Cerebral vasomotor reactivity in Parkinson's disease, multiple system atrophy and pure autonomic failure

Parkinson's disease (PD), multiple system atrophy (MSA) and pure autonomic failure (PAF) are neurodegenerative disorders frequently associated with orthostatic hypotension and syncope, though with different underlying mechanisms. Cerebral hemodynamic responses in these three neurodegenerative diseases are still incompletely studied and it is possible that they would be differentially affected. We measured blood flow velocity (BFV) in the middle cerebral artery (MCA) and vertebral artery (VA) in patients with these disorders and investigated whether cerebral vasomotor reactivity (VMR) differs in these three disorders. Twenty-four patients (9 with PD, 10 with MSA and 5 with PAF) were studied. VMR was assessed in the MCA and VA, using transcranial Doppler (TCD) and Diamox test (injection of 1 g acetazolamide i.v.) with the patients in a recumbent position. The percent difference between BFV before and after acetazolamide injection was defined as VMR% and the results were compared by ANOVA. The mean MCA and VA blood flow velocities were similar in the three disorders and within normal limits for our laboratory. The mean MCA VMR values were 37.5+/-24.0%, 27.9+/-28.0% and 38.0+/-33.9% in PD, MSA and PAF, respectively. The VA VMR values were 22.9+/-23.6%, 32.4+/-38.0% and 18.9+/-18.3%, respectively, with no significant differences between the groups. We conclude that BFV is normal in PD, MSA and PAF and that the VMR, as investigated by TCD and the Diamox test, did not disclose differences in cerebral vasomotor responses between these conditions.     

Transcranial Doppler in infantile cerebrospinal fluid disorders: clinical validity

The present study was designed to investigate a possible relationship between transcranial Doppler sonography (TCD) parameters with infantile hydrocephalus and other types of cerebrospinal fluid (CSF) abnonnalities, i.e. arrested hydrocephalus and essential ventriculomegaly. TCD parameters in the major arteries of the circle of Willis were studied in hydrocephalic children (n = 12) before and after insertion of a ventricular shunt device. It was correlated with TCD parameters of children with CSF disorders (n = 13), in whom no surgery was performed. Also, TCD parameters were assessed in control cases (n = 10). Mean values for medial cerebral artery (MCA) flow velocities were higher in the essential ventriculomegaly (75.38 +/- 4.1) and in the control group (73.93 +/- 3.4) compared with hydrocephalic children (64.13 +/- 5.3). All hydrocephalic children had a higher mean MCA pulsatility index (RI) (1.08 +/- 0.13) and resistance index (RI) (0.64 +/- 0.17) values than the essential ventriculomegaly group (PI: 1.03 +/- 0.48; RI: 0.63 +/- 0.13) and the control group (PI: 0.84 +/- 0.32; RI: 0.57 +/- 0.23). Analysis of all TCD parameters disclosed its usefulness only after a particular and thorough evaluation of the TCD results with special emphasis in the clinical correlation of every case.     

Sonographic assessment of the optic nerve and the central retinal artery in idiopathic intracranial hypertension

PurposeTransorbital sonography easily detects papilledema and enlarged optic nerve sheath diameters (ONSD) in IIH (idiopathic intracranial hypertension) patients. As the central retinal artery is located within the optic nerve, its hemodynamic properties might be affected by the increased pressure. In this study we assessed the diagnostic usefulness of transorbital sonography in IIH with a special focus on color Doppler imaging of the central retinal artery. IIH patients presented papilledema and enlarged ONSD. ONSD accurately predicted an increased intracranial pressure in IIH (cut-off: 5.8 mm, 81% sensitivity, 80% specificity). 24 h following therapeutic lumbar puncture ONSD diminished significantly, whereas papilledema was not changed. PSV (peak systolic velocity) and Vmean (mean flow velocity) of the central retinal artery were increased in IIH patients compared to controls. PSV accurately predicted an increase of intracranial pressure (cut-off: 11.0 cm/s, 70% sensitivity, 69% specificity). PI (pulsatility index), PSV and Vmean decreased following lumbar puncture. PSV and Vmean decreases were statistically significant for right eyes only in which the values changed to normal. In summary, besides ONSD enlargement and papilledema transbulbar sonography demonstrated an alteration of central retinal artery blood flow in IIH patients. Especially PSV might serve as valuable surrogate marker for intracranial pressure in IIH. Furthermore, the change of intra-individual central retinal arteries PI might be a valuable parameter to demonstrate response to lumbar puncture in IIH patients.     

