细胞不同深度的膜类脂区流动性的影响,同时用3-甲基马来酰亚胺氮氧自由基(3-maleidoproxy1,3MP)标记膜蛋白巯基,观察膜蛋白旋转相关时间(τ_c)及强固定化与弱固定化组分谱线高度比值(h_s/h_w)的变化。结果严重烧伤大鼠早期心肌细胞膜脂浅层的序参数(S)值无明显变化,而膜脂深层 S 值增大,膜蛋白 h_s/h_w 显著增大,膜蛋白旋转相关时间τ。也显著增大。结论严重烧伤后早期即出现心肌细胞膜的损伤,表现为膜脂质深层流动性下降,膜蛋白构象改变,膜蛋白运动受限。这些变化可以直接影响细胞膜蛋白的功能,从而导致心肌细胞功能的变化。     

应用自旋标记——顺磁共振研究严重烧伤大鼠早期心肌细 …

目的 利用自旋标记－顺磁共振技术研究严重烧伤大鼠早期心肌细胞膜的变化。方法 用５－氮氧自由基硬脂酸和１６－氮氧自由基硬酯酸分别主到不同深度的膜类脂区,观察严重烧伤地大鼠心肌细胞不同深度的类脂区流动性的影响,同时用３－甲基马来酰亚胺氮氧自由基标记膜蛋白巯基,观察膜蛋白旋转相关时间及强固定化与弱固定化组分谱线高度比值的变化。结果 严重烧伤大鼠早期心肌细胞脂浅层的序参数（Ｓ）值无明显变化,而膜脂深层Ｓ值     

Unilateral carotid stenosis and impaired cerebral hemispheric vascular reserve

Single photon emission computed tomography (SPECT) scanning with 99TcHMPAO (Ceretec) was used to demonstrate regional cerebral blood flow (rCBF) in sixteen patients with hemodynamically significant unilateral carotid stenosis. All patients were demonstrated by cerebral computed tomography to be without cerebral infarction. When dysautoregulation was induced by intravenous acetazolamide, eight patients demonstrated a perfusion defect ipsilateral to carotid stenosis. Repeat SPECT scanning with dysautoregulation following carotid endarterectomy showed improved or normal cerebral perfusion in seven of these patients. The results suggest that a hemodynamic mechanism for cerebral ischemic events, including transient ischemic attacks (TIA) may be more common than previously suspected. Carotid disobliteration usually improves ipsilateral cerebrovascular reserve in patients with a preoperative perfusion defect.     

Regional cerebral blood flow in patients with vertebrobasilar disease

We have investigated the changes in regional cerebral blood flow (rCBF) in patients with occlusive vertebrobasilar disease. Fifty patients who showed severe stenosis or occlusion of the vertebrobasilar artery territory were studied by angiography. Lesions in 13 of these patients were limited to the vertebrobasilar artery (limited VB group), and 37 patients showed combined vertebrobasilar/carotid artery lesions (combined VB-C group). Measurements of rCBF in the group of 50 patients using the intravenous xenon 133 technique showed that there was a significant decrease in the mean rCBF (47.5 ± 1.4 ml/100 gm/min) as compared with 19 age-matched normal subjects (54.9 ± 1.8 ml/100 gm/min). There was also a significant difference in mean rCBF between the combined VB-C group (45.6 ± 1.5 ml/100 gm/min) and a group of 153 patients with limited carotid artery lesions (C group, 49.8 ± 1.0 ml/100 gm/min). However, no significant difference in mean rCBF was found between the limited VB group and normal subjects. There were no differences in rCBF when evaluated according to the presence or absence of angiographic collateral circulation via the posterior communicating artery (Pcom). Good correlation was found between mean rCBF and direction of collateral flow via the Pcom (p < 0.05). The value of hemispheric rCBF of patients with carotid system transient ischemic attacks (TIAs) was significantly lower than that of patients with vertebrobasilar system TIAs (p < 0.02). In cerebral autoregulation tests of 24 patients with occlusive vertebrobasilar disease (7 patients from the limited VB group and 17 patients from the combined VB-C group), 13 of these 24 patients (54%) showed an impairment of autoregulation.     

False-negative magnetic resonance angiography with extracranial internal carotid artery stenosis

Magnetic resonance angiography (MRA) is increasingly used as a noninvasive means to assess internal carotid artery (ICA) stenosis. When used alone, however, MRA may not be sufficiently accurate in certain settings to determine whether ICA disease meets surgical criteria. Although MRA has been recognized to overestimate the degree of stenosis, the authors present two cases in which it severely underestimated arterial stenosis. Two male patients, 70 and 40 years old, respectively, were admitted with crescendo transient ischemic attacks. Their MRA studies suggested nonsurgical lesions of the ICA. After the patients continued to demonstrate clinical evidence of embolic disease, digital subtraction angiography (DSA) was performed on one patient, and the other received a gadolinium contrast-enhanced MRA. These tests revealed critical stenosis in each patient. Each was taken to the operating room for awake carotid endarterectomy with heparin anticoagulation and electroencephalographic monitoring. At surgery, both patients were found to have severely stenosed ICAs with complex plaques. MRA to determine whether ICA stenosis meets surgical criteria may not be sufficiently accurate in certain clinical settings. Additional imaging studies, such as confirmatory digital ultrasonography, MRA with gadolinium contrast, or DSA, may be required to determine the extent of carotid artery stenosis accurately.     

