Fetal adrenal and middle cerebral artery Doppler velocimetry in high-risk pregnancy.

OBJECTIVES: Animal studies have shown that hypoxic fetuses redistribute their blood flow, giving preferential supply to the brain, heart and adrenal glands. The aim of this study was to establish whether blood velocity waveforms in the human fetal adrenal artery and middle cerebral artery showed signs of redistribution of fetal circulation in high-risk pregnancy, and to analyze the relationship between signs of such redistribution and the outcome of pregnancy. METHODS: Fetal middle adrenal artery and middle cerebral artery waveforms were recorded between 27 and 41 weeks of gestation in 102 pregnancