滤器保护的颈动脉支架成形术的微栓子和脑血流监测

目的研究滤器保护的颈动脉支架成形术(CAS)术前、术中和术后微栓子及脑血流变化。方法对5例颈动脉严重狭窄(>70%)患者进行6次CAS,在术前、术中和术后使用M模经颅多普勒超声(TCD)监测大脑中动脉(MCA)的微栓子和脑血流。术后随访,记录新的血管性事件。结果CAS术中监测发现单纯造影时出现大量微栓子信号(MES)。此外,MES数目最多的手术操作步骤是预扩张(n=116)和支架放置(n=135,91,113,90,106,125),后扩张时MES数目相对较少(n=8,14,37,16)。术中MCA收缩期血流速度与平均血流速度比值变化发生在预扩张(46/31至76/54)和后扩张(40/26至74/49,0/0至114/69,35/24至116/71,50/36至137/86)时。术前有2例患者存在MES,术后MES消失。术后与基线相比,MCA血流速度或者搏动指数增加,术中无并发症。1例回收滤器中有脱落组织碎片。随访3～19个月,有1例新发脑梗死,位于CAS对侧。结论TCD监测可以评价滤器保护的CAS术前、术中和术后微栓子发生和脑血流变化。滤器可以过滤较大组织碎片,减少术中栓塞,而并不影响脑血流。可以通过滤器的气泡和小的固体颗粒一般不会导致临床症状的出现。     

Usefulness of transcranial color-coded sonography in the diagnosis of cerebral vasospasm

BACKGROUND AND PURPOSE: The noninvasive diagnosis of cerebral vasospasm with the use of conventional transcranial Doppler ultrasonography (TCD) is based on a velocity study of the middle cerebral artery (MCA). The authors report a prospective comparative study between transcranial color-coded sonography (TCCS), conventional transcranial Doppler (TCD), and angiography in the diagnosis of cerebral vasospasm after surgical treatment for aneurysm. METHODS: Thirty consecutive patients underwent routine angiography after surgical treatment for intracranial aneurysm. The distribution of vasospasm was determined after a prospective calculation of the angiographic diameter of the MCA, internal carotid artery (ICA), and anterior cerebral artery (ACA). The blood flow velocities (systolic and maximum) of the MCA, ICA, and ACA were evaluated by TCCS and TCD. RESULTS: The correlation between mean maximum velocity and angiographic diameter was significant for the MCA (r=-0.637, P<0.0001), ICA (r=-0.676, P<0.0001), and ACA (r=-0.425, P<0.01). TCCS sensitivity and specificity were higher than those for TCD for MCA (100% and 93%, respectively) and ICA (100% and 96.6%, respectively). For ACA, the sensitivity and specificity were 71.4% and 84.8%, respectively. CONCLUSIONS: The authors suggest that TCCS is useful for accurate monitoring of cerebral vasospasm in the MCA and ICA. In the ACA, TCCS monitors the hemodynamic state of the anterior part of the circle of Willis, which could expose the patient to a delayed ischemic deficit.     

短暂性脑缺血发作病人脑循环中微栓子信号与脑卒中的危险性研究

目的 对短暂性脑缺血发作（TIAs)病人观察脑循环微栓子信号（MES）发生率及其发生脑卒中的危险率。方法 用经颅多普勒（TCD）监测TIAs病人双侧大脑中动脉（MCA）微栓子信号（MES）,并跟踪观察12个月。结果 25例短暂脑缺血发作病人有5例记录到MES（阳性率20％）,跟踪观察12个月,5例MES阳性病例中的3例（60％）发生脑梗死;而20例未记录到MES的病人中,仅有2例（10％）发展为脑梗死。结论 可检测到MES的TIAs病人发生梗死的危险性比无MES病人高。     