Evaluation of blood flow velocity and cerebrovascular reactivity in patient with posterior circulation stroke

The aim of our study was to determine the type of blood flow disturbances and cerebrovascular reactivity of major anterior and posterior circulation cerebral vessels in patients with posterior stroke (POCI). The examined group consisted of 17 patients, mean age 57 +/- 12 yr, with posterior circulation infarct. Neurological examination, brain CT and Doppler examination including evaluation of BFV and CVR of MCA, PCA and VA was performed in each patient. Doppler examination was done using Pioneer TC 2020 and capnograph Tidal Wave sp Novametrix. RESULTS: BFV of ICA's, MCA's, ACA's and PCA's were diminished while BFV of VA's were significantly diminished in the examined patients compared to healthy controls. CVR of MCA in posterior circulation stroke patients was significantly lower compared to controls. CVR of PCA and VA was significantly lower compared to CVR of MCA in patients with posterior circulation stroke. CONCLUSION: Impairment of CVR, especially in posterior circulation, plays an important role in posterior circulation stroke pathogenesis.     

Effect of changes in optic nerve elasticity on central retinal artery blood flow in patients with idiopathic intracranial hypertension

PurposeTo assess changes in central retinal artery (CRA) blood flow by orbital color-coded Doppler ultrasonography in patients with idiopathic intracranial hypertension (IIH) and their relation with optic nerve (ON) elasticity assessed by shear wave elastography (SWE).MethodsThis study was carried out on 68 eyes of patients diagnosed with IIH and 32 eyes of healthy controls. The severity of papilledema in IIH patients was sub-classified into mild and moderate/severe groups. Color-coded Doppler was used to measure peak systolic velocity (PSV), end diastolic velocity (EDV), mean velocity (V_mean) and pulsatility index (PI) of the CRA.ResultsPSV, V_mean, and SWE were significantly higher in patients with IIH than in controls (p = 0.001). The optimal cut-off values of PSV and V_mean for differentiating IIH patients from controls were 11.25 and 6.75 cm/s with AUC 0.81 and 0.785 respectively. AUC was 0.92 and accuracy 91% for combined PSV, V_mean and SWE differentiation between IIH patients and controls. PSV, V_mean and SWE were significantly different between mild versus moderate/severe papilledema (p = 0.001). PSV and V_mean were correlated with papilledema (r = 0.790 and 0.722 respectively) and SWE (r = 0.818 and 0.761 respectively).ConclusionIIH is associated with decreased ON elasticity and reduced CRA blood flow. Individual and combined color-coded Doppler of the CRA and SWE help in diagnosis of IIH. CRA hemodynamic changes are correlated with papilledema severity and with the extent of biomechanical changes in the ON represented by SWE.     

Cerebrovascular CO2 reactivity in migraine with aura and without aura. A transcranial doppler study

Inntroduction – We studied by means of Transcranial Doppler (TCD) recordings the CO₂ cerebrovascular reactivity in migraine patients during the headache-free period. Material & methods - In three groups of subjects (15 controls, 15 suffering from migraine with aura and 15 from migraine without aura) the middle cerebral artery (MCA) mean flow velocity (MFV) was recorded under basal condition and hypocapnia induced by hyperventilation. Relative MFV, PI (Pulsatility Index) changes and Reactivity Index (RI) were calculated. Results - Reactivity Index values were: 0.019 ± 0.007 (mean ± SD) in control subjects: 0.029 ± 0.008 in migraine with aura; 0.022 ± 0.008 in migraine without aura. Statistical analysis showed a significantly (P < 0.05) increased RI in migraine with aura group. Conclusion – Cerebrovascular CO₂ reactivity is increased during the interictal period in migraine with aura patients.     