颈动脉支架术中脑保护措施的应用

颈动脉狭窄是造成脑卒中的主要原凼.颈动脉支架置人术治疗颈动脉狄窄对患者创伤小、痛苦少,已逐渐成为治疗颈动脉狭窄的首选术式.而术中脑保护装置的应用更大大提高了其疗效.本文对颈动脉成形术中应用脑保护的有关问题进行概述.相信随着许多大规模、多中心临床实验的完成,脑保护下的颈动脉支架置入术将在颈动脉狭窄患者的卒中预防和治疗中发挥重要作用.     

Experience in colour‐flow duplex carotid imaging for extracranial carotid stenosis

Carotid duplex scanning is a non‐invasive, cost‐effective method for the diagnosis of stability, progression or improvement of extracranial cerebral disease. It yields functional information that complements the anatomic information provided by angiography. It can localize the disease with B‐mode ultrasound and can determine the functional severity of the disease with spectral analysis and colour‐flow imaging. The diagnostic criteria are based on the peak systolic velocity and end diastolic velocity of the internal carotid artery. Carotid stenosis of 70% or greater is taken as significant. The texture and morphology of the plaque can be reported as either homogeneous, heterogeneous with ulceration or heterogeneous without ulceration. This distinction would not be detected readily by angiography. With a high degree of accuracy in identifying sig‐nificant stenoses in carotid arteries, duplex scanning can replace angiography prior to performing carotid endarterectomy.      

The natural history of amaurosis fugax with minor degrees of internal carotid artery stenosis

The natural history of amaurosis fugax with hemodynamically insignificant degrees of internal carotid artery stenosis is uncertain. Seventy-three patients over age 40 who presented with amaurosis fugax without obvious cause and had ipsilateral stenoses of 50% or less with carotid duplex scanning were followed for a mean period of 35.5 months (range 3–110) without surgical intervention. At the initial vascular laboratory duplex evaluation, 35 patients had normal arteries (47.9%), 29 had minor (0–19%) stenoses of the ipsilateral internal carotid arteries (39.7%), and 11 had 20–50% stenosis (15.1%). Four patients with 0–19% stenosis and one patient with 20–50% stenosis experienced a subsequent stroke or permanent ipsilateral blindness. When analyzed by life-table format, stroke, blindness, and early death were more frequent in patients with minor degrees of stenosis than in those with normal arteries. Investigations in all patients with amaurosis fugax should be aimed at identifying whether the symptoms are explained by arteriosclerotic, systemic, collagen, cardiac, hematologic, or ophthalmologic disease. When no other etiology is found, and localized carotid bifurcation atherosclerosis of even modest degrees is identified, an atheroembolic etiology should be considered.     

Internal carotid artery volume flow correlates to rCBF measurements

Summary ¶Background. There is no simple, cost effective bedside method available for measuring global cerebral blood flow (CBF) rapidly and repeatedly. Method. Based on the ultrasound technique a device was developed to measure flow volume per unit of time in the internal carotid artery. The system utilizes dual beam, angle-independent Doppler technology, and employs simultaneous sampling and full spectrum determination. The aim of this study was to evaluate this device in comparison with cerebral blood flow measurements using the well established Xenon¹³³ clearence technique. Findings. 10 patients suffering from SAH were included. 20 measurements were performed. CBF was measured employing the Xenon¹³³ clearence technique. Velocity profiles across the ICA were obtained with the high-resolution FlowGuard Doppler ultrasound flow system (Cardiosonix Ltd., Israel). According to the statistical analysis the ICA flow correlated significantly to the mean rCBF15 index of the hemisphere (p<0.0001). Conclusions. This new device seems to be promising for monitoring cerebral blood flow in critically ill neurological and neurosurgical patients.Published online September 18, 2003     

Magnetic resonance imaging assessment of renal flow distribution patterns during ex vivo normothermic machine perfusion in porcine and human kidneys

Acceptance criteria of deceased donor organs have gradually been extended toward suboptimal quality, posing an urgent need for more objective pre-transplant organ assessment. Ex vivo normothermic machine perfusion (NMP) combined with magnetic resonance imaging (MRI) could assist clinicians in deciding whether a donor kidney is suitable for transplantation. Aim of this study was to characterize the regional distribution of perfusate flow during NMP, to better understand how ex vivo kidney assessment protocols should eventually be designed. Nine porcine and 4 human discarded kidneys underwent 3 h of NMP in an MRI-compatible perfusion setup. Arterial spin labeling scans were performed every 15 min, resulting in perfusion-weighted images that visualize intrarenal flow distribution. At the start of NMP, all kidneys were mainly centrally perfused and it took time for the outer cortex to reach its physiological dominant perfusion state. Calculated corticomedullary ratios based on the perfusion maps reached a physiological range comparable to in vivo observations, but only after 1 to 2 h after the start of NMP. Before that, the functionally important renal cortex appeared severely underperfused. Our findings suggest that early functional NMP quality assessment markers may not reflect actual physiology and should therefore be interpreted with caution.