TCD, MRA and MRI in acute cerebral ischemia

Objectives - The aim of this study was to determine accuracy of transcranial Doppler ultrasound (TCD) and compare efficacy of three non-invasive tests [TCD, magnetic resonance angiography (MRA), and magnetic resonance imaging (MRI)] in patients with acute cerebral ischemia. Material and methods - This prospective study involved 30 patients. MRI, MRA, and TCD were performed within 24 h after onset of ictus. The 2nd MRI was repeated at 48–72 h and was used as the standard for the evaluation of sensitivity and specificity of MRA, TCD, and initial MRI. Results - TCD showed a sensitivity of 96% and a specificity of 33% for recognizing abnormal cerebral blood flow velocities. MRA showed a sensitivity of 46% and a specificity of 75% for assessing intracranial vascular anatomy, while initial MRI revealed a sensitivity of 84% and a specificity of 100% for evaluation of ischemic parenchymal changes. Conclusion - Our results revealed that TCD is an accurate indicator of blood flow status and correlated well with MRI, MRA abnormalities in acute stroke.     

无症状脑梗塞MRI、MRA及TCD的临床对比研究

目的 探讨无症状脑梗塞(SCI)的临床特征与头颅MRI、MRA、TCD改变。方法 对50例病人进行临床分析，并进行头颅MRI、MRA和TCD检测，加以对比分析。结果 MRI检出梗塞灶的病人行MRA检查，异常检出率为93.02％，TCD异常检出率为94.87％。结论 MRI是确诊SCI重要条件之一，并能清晰、准确显示小脑、脑干梗塞；MRA能显示病变血管；TCD对SCI有早期辅助诊断价值，对治诊及预后有很好指导作用。     

Post-partum cerebral angiopathy. A rare cerebrovascular complication

We describe two patients with post-partum cerebral angiopathy. (Case 1) A 24-year-old patient developed vaginal bleeding 1 day post-partum. She received blood transfusion and ergometrine. Four days later she experienced severe occipital headache, loss of vision and generalized seizures. An MRI showed right occipital lesion. She was treated with phenytoin and prednisone. Her vision returned to normal within 2 days. Cerebral angiography showed multiple segmental narrowing; 6 h later severe occipital headache and cortical blindness recurred. She was treated with nimodipine and prednisone with complete recovery in 10 days. (Case 2) On the 7th post-partum day a 24-year-old patient was given ergometrine. One day later she developed severe headache and hypertension, followed by drowsiness, right hemiplegia and aphasia. A left frontal hematoma was seen on the CT scan. Cerebral angiography showed multiple segemental narrowing. Resolution of this angiography was confirmed on follow-up angiography. Post-partum cerebral angiopathy is a rare complication of a normal pregnancy. It may present as an ischemic or hemorrhagic stroke. The transience of this severe complication and its association with the administration of drugs with strong vasoconstrictive properties suggest and etiological relationship. Other factors and the exact mechanism are unclear.     

MRA、MRI、TCD对椎—基动脉改变对比研究

观察经颅多普勒(TCD)对椎基动脉病变诊断的可靠性。方法:Ⅰ组13例应用MRI确诊之脑干梗塞病人。Ⅱ组42例有临床改变;如眩晕,走路不稳,眼颤等,TCD检查有异常改变者,则同时进行MRI和MRA检查。两组患者皆无意识障碍。结果:Ⅰ组13例MRI皆有脑干,小脑异常改变(其中4例为幕上基底节梗塞),TCD有V—BAvm下降或上升,仅一例RPICA消失。TCD异常率100%。Ⅱ组:42例MRA异常者30例,正常者12例,而MRI仅4例正常,异常者38例(其中17例基底节梗塞)而TCD为100%异常。结论:MRI异常者占92.72%,正常者4例,而MRA由于检查时间其异常者为71.43%12例正常,但TCD检查为100%异常。所以MRI,MRA,TCD相辅配合,可起到相辅相成的作用。     

TIA继发脑梗死的TCD、EEG与CT、MRI的动态研究初探

目的探讨TIA继发脑梗死的TCD动态变化规律以及与病情预后、神经电生理、神经影像之间的关系。方法对TIA继发脑梗死患者在入院即刻、脑梗死后第1、3、7、14天进行床边TCD动态观察,并与EEG、头颅CT、MRI和NIHSS评分进行对比研究及相关分析。结果入院即刻TCD异常率高于头颅CT、MRI和EEG,并且异常程度与NIHSS评分成正比关系,能更早预测患者病情及预后。结论对TIA继发脑梗死的患者,TCD具有较高的早期诊断价值,入院即刻TCD的异常程度与脑梗死后病情严重程度及早期预后有关,有助于判断病情及预后。     