颈动脉内膜切除术中经颅多普勒超声监测的应用

目的 应用经颅多普勒超声（trascranial Doppler,TCD）术中监测研究颈动脉内膜切除术（carotidendarterectomy,CEA）术中的脑血流变化和微栓子出现的规律。方法 应用TCD监测18例颈内动脉严重狭窄或闭塞者CEA中各期的同侧大脑中动脉（middle cerebralartery,MCA）的脑血流和微栓子信号（microembolic signal,MES）。记录CEA各期MCA收缩期血流速度（peak systolic velocity,PSV）、搏动指数（pulsitility index,PI）及微栓子的数量。结果 （1）术中1例患者出现左眼动脉颞上支栓塞,其余患者无并发症。（2）释放期和缝合期MCA的PSV及PI较基线期明显升高（P <0.01）。44.4%（8/18）的患者阻断后PSV下降>60%。术中,77.8%（14/18）的患者采取了分流措施。释放颈内动脉后33.3%（6/18）的患者PSV升高100%以上。（3）100%的患者于手术中监测到MES。患者的总MES为11～150个,平均60±42个。栓子主要集中于分流期和释放期。结论 TCD作为一项无创、实时的监测工具能够广泛应用于CEA术中监测,及时地发现围手术期的各种血流变化及MES的产生,有效预测围手术期的卒中发生,优化术中操作。     

双焦距经颅多普勒在大脑中动脉狭窄患者检测微栓子的研究

目的 研究大脑中动脉（ＭＣＡ）狭窄患者采用ＴＣＤ检测微栓子（ＭＥＳ）的诊断价值。方法 对２１例年龄在３５￣５７岁的单侧ＭＣＡ狭窄患者,经ＣＴ／ＭＲＩ证实为脑梗死。均进行３０分钟的双焦距ＴＣＤ监测。结果 ４例（１９．０％）检测到ＭＥＳ。其中３在狭窄远端检测到,１例近,远端均检测到。均为大面积脑梗死（４／１３,３０．８％）,而腔隙性梗死未发现ＭＥＳ。结论 双焦距ＴＣＤ检测ＭＥＳ对于确定栓子来源有重要价     

以急性多发性脑梗死为首发表现的隐匿性躯体恶性肿瘤12例报告

目的研究以急性多发脑梗死为首发表现的隐匿性躯体恶性肿瘤患者的临床表现、实验室检查、影像学、微栓子监测检查特点,探讨其可能的发病机制。方法纳入以急性多发性脑梗死为首发表现的隐匿性躯体恶性肿瘤患者12例,收集其临床资料,分析其实验室血液学、头颅MRI、微栓子监测结果及其治疗和预后。结果所有患者均以局灶性神经功能缺损为主要表现,包括偏瘫、失语、偏身感觉障碍、构音障碍、眩晕、肢体抽搐等。头颅DWI示急性多发脑梗死,病灶播散性分布,不符合单支动脉供血区,同时累及双侧前循环或前后循环。11例行D-dimer检查者8例升高。7例行微栓子监测有5例阳性。隐匿性躯体恶性肿瘤包括:肺癌5例,胰腺癌3例,胃癌、结肠癌、子宫内膜癌、转移性低分化粘液腺癌原发肿瘤部位不明各1例;诊断时就已有远处转移者10例。病程中缺血性卒中复发者7例,急性心肌梗死4例,住院期间死亡3例,预后差。结论对于不符合单支动脉供血区的多发急性脑梗死,需要考虑可能合并隐匿性躯体恶性肿瘤,凝血功能筛查高凝状态和微栓子阳性可能是诊断提示线索。     

Acute effects of smoking on human cerebral blood flow: a transcranial Doppler ultrasonography study.

Middle cerebral artery (MCA) flow velocity was continuously monitored during smoking in an observational study (n = 14) using transcranial Doppler (TCD) ultrasonography. Cerebral autoregulatory vasodilator capacitance under inspired CO2 challenge was also measured before smoking and at peak smoking effect. Several puffs on a single lighted cigarette over a period of five minutes acutely increased MCA mean flow velocity in every subject (group mean increase: 19%, individual increases ranged 2-64%) with a response onset and offset detectable within several seconds of beginning and ending smoking. The mechanism for the increase in MCA flow velocities appeared to be independent of the CO2 autoregulatory mechanism. Gender subgroup analysis showed smoking acutely suppressed the CO2 vasodilator capacitance by 56% in men but only by 5% in women (p = 0.05). The magnitude of the acute smoking-induced increases in MCA flow velocities appeared to be independent of the estimated cigarette yields for nicotine, carbon monoxide, and "tar." Smoking in healthy subjects acutely increased MCA mean flow velocity, which may reflect a global increase in cerebral blood flow via complex influences on the cerebral autoregulation.     