Effect of cardiovascular disease on hemodynamic response to cognitive activation: a functional transcranial Doppler study

We compared the cerebrovascular response to various cognitive tasks of cardiovascular patients and healthy controls by using transcranial Doppler ultrasonography (TCD). Cognitive task-induced cerebral blood flow velocity (BFV) changes in 66 candidates for coronary artery bypass graft surgery (mean age 59.4 +/- 7.5) were compared with the functional BFV measurement of 60 healthy controls (mean age 58 +/- 7). Absolute BFV values during baseline and activation were monitored with TCD. Relative increase of the BFV was calculated from the immediately preceding rest period to the following activation. A manova with group (patients versus controls) as between-subjects factor showed no differences in absolute BFV during the rest period. For absolute BFV during activation, a significant difference between the two groups was found. Although for each test the percentage change was smaller in the cardiac group, the difference just failed to reach significance. An explorative multivariate linear regression analysis with the absolute activation and percentage change as dependent variables and coronary risk factors as independent variables revealed no significant predictors. Using functional TCD we found that BFV values during activation were significantly lower in cardiac patients compared with healthy controls. Future research should focus on the possible explanations of this phenomenon.     

Cerebral blood flow changes in patients with probable medication-overuse headache

Transcranial Doppler (TCD) is a non-invasive method for measuring blood flow velocity (BFV), and a marker of vessel diameter. In this study, intracranial BFV was investigated, by means of TCD, in patients suffering from probable medication-overuse headache (PMOH). Twenty-three female patients with probable ergotamine- overuse headache (PEOH), 23 female patients with probable analgesic-overuse headache (PAOH), and 15 healthy female controls participated in the study. The mean BFVs of the bilateral middle and anterior cerebral arteries (MCA and ACA) and basilar artery (BA) were measured by TCD. The mean BFVs of the BA and MCA were found to be significantly increased in the PEOH group when compared with those of the PAOH and control groups (p<0.05). No significant differences in BFV of the ACA were observed between any groups (p>0.05). The mean BFV of all the vessels in the PAOH group was found to be lower than that of the control group but no statistical significance was found (p>0.05). Our results show that ergotamine increases BFV via vasoconstriction, especially of the BA and MCA. We also suggest that 5HT1B/1D receptors are mainly localized in the BA and MCA, and that analgesic overuse results in a functional disorder of neuronal receptor and neurovascular reflexes and may cause a reduction of intracerebral vessel tone, leading to vasodilatation.     

Cerebral blood supply with aging: normal, stenotic and recanalized

The prosperity of brain parenchyma during aging depends on the preservation of cerebral blood flow (CBF) parameters. We have analysed ultrasonographic measurements of peak systolic (PSV) and end diastolic velocities (EDV) along with pulsatility (PI) and resistance indexes (RI) in common (CCA), internal (ICA) and external carotid artery (ECA) (N=199) and in vertebral arteries (VA) (N=200) in patients without any signs of stenosis. In two other cohorts patients with internal carotid artery stenosis (N=231) and patients prior to and after therapeutic recanalization (N=81) were evaluated in the same parameters. Results: in the range of 21-92 years PSV in CCA decreases by 7 mm/s/year, while in ICA only by 2.31 mm/s/year. The decrease of EDV in carotid arteries occurs between 1.72 and 2.28 mm/s/year. PSV in VA drops down by 0.91 mm/s/year, EDV by 0.86 mm/s/year. PI and RI increase with age in all vessels, but not significantly. Stenotic ICAs are associated with increased PSV in the range of 0.7-2.9 m/s, but also with an increasing PSV variability along the growing stenosis in individual patients. In all degrees of stenoses some patients preserve normal velocities. In average the increment for each 10% of the stenosis below 50% makes 8 cm/s, while above 50% it makes already 50 cm/s. In persons with bilateral stenoses the increment with growing stenosis is steeper. The restoration of normal ICA lumen by means of carotid endarterectomy or by angioplasty with stenting results in an average drop by 1.23 m/s in PSV and by 0.4 m/s in EDV. We have investigated the ophthalmic artery and other substitution supplies and deduce, that the remarkable differences in blood flow velocity reactions to a compromised carotid lumen depend on the formation of collaterals in mutual interplay with peripheral resistance.     