DWI及MRA在大面积脑梗塞早期诊断中的价值

目的:评价弥散加权磁共振成像DWI和磁共振血管成像MRA对早期大面积脑梗塞的诊断价值。方法:对24例早期大面积脑梗塞的临床和磁共振资料进行分析,全部患者均行DWI及MRA检查。结果:24例早期大面积脑梗塞中,13例急性期CT扫描未检测出确切病灶,DWI扫描全部出现大片异常高信号,病灶检出率为100％。而在常规T2WI检查中,7例为阴性,病灶检出率为69％。MRA发现血管异常24例,表现为供血动脉闭塞,狭窄、硬化。结论: DWI有助于明确早期大面积脑梗塞病变范围,且能区别新旧病灶。MRA能直接显示大面积脑梗塞闭塞的供血脑血管,联合使用DWI和MRA对早期大面积脑梗塞诊断有重要的临床价值,也有利于早期合理的治疗方案制定及预后判断。     

TCD与DSA,MRA,CTA蛛网膜下腔出血中应用对比研究

应用经颅多普勒超声（ＴＣＤ）、数字减影血管造影（ＤＳＡ）、磁共振血管成像（ＭＲＡ）、ＣＴ血管造影（ＣＴＡ）对２４例蛛网膜下腔出血（ＳＡＨ）病人进行了对照研究。通过ＴＣＤ诊断血管痉挛和狭窄性病变１９例（７９％），治疗前后动态观察发现脑底动脉平均流速（Ｖｍ）增高。诊断颅内压增高２例（８．３％）Ｖｍ降低。血管造影等放射影像学检查，发现动脉瘤８例，动脉炎样改变６例，动脉痉挛２例，正常者８例，总异常率为６６．６％。通过超声与放射影像学比较发现，两者可以从不同角度显示脑血管的功能或病理状态。     

130例慢性脑供血不足患者脑电图及经颅多普勒检测结果分析

目的探讨脑电图(EEG)和经颅多普勒(TCD)在慢性脑供血不足诊断中的应用价值。方法对130例临床诊断为CCC I的患者同时进行EEG和TCD检测和对比分析,并与正常标准组进行对比。按年龄段分别计算TCD,EEG阳性率以及共同阳性率。再将患者分为头痛头晕两组再次比较,同时观察TCD及EEG的变化特点。将患者按平均血流速度(Vm)值的高低分为高流速组,低流速组,正常流速组分别同正常组作比较。结果TCD主要表现为多支血管全程血流速度加快或减慢及单支血流速度节段性加快或减慢,两侧流速不对称,PI,R I,S/D的增高,频谱异常S2大于S1,或S2与S1相融合。EEG的异常表现为波幅减低,α活动减少或泛化的慢α波,调幅调节差。散在的或弥漫的θ波,同时可混有少量的δ波。未见特异性脑电波改变。TCD的总阳性率为88.24%,EEG的总阳性率为75.49%,两者联合检测的阳性率92.16%。TCD年龄分组颞窗的未探及率分别为12%,45%,66%。TCD检测Vm高流速组及低流速组与对照组比较P<0.01。正常流速组与对照组比较P>0.05。Vm症状分组头晕组与头痛组的高流速,低流速分组同对照组比较均P<0.01。头晕组同头痛组比较P>0.05。脑电图检测中边缘状态脑电图72例,占异常脑电图的93.51%。轻度异常脑电图4例,占异常脑电图的5.19%。中度异常1人占异常脑电图的1.3%。结论中年慢性脑供血不足患者TCD的检测更有价值,老年患者,随着颞窗未探及率的增加EEG的检测阳性率高于TCD,但两者联合检测可显著提高早期诊断率,对临床综合治疗及评价预后有着重要的价值。     