Cerebrovascular reactivity to l-arginine in the anterior and posterior cerebral circulation in migraine patients

Perko D, Pretnar‐Oblak J, Šabovič M, Žvan B, Zaletel M. Cerebrovascular reactivity to l‐arginine in the anterior and posterior cerebral circulation in migraine patients.
Acta Neurol Scand: 2011: 124: 269–274.
© 2011 John Wiley & Sons A/S. Objective – Cerebral infarction preferentially affects the posterior cerebral artery distribution in migraine patients. The results obtained from the few known studies that have compared the anterior and posterior cerebral endothelial function are contradictory. To the best of our knowledge, cerebrovascular reactivity to L‐arginine (CVR), measured by transcranial Doppler sonography (TCD), has not been previously used to determine the posterior cerebral endothelial function in migraine patients with (MwA) and without aura (MwoA). Materials and methods – Forty migraine patients without comorbidities (20 MwA, 20 MwoA) and 20 healthy subjects were included. By employing strict inclusion criteria, we avoided the possible vascular risk factors. Mean arterial velocity in the middle cerebral artery (MCA) and the posterior cerebral artery (PCA) was measured by TCD before and after infusion of L‐arginine, and CVR to L‐arginine was then calculated. Results – All migraine patients had lower CVR to L‐arginine in PCA (P = 0.002) and similar in MCA (P = 0.29) compared to healthy subjects. This difference was also present in MwA and MwoA compared to healthy subjects (P = 0.003). Conclusions – Lower CVR to L‐arginine in PCA in migraine patients could associate migraine and cerebral infarcts that are more common in the posterior cerebral artery distribution.     

溶纤、抗凝、解聚治疗急性脑梗死微栓子监测

目的应用多通道（multi－Depx4）TCD（经颅多普勒）对急性脑梗死应用溶纤、抗凝、解聚治疗时对脑微栓子监测。方法2MHz监测探头,应用鼻架式支架,固定于两侧颞窗,探测左右MCA（大脑中动脉）监测30分钟。结果1组常规药物治疗组33例,微栓子（MES）阳性者22例．占66．7％。Ⅱ组应用降纤酶或尿激酶溶纤或肝素抗凝治疗共18例,MES阳性者4例,占22．2％。Ⅲ组服用阿斯匹灵解聚治疗32例．MES阳性者5例占15．6％。Ⅱ、Ⅲ组MES阳性共9例占18％。Ⅳ组正常健康对照组30例．MES皆阴性。结论多通道MDX4型TCD进行MES监测急性脑梗死应用溶纤、抗凝、解聚药物,MES发生率下降,占18％．而一般治疗MES发生率高．占66．7％,急性脑梗死和对照组相比,MES阳性率为36．14％。     

高凝状态相关性非单一动脉供血区多发急性脑梗死的临床特点和微栓子监测

目的 研究高凝状态相关性非单一动脉供血区多发急性脑梗死的临床和影像学特点、微栓子监测,探讨其可能的发病机制。方法 收集就诊于我院神经内科的高凝状态相关性非单一动脉供血区多发急性脑梗死患者的临床资料、实验室检查、头MRI、TCD微栓子监测,总结分析其特点。结果 共收集22例患者。均以局灶性神经功能缺损急性起病,包括偏瘫、失语、偏身感觉障碍、构音障碍、偏盲、皮质盲。高凝状态相关性基础疾病如下:系统性恶性肿瘤10例,高同型半胱氨酸血症(中重度,HCY50μmol/L)5例,肾病综合征2例,抗磷脂综合征2例,溃疡性结肠炎1例,真性红细胞增多症1例,阵发性睡眠性血红蛋白尿症1例。18例在卒中发病后高凝状态相关性基础疾病才被首次确诊。DWI示多发急性梗死灶,不符合单一动脉供血区,累及双侧前循环或前后循环,病灶累及大脑半球脑叶皮层/皮层下22例,深部12例,小脑10例,脑干2例。22例行微栓子监测者10例阳性。结论 对于非单一动脉供血区多发急性脑梗死,要注意筛查高凝状态相关性基础疾病,高凝状态和微栓塞可能都参与其发病机制。     