高血压患者双侧颈动脉血流和形态的偏侧差异性分析

目的探讨高血压对双侧颈动脉血流动力学及动脉壁厚度的影响差异。方法纳入原发性高血压患者52例为高血压组,健康体检者46例为健康组。应用彩色多普勒超声分别检测两组患者左右侧颈总动脉搏动指数(pulsatility index,PI)、阻力指数(resistance index,RI)、动脉血流收缩期峰值(peak systolic velocity,PSV)、舒张末期的谷值(end diastolic velocity,EDV)和内-中膜厚度(intima-media thickness,IMT)。对比两组组内左右侧颈动脉上述指标的差异,以及两组组间同侧颈动脉上述指标的差异。结果高血压组颈总动脉P(IP=0.019)、R(IP=0.012)及IMT(P=0.043)均为左侧大于右侧,而两侧血流速度无显著差异。健康组左右侧颈总动脉上述各项指标均无显著差异。高血压组双侧IMT、RI均显著高于健康组同侧颈总动脉,其中左侧IMT P=0.002,右侧IMT P=0.017,左侧RI P=0.023,右侧RI P=0.024,同时左侧PI高于健康组(P=0.011),而两组间血流速度无显著差异。结论原发性高血压对颈动脉血流动力学及形态学影响左侧大于右侧。     

Optimal Values of Flow Velocity on Transcranial Doppler in Grading Middle Cerebral Artery Stenosis in Comparison With Magnetic Resonance Angiography

BACKGROUND AND PURPOSE: To investigate the optimal values of flow velocity on transcranial Doppler (TCD) in grading the severity of middle cerebral artery (MCA) stenosis in comparison with magnetic resonance angiography (MRA). METHODS: Both TCD and MRA examinations were performed on 148 asymptomatic patients. The peak flow velocities of each MCA were recorded. Severity of MCA stenosis on MRA was classified as normal-mild (< 50% lumen diameter reduction), moderate (50%-75%), and severe-void (> 75% and void of flow signal). RESULTS: Among 296 MCAs evaluated, normal-mild stenosis was found in 75 (25%), moderate stenosis in 112 (38%), and severe stenosis in 109 (37%). The mean of systolic velocity (Vs) of MCA differed significantly among these three groups: mean Vs = 121.83 +/- 22.52 cm/s in the normal-mild group; 155.96 +/- 21.62 cm/s for the moderate group; and 199.39 +/- 43.86 cm/s for the severe group (P < .001). The optimal cutoff velocity for detection of MCA (> 50%) stenosis was found at Vs > 140 cm/s on TCD (area under the ROC curve is 0.87, P < 0.001). The best cutoff points for grading severity of on TCD were 140 cm/s and 180 cm/s. CONCLUSION: TCD enables grading of the severity of MCA stenosis according to the flow velocity. This method provides a noninvasive and reliable method for grading MCA stenosis and allows longitudinal monitoring of the relationship between clinical outcome and hemodynamic change.     

Detection of Stenosis Progression in Intracranial Vertebral Artery Dissection Using Carotid Ultrasonography

Background: The purpose of this study was to assess whether carotid ultrasonography indices detect arterial stenosis progression in patients with vertebral artery (VA) dissection. Methods: This was a retrospective, single-center, observational study that enrolled patients with intracranial VA dissection who were admitted from January 2011 to June 2017. Magnetic resonance angiography (MRA) was done on admission and followed up at a median 20 days after onset (interquartile range [IQR] 9-58 days), and ultrasonography was performed at a median of 22 (interquartile range 7-56) days. Peak systolic velocity (PSV), end-diastolic velocity (EDV), mean velocity (MV), and pulsatility index (PI) were measured by ultrasonography, and the ratio of each follow-up value to the baseline (follow-up/baseline) value was calculated. Two stroke neurologists categorized into 3 groups by morphological changes of the dissected vessel: patients with stenosis progression (progression group: P-group); those with no remarkable change or dilatation improved (stable group: S-group); and those with stenosis regression or dilatation enlargement (enlargement group: E-group). Ultrasonography indices were compared among the groups. Results: Of the 42 patients who were enrolled to this study, 39 patients underwent ultrasonography and MRA on both admission and follow-up. The PI ratio was significantly higher in the P-group than in the S-group (1.96 ± .80 versus .98 ± .44, P = .02) and in the E-group (versus .65 ± .35, P < .01). There were no significant differences in the PSV ratio, EDV ratio, and MV ratio. Conclusions: In patients with VA dissection, the PI ratio on ultrasonography is a promising index to detect stenosis progression.     