磁共振血管成像、经颅多普勒及颈动脉超声对颈动脉系统短暂性脑缺血发作的诊断价值

目的 探讨磁共振血管成像（MRA）、经颅多普勒（TCD）和颈动脉超声对颈动脉系统短暂性脑缺血发作（TIA）的诊断价值。方法 对42例颈动脉系统TIA患者进行MRA、TCD和颈动脉超声检测,观察其异常情况。结果 颈动脉MRA异常12例（28．6％）,脑MRA异常32例（76．2％）,其中8例二者均异常,大多为颈动脉轻～重度狭窄;TCD异常30例（71．4％）（此30例脑MRA均异常）;颈动脉超声异常16例（38．1％）（其中颈动脉MRA异常12例）。结论 MRA、TCD和颈动脉超声3种方法联合应用,可对颈动脉系统TIA的病因及诊断作出客观的评价。     

缺血性脑血管病颅内脑动脉狭窄的TCD、MRA对比检测

目的评价TCD、MRA诊断缺血性脑血管病患者颅内脑动脉狭窄的临床应用价值。方法203例颞窗良好的缺血性脑血管病患者行经颅多普勒(TCD)检测发现颅内脑动脉狭窄,全部病例3d内再行磁共振血管造影(MRA)检查,5例行数字减影血管造影(DSA)。结果TCD检测发现狭窄大脑中动脉236支,MRA检查发现狭窄大脑中动脉225支．TCD与MRA诊断相符大脑中动脉数为219支。结论TCD和MRA是诊断颅内脑动脉狭窄准确性较好的无创性检查方法,两者联合应用评价颅内脑动脉狭窄精确性更高。     

Review: sporadic cerebral amyloid angiopathy

Cerebral amyloid angiopathy (CAA) may result from focal to widespread amyloid-β protein (Aβ) deposition within leptomeningeal and intracortical cerebral blood vessels. In addition, pericapillary Aβ refers to Aβ depositions in the glia limitans and adjacent neuropil, whereas in capillary CAA Aβ depositions are present in the capillary wall. CAA may cause lobar intracerebral haemorrhages and microbleeds. Hypoperfusion and reduced vascular autoregulation due to CAA might cause infarcts and white matter lesions. CAA thus causes vascular lesions that potentially lead to (vascular) dementia and may further contribute to dementia by impeding the clearance of solutes out of the brain and transport of nutrients across the blood brain barrier. Severe CAA is an independent risk factor for cognitive decline. The clinical diagnosis of CAA is based on the assessment of associated cerebrovascular lesions. In addition, perivascular spaces in the white matter and reduced concentrations of both Aβ(40) and Aβ(42) in cerebrospinal fluid may prove to be suggestive for CAA. Transgenic mouse models that overexpress human Aβ precursor protein show parenchymal Aβ and CAA, thus corroborating the current concept of CAA pathogenesis: neuronal Aβ enters the perivascular drainage pathway and may accumulate in vessel walls due to increased amounts and/or decreased clearance of Aβ, respectively. We suggest that pericapillary Aβ represents early impairment of the perivascular drainage pathway while capillary CAA is associated with decreased transendothelial clearance of Aβ. CAA plays an important role in the multimorbid condition of the ageing brain but its contribution to neurodegeneration remains to be elucidated.     

MRI detection of new hemorrhages: potential marker of progression in cerebral amyloid angiopathy.

The authors used serial gradient-echo MRIs to detect new small hemorrhages in patients with previous lobar hemorrhage. Of 24 lobar hemorrhage patients (17 diagnosed with probable and 7 with possible amyloid angiopathy) who prospectively underwent repeat MRI 1.5 years after initial study, 9 (38%) demonstrated additional hemorrhages at follow-up. Interrater agreement was high. New hemorrhages were more frequent in patients with probable amyloid angiopathy (8 of 17, 47%) with more hemorrhages at baseline (p < 0.01). These results suggest a role for gradient-echo MRI in assessing disease progression in amyloid angiopathy.     