Transcranial Doppler evaluation of cerebral infarction in the neonate

We recorded cerebral artery flow velocities (CAFV) in two neonates with cerebral infarction, using transcranial Doppler sonography (TCD). Cerebral infarction was diagnosed by brain imaging. The arteries investigated were the middle cerebral artery (MCA), the internal carotid artery (ICA) and the anterior cerebral artery (ACA). The whole territory of right MCA was involved. A decrease in CAFV was noted in MCA and ICA of the affected side. Furthermore, early recordings of CAFV allowed us to distinguish perinatal infarction from antenatal infarction: in the former, Doppler signal was completely absent during the first days of life whereas in the latter, Doppler signal was reduced but present. The process of recanalization could be followed. The asymmetry of CAFV recorded in the neonatal period seems to persist definitively at least in MCA. These Doppler data correlate well with the evolutive stages of cerebral infarction shown by brain imaging. Beside US, CT and MRI scans, TCD may be a useful adjunct for identifying and following infants with suspected occlusion of major cerebral vessels.     

Evaluation of cerebral intravascular blood flow by time density curve study of intravenous digital subtraction angiography]

Time density curve (TDC) can be reconstructed from the data of intravenous digital subtraction angiography (IVDSA). We evaluated peak time (PT) and modal transit time (MOTT) of the TDC as the probable indicator of cerebral intravascular blood flow. Cerebral IVDSA and single photon emission CT (SPECT) were performed on 12 patients of ischemic cerebrovascular disease, which consisted of 3 internal carotid artery (ICA) occlusions, one middle cerebral artery (MCA) occlusion, one anterior cerebral artery (ACA) branch occlusion and 7 lacunar infarctions. We classified former 4 patients as occlusion group and latter 8 as reference group. In 3 patients (2 ICA and one MCA occlusions), SPECT study revealed definite hypoaccumulation in the MCA territory of occlusive side. Two regions of interest (ROI) were placed on the territories of right and left middle cerebral arteries in the frontal view of cerebral IVDSA. Digital data processor fitted gamma curve to the TDC of each ROI, and calculated PT and MOTT. The absolute lateralities of PT and MOTT of MCA territory was significantly (p less than 0.05) larger in occlusion group than reference group. Patients with hypoaccumulation in SPECT had significantly (p less than 0.02) larger laterality of MOTT than patients with isoaccumulation. One ICA occluded patient without hypoaccumulation in corresponding MCA territory had relatively small laterality of MOTT similar to the patients of ACA branch occlusion and lacunar infarction. These results suggest that PT and MOTT are possible to detect the laterality of the intravascular blood flow in MCA territories caused by major artery occlusion.(ABSTRACT TRUNCATED AT 250 WORDS)     

大脑中动脉狭窄与其深穿支供血区单发脑梗死的关系

目的 分析大脑中动脉(MCA)深穿支供血区单发脑梗死的形态学表现,进一步探讨其与MCA狭窄的关系.方法 连续入选2005年1月至2006年12月于北京协和医院神经科住院治疗急性脑梗死,并经头颅DWI检查明确急性梗死灶为单发,且位于MCA深穿支供血区域的55例患者;所有患者均行TCD和MRA检查,颅外颈内动脉狭窄>50%以及有可疑心源性栓子来源的患者从研究中排除.根据是否存在病灶同侧MCA狭窄将入选患者分为两组:MCA狭窄组(14例)与MCA正常组(41例).测量DWI上急性梗死灶的直径、面积和体积,并将直径≤2 cm归为经典腔隙性梗死,直径>2 cm归为纹状体内囊梗死.DWI上的梗死灶区分为基底节区、侧脑室体旁和同时累及上述2个部位,并判断MRI T2>像上皮质下多发陈旧性小梗死灶或白质疏松是否存在.结果 55例患者中,病灶侧MCA狭窄患者14例(25.5%),MCA正常患者41例(74.5%).MCA狭窄组中经典腔隙性梗死占71.4%,MCA正常组中经典腔隙性梗死占67.3%,差异无统计学意义(χ2=0.147,P=0.701).MCA狭窄组与正常组患者MCA深穿支梗死病灶的大小(包括直径、面积及体积)差异均无统计学意义.MCA正常组和MCA狭窄组病灶在基底节区、侧脑室体旁及基底节区+侧脑室体旁分布的比例依次为:正常组31.7%、17.1%和51.2%;狭窄组35.7%、28.6%和35.7%,两组间差异无统计学意义(χ2=1.272,P=0.529).同时存在皮质下多发陈旧性小梗死灶或白质疏松的患者在MCA正常组有23例(56.1%),在MCA狭窄组有3例(21.4%),二者差异有统计学意义(χ2=5.033,P=0.025).结论 MCA深穿支供血区梗死具有不同的发病机制,MCA狭窄和穿支动脉本身病变均可造成深穿支供血区单发脑梗死.梗死灶的大小、体积及梗死发生的部位与是否存在同侧大脑中动脉狭窄无明显相关性,而同时存在皮质下多发陈旧性小梗死灶或白质疏松对穿支动脉病变有提示作用.     

The relation between cerebral blood flow velocities as measured by TCD and the incidence of delayed ischemic deficits. A prospective study after subarachnoid hemorrhage

Patients (n = 127) with aneurysmal subarachnoid hemorrhage (SAH) were examined by transcranial Doppler ultrasonography (TCD) in a prospective study to follow the time course of the posthemorrhagic blood flow velocity in both the middle cerebral artery (MCA) and in the anterior cerebral artery (ACA). Results were analysed to reveal their relationship and predictive use with respect to the occurrence of delayed ischemic deficits. Mean flow velocities (MFV) higher than 120 cm sec(-1) in MCA and 90 cm sec(-1) in ACA were interpreted as indicative for significant vasospasm. In 20 of our 127 patients (16%) a delayed ischemic deficit (DID) was subsequently diagnosed clinically (DID+ group). Patients in the DID+ group can be characterized as those individuals who presented early during the observation period post-SAH with highest values of MFV, a faster increase and longer persistence of pathologically elevated MFV-values (exceeding 120 cm sec(-1) in MCA and 90 cm sec(-1) in ACA). They also show a greater difference in MFV-values if one compares the operated to the nonoperated side. Differences in MFV-values obtained in MCA or ACA were statistically significant (p < 0.05) for DID+ and DID- patients. The daily maximal increase of MFV was found between days 9 and 11 after SAH. In the DID+ group, the maximal MFV was 181 +/- 26 cm sec(-1) in MCA and 119 +/- 14 cm sec(-1) in ACA. In contrast to this, patients in the DID- group were found to present with MFV of 138 +/- 11 cm sec(-1) in MCA and 100 +/- 7 cm sec(-1) in ACA respectively. Delayed ischemic deficits appeared three times more often in DID+ patients than in patients with MFV < 120 cm sec(-1), if they showed a MFV > 120 cm sec(-1) in MCA. If pathological values were obtained in ACA, this ratio increases to about four times, if DID + patients presented with MFV > 90 cm sec(-1) versus patients with MFV < 90 cm sec(-1). Daily monitoring of vasospasm using TCD examination is thus helpful to identify patients at high risk for delayed ischemic deficits. This should allow us to implement further preventive treatment regimens.     