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.     

Cerebral autoregulation is preserved in multiple system atrophy: A transcranial Doppler study.

Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.     

眼-颈一体超声在特发性颅内压增高及颅内静脉窦血栓中的应用价值

目的 研究眼部超声及颈静脉超声在特发性颅内压增高(ⅡH)及颅内静脉窦血栓(CVST)中的应用价值.方法 回顾性纳入2017年1月至2019年12月于吉林大学白求恩第一医院神经内科住院治疗的新诊断的IIH患者20例、CVST患者25例,所有的患者需完成眼部超声及颈部静脉超声检查.收集年龄、性别和BMI匹配的对照组40例....     

The effects of hematocrit and age on transcranial Doppler measurements in patients with recent ischemic stroke

BACKGROUND: The effects of age and hematocrit on transcranial Doppler (TCD) velocities have not been evaluated in a large patient group with recent ischemic stroke. AIM: This study assessed the effects of age and hematocrit on TCD measurements in patients with recent ischemic stroke compared to patients with non-vascular diseases. SETTINGS AND DESIGN: University Hospital, retrospective study. MATERIALS AND METHODS: TCD records and data files of 862 consecutive patients (mean age, 57+/-16 years) with various neurological diagnoses were reviewed retrospectively. The peak systolic, end diastolic and mean flow velocities (FV), systolic/diastolic ratios and pulsatility indices (PI) in the middle cerebral arteries were averaged and the effect of age and hematocrit values on these TCD values was studied. Independent samples t test, Pearson's coefficients of correlation, and linear regression test were used for statistical analysis. RESULTS: Among 862 patients, 413 were women (mean age, 53+/-17 years) and 449 were men (mean age, 60+/-13 years). Peak systolic and mean FV were higher and hematocrit concentration was lower in women compared to men (P< 0.001). The relation of TCD velocities with age and hematocrit was more remarkable in the group of patients with non-vascular neurological disorders. PI values demonstrated a significant correlation to age (r=+0.47) (P< 0.001), but did not change significantly with hematocrit level. CONCLUSIONS: It should be remembered that blood FV measured by TCD may be significantly affected by age and hematocrit level. However, there seems to be no significant association between TCD velocities and hematocrit in patients with a recent ischemic stroke.     

Noninvasive Ultrasound Evaluation of the Vertebral Artery in Hypertension

BACKGROUND AND PURPOSE: Surgical decompression of the vascular loop of the vertebral artery (VA) at the left lateral medulla can reduce blood pressure (BP) in hypertension, and a larger diameter of the left VA has been found in hypertensive patients. Noninvasive evaluation of the VA in hypertension may assist selecting patients for more appropriate diagnosis and treatment. Duplex ultrasonography is used to study the relationship between VA diameter and BP. METHODS: A retrospective review of VA duplex ultrasonography was performed in 112 consecutive patients who were sent to the neurovascular laboratory at the Wake Forest University School of Medicine during a 2-month period. All measurements (BP, pulse rate, peak systolic velocity [PSV], end diastolic velocity [EDV], and diameters of both VAs) were determined according to standardized protocols. Left-right comparisons of VA diameters, PSV, and EDV between hypertensives and normotensives were performed by the matched-pairs analysis techniques. RESULTS: Fifty-five women and 57 men with a mean age of 64.8 years were studied. Hypertension was present in 65.2% of all patients. The age-adjusted mean left VA diameter was significantly higher than that of the right VA with an age-adjusted average differences of 0.2 mm (P = .03) for hypertensives compared to 0.04 mm (P = .75) for normotensives. No significant differences were observed in either PSV or EDV. CONCLUSIONS: Differences in left-right VA diameter in hypertensive subjects may be a previously unrecognized component of the vascular disturbances associated with the disease and represent an additional criterion for identifying those who may benefit from surgical and medical management.     