MRI, MRA, and neurodevelopmental outcome following neonatal ECMO

Cranial magnetic resonance imaging (MRI) of 31 newborn infants treated with venoarterial cardiopulmonary bypass for severe but reversible respiratory failure, revealed major focal parenchymal lesions in 7 of 31 infants (23%) and demonstrated abnormal enlargement of extra-axial and ventricular cerebrospinal fluid spaces in 16 of 31 (51%). No preferential left versus right lateralization of focal injury was observed in conjunction with right common carotid artery and jugular vein ligation. No statistically significant relationships were found between major brain lesions on MRI scans and the clinical characteristics of the pre-extracorporeal membrane oxygenation (ECMO), ECMO, and post-ECMO course. Major focal brain lesions were significantly associated with an asymmetric cerebrovascular response to carotid ligation of the right versus left middle cerebral arteries as detected by magnetic resonance angiography (P < .05). Enlarged cerebrospinal fluid spaces were not significantly related to the presence of parenchymal MRI lesions, but were associated with lower Bayley neurodevelopmental scores for mental (MDI) and psychomotor evaluations (PDI) at 6 and 12 months (P < .05). It is concluded that asymmetries of cerebral vascular adaptation detected by magnetic resonance angiography after ECMO may be associated with major brain lesions revealed by MRI. Thereafter, the presence of enlarged cerebrospinal fluid spaces on MRI is associated with a poor shortterm developmental outcome.     

Early cerebral MRI in preterm infants: correlations with EEG and outcome]

AIM OF THE STUDY: Assess the potential benefits of performing an early cerebral MRI to evaluate the gravity of cerebral lesions among premature neonates at risk of neurologic sequels and establish correlations between EEG findings, abnormal neuroimaging findings and neurodevelopment. METHODS: A MRI was performed in 34 premature newborn babies with abnormal neurological clinical signs, and/or with two abnormal EEG and/or with two abnormal cerebral ultrasound scans. The mean age and the adjusted age of our population were 5 weeks (range 1-11 weeks) and 35 weeks of adjusted age (range 29-40 weeks) respectively. The neuroimaging findings were correlated to the results of three EEGs (recorded before 15 days old, between 15 days and one month old, and after the first month of life) and to neurodevelopment. RESULTS: Two statically significant correlations were found between: 1) the severity of brain injuries observed in MRI and the results of the latest EEG (sensitivity 100%, specificity 60%), 2) the severity of brain injuries observed in MRI and abnormal neurodevelopment (sensitivity 75%, specificity 80%). There was no correlation between the abnormal development and the results of EEG recordings. CONCLUSION: Early cerebral MRI is justified in a selected premature population. It is useful for the diagnosis, the evaluation of the severity of brain injury and for the management of these children. The correlation with EEGs traces allows the detection of the majority of prematures babies that will develop sequels.     

Sporadic cerebral amyloid angiopathy: pathology, clinical implications, and possible pathomechanisms

Cerebral amyloid angiopathy (CAA) was observed for the first time nearly 100 years ago and systematically described in 1938. It is a common finding in elderly individuals, defined by -amyloid peptide (A) depositions in cerebral blood vessels, and associated with Alzheimers disease (AD). A variety of genetic mutations cause hereditary forms of CAA; in this review, however, only the sporadic variant of CAA is considered. In CAA, A depositions primarily occur in the abluminal portion of the tunica media, and with increasing severity all layers of the blood vessel wall are infiltrated and an additional spread of A into the surrounding neuropil may be seen (i.e., dyshoric changes). CAA is most pronounced in the occipital lobe and its distribution is usually patchy. The relationship between CAA and AD is poorly understood; however, low positive correlations between the severity of both CAA and AD pathology have been observed. CAA is a frequent cause of (warfarin-associated) intracerebral hemorrhage, and the diagnosis of probable CAA-related hemorrhage can be made during life with high accuracy. Both APOE-4 and APOE-2 are risk factors for CAA, while only APOE-2 increases the risk for hemorrhage in CAA. Although the role of CAA as an independent risk factor for cognitive decline is unclear, severe CAA is likely to lower the threshold for clinically overt dementia in neurodegenerative diseases. As for the origin of A in CAA, it may be both produced by smooth muscle cells (vessel wall) and derived from neurons in the course of perivascular drainage.     

MRA、TCD及椎动脉超声对椎基底动脉系统缺血性卒中的诊断价值

目的 探讨椎动脉磁共振血管成像(MRA)、经颅多普勒(TCD)及椎动脉超声对椎基底动脉系统缺血性卒中的临床诊断价值.方法 对41例椎基底动脉系统缺血性卒中的患者进行椎动脉MRA、TCD及椎动脉超声检测,观察其异常情况.结果 41例患者中椎动脉MRA异常27例(65.85%),TCD异常32例(78.05%),椎动脉超声异常25例(60.98%).椎动脉MRA能清楚地显示血管病理形态,主要表现为椎动脉局部狭窄、单侧椎动脉变细及血流信号降低.结论 椎动脉MRA、TCD与椎动脉超声的联合检查有助于椎基底动脉系统缺血性卒中的病因诊断.