Bleeding and subsequent anemia: a precipitant for cerebral infarction

BACKGROUND AND OBJECTIVES: The relationship between bleeding and subsequent anemia (BSA) and the occurrence of stroke has not been sufficiently studied. The purpose of the present study was to elucidate the characteristics of stroke associated with BSA. METHODS: We studied 16 consecutive patients with acute stroke associated with anemia (hemoglobin level on admission < or =9.0 g/dl) and compared their stroke subtypes with those of 32 control subjects. RESULTS: The cause of anemia was upper gastrointestinal bleeding in 11 patients (ulcers in 8; carcinomas in 2, and hemorrhagic gastritis in 1), bleeding from a hemorrhoid in 2, uterine cervical bleeding in 1, ecchymosis probably related to medication in 1, and chronic blood drainage in 1. At least 10 patients had a history of recent (<1 week), active bleeding. Clinical and imaging studies showed that all the patients had infarcts and none had intracerebral hemorrhages. Thirteen patients had infarcts in the region of the middle cerebral artery (MCA) (total MCA region in 2; partial, cortical area in 5; subcortical area in 5, and lenticulostriate artery region in 1), 2 had anterior cerebral artery (ACA) region infarction, and 1 had cerebellar infarction. All 11 patients who underwent vascular imaging studies showed significant stenosis and/or occlusion of the internal carotid artery (ICA) (n = 5), the MCA (n = 4), both the ICA and MCA (n = 1), or the ACA (n = 1). Of the different stroke subtypes (large vessel infarction (LVI), small vessel infarction, cardiogenic embolic infarction, intracerebral hemorrhage), LVI was significantly (p<0.05) more frequent in patients with stroke associated with BSA than in the controls, even though the demographics and risk factors were similar in each group. CONCLUSIONS: The close temporal relationship between the bleeding and the onset of stroke, as well as the predominance of the LVI subtype in the BSA-associated group as compared to controls, suggest that BSA may precipitate atherothrombotic cerebral infarction. A hemodynamic alteration, enhanced thrombosis or a combination of these appears to be the pathogenic mechanism.     

Dynamics and embolic activity of symptomatic intra-cranial cerebral artery stenoses

OBJECTIVE: To investigate the occurrence of microembolic signals (MES) and hemodynamic features in patients with acute symptomatic intracranial cerebral artery stenoses by transcranial Doppler (TCD). MATERIAL AND METHODS: Twelve patients with acute hemispheric ischemic events and corresponding intracranial cerebral artery stenoses as identified by TCD, and exclusion of extracranial or cardiac emboli sources were repeatedly studied by TCD monitoring of the affected and the contralateral vessel. The occurrence of MES and MES clusters (> or =3 MES per second) and of flow velocity changes was examined. RESULTS: Nine patients presented with MES in the affected artery during the first measurement. In seven patients sudden flow velocity changes could be detected in the affected vessel. In five patients these changes were accompanied by MES clusters. MES and velocity changes disappeared in all patients during follow-up, and the degree of stenosis decreased in nine patients. CONCLUSIONS: The high prevalence of MES and sudden velocity changes in acute intracranial cerebral artery stenoses indicates that acute intracranial stenoses may be formed at least in part by mobile thrombotic material.     

The Role of Transcranial Doppler in Symptomatic Striatocapsular Small Deep Infarction

BACKGROUND AND PURPOSE: The transcranial Doppler (TCD) findings in symptomatic small deep infarction are not well known. The aim of this study was to evaluate the role of TCD in striatocapsular small deep infarctions (SSDIs). METHODS: The cerebral angiography and TCD findings were analyzed on 100 patients with symptomatic cerebral infarcts on the middle cerebral artery (MCA) territory. The sensitivity, specificity, and accuracy of TCD in detecting the MCA lesions were compared between lacunar group (the patients with lacunar syndrome and SSDIs on magnetic resonance image) and nonlacunar group. RESULTS: Thirty-eight patients were classified as the lacunar group, whereas 62 patients as the nonlacunar group. On angiography, occlusive lesion of MCA was found in 18 of the lacunar group and 24 patients of the nonlacunar group. The degree of MCA stenosis was higher in the nonlacunar group (80.8% +/- 21.2%) than the lacunar group (60.4% +/- 21.6%). The accuracy of TCD for the detection of MCA stenosis was not different between the groups. However, the sensitivity of TCD in the lacunar group was lower (72%) than in the nonlacunar group (88%), and it might have been due to the difference in the degree of MCA stenosis among the groups. CONCLUSION: Occlusive lesions of the MCA should be considered as a potential cause of SSDIs. In this respect, TCD may be used for screening candidates for conventional angiography in those patients. High rate of mild-degree stenosis of MCA in patients with SSDIs, however, caused a risk for missing such stenosis on TCD.     

CBF and transcranial Doppler sonography during vasodilatory stress tests in patients with common carotid artery occlusion.

Cerebral blood flow (CBF) and the cerebral vasoreactivity was measured in patients with cerebrovascular disease and longstanding occlusion of the common carotid artery (CCA). In addition, regional CBF was correlated with transcranial doppler (TCD) measurements at baseline and during 6% CO2 inhalation and after intravenous administration of 1 g of acetazolamide. Twelve patients with a mean age of 62 years (range 45 to 71 years) were included, and the data compared to age-matched healthy controls. CBF was measured by intravenous injection of xenon-133 and SPECT (Tomomatic 564). TCD of the middle cerebral artery (MCA) was done by EME TC-64B. A very low global CBF value of 28 +/- 5 (SD) ml 100 g-1 min-1 was found at baseline as compared to 55 +/- 5 ml 100 g-1 min-1 in the normal controls. During 6% CO2-inhalation and after acetazolamide administration, CBF increased by 58 +/- 24% and 51 +/- 21%, respectively, indicating substantial collateral supply. Correlative analysis of CBF in the MCA territory and TCD in the MCA showed statistical significance only for the pooled data, i.e. compiling the data obtained during baseline and the two vasodilatory tests, and then only for the mean and peak TCD velocity (e.g. r = 0.59, p less than 0.002, n = 35, mean velocity, right side). We conclude that TCD measurements do not predict regional CBF in patients with CCA occlusion. The study emphasizes that these two methods yield supplementary information, with TCD measurements providing information of the circle of Willis and CBF studies of the flow distribution.     

Assessment of ophthalmic artery collateral pathway in the hemispheric cerebral hemodynamics in patients with severe unilateral carotid stenosis

The role of ophthalmic artery collateral pathway in hemispheric hemodynamics in patients with severe carotid stenosis is controversial. The aim of the present study was to address this question comparing the asymmetry of the velocity in middle and anterior cerebral arteries (MCAs and ACAs) and cerebrovascular reactivity (CVR) in MCA on stenotic side in the patients with unilateral severe stenosis of internal carotid artery (ICA) in patients with and without ophthalmic artery collateral pathway. The cohort of 118 patients with carotid stenosis was prospectively assembled. Fifty patients who had severe unilateral ICA stenosis (71%-99%) by Duplex Ultrasound (DUS) were observed by transcranial Doppler (TCD). Cerebral blood flow velocity in MCA and ACA in both sides, direction of blood flow in ophthalmic artery (OA) and CVR on the side of stenosis were determined. There were 14 patients with retrograde blood flow in OA (Group I). The remaining 36 patients with anterograde flow in OA composed Group II. The degree of interarterial asymmetry of peak and mean velocity (Vpeak and Vmean) in MCA and ACA and CVR in MCA were compared in both groups. The degree of ACA asymmetry by Vpeak was 44.0% +/- 6.9% in Group I and 38.3% +/- 3.9% in Group II (p = 0.49), by Vmean 40.3% +/- 6.7% and 36.6% +/- 3.8% (p = 0.63) respectively. The degree of MCA asymmetry by Vpeak was 24.2% +/- 2.8% in Group I and 19.5% +/- 5.0% in Group II (p = 0.42), by Vmean 23.5% +/- 2.9% and 20.6% +/- 5.1% (p = 0.63) respectively. CVR in Group I was 26.1% +/- 6.1%, in Group II 29.0% +/- 6.7% (p = 0.65). The ophthalmic collateral pathway has no influence on hemispheric cerebral hemodynamics in patients with severe unilateral carotid stenosis.     

Micro embolic signals in patients with cerebral ischaemic events

The aim of this study was to evaluate the occurrence of micro embolic signals (MES) in patients with a cerebral ischaemia using transcranial doppler monitoring and to find out its diagnostic relevance. We prospectively performed bilateral multigated transcranial doppler monitoring from both middle cerebral arteries in 359 patients with an acute or recent (<4 weeks) cerebral ischaemic event, and in 182 control subjects without a cerebral ischaemic event. MES were analysed according to the standardised protocol. Patients with cerebral ischaemic events had a significantly higher (p<0.00001) rate of MES occurrence (31.8%) than control subjects (5.5%). MES were detected significantly higher in patients with partial or total anterior circulation infarcts (39.1%) than in those with lacunar infarcts (26.0%) or transient ischaemic attacks (27.3%). A correlation of MES and neuroimaging finding was also tried. TCD was found to have a predictive role in microemboli monitoring, predominantly in patients with large vessel territory infarction.