高血压合并无症状性大脑中动脉狭窄患者的药物干预研究

目的探讨在降血压治疗的同时联合应用辛伐他汀和阿司匹林对高血压合并无症状性大脑中动脉狭窄患者的干预作用和脑血管事件的预防效果。方法177例高血压合并大脑中动脉狭窄患者,其中90例应用辛伐他汀(每晚20mg)和阿司匹林肠溶片(75mg/d)进行治疗(干预组),通过经颅多普勒超声检查分别观察治疗前及治疗后1～3年大脑中动脉收缩期血流速度峰值、搏动指数、阻力指数、频谱形态,同时检测治疗前后血压、血脂等项生化指标的变化,并与87例对照者进行比较。结果治疗第1年,干预组患者大脑中动脉收缩期血流速度峰值、搏动指数、阻力指数及频谱形态等与治疗前差异无统计学意义(P>0.05);随访至第2,3年,上述各项指标均改善(P<0.01),频谱形态明显好转。随访结束时,两组患者大脑中动脉上述指标间差异有高度统计学意义(均P<0.01),干预组患者脑血管事件发生率为11.11%(10/90),低于对照组的24.14%(21/87)(P<0.01)。结论在有效降低血压的同时,联合应用辛伐他汀和阿司匹林可稳定并延缓高血压患者大脑中动脉狭窄的进程,对降低脑血管事件的发生率具有良好的作用。     

经颅多普勒超声诊断脑动脉痉挛与数字减影血管造影的对比研究

目的探讨经颅多普勒超声(TCD)诊断大脑中动脉(MCA)、椎动脉(VA)、基底动脉(BA)痉挛的可靠性。方法对50例蛛网膜下腔出血患者同时行TCD和数字减影血管造影(DSA)检查并进行对比分析。结果DSA发现MCA痉挛26条，其中TCD检出21条，DSA未证实有痉挛的MCA中，TCD检出4条，TCD诊断MCA痉挛的敏感性为80．8％，特异性为84．0％，而且MCA痉挛程度越重，TCD敏感性越高。DSA发现BA痉挛18条，其中经TCD检出13条，DSA未证实有痉挛的BA中，TCD检出4条，TCD诊断BA痉挛的敏感性为72．2％，特异性为76．5％。DSA发现VA痉挛28条，其中经TCD检出20条，DSA未证实有痉挛的VA中，TCD检出6条，TCD诊断VA痉挛的敏感性为71．4％，特异性为76．9％。结论TCD诊断MCA、VA、BA痉挛有较高的可靠性。     

急性脑梗死各临床亚型患者的脑血管反应性的变化

目的 探讨急性脑梗死各临床亚型患者脑血管反应性(CVR)的变化.方法 将70例急性脑梗死患者分为3个亚组:动脉硬化性血栓形成性脑梗死(AI)组(22例)、腔隙性脑梗死(LI)组(33例)和心源性脑梗死(CI)组(15例).应用经颅多普勒超声(TCD)检测各组患者双侧大脑中动脉(MCA)的平均流速(Vm)、脉动指数(PI)、阻力指数(RI)指标,通过屏气试验测定屏气指数(BHI);并与20名正常对照组进行比较. 结果与正常对照组相比,AI组Vm、PI、RI均显著升高(P<0.05～0.01),BHI明显降低(P<0.01);LI组Vm、BHI均显著降低(均P<0.05);而CI组各参数与正常对照组相比差异无统计学意义. 结论急性脑梗死各亚组的CVR改变并不相同,AI、LI组CVR损害更为明显,CVR检测对急性脑梗死各亚型的血液动力学研究有重要意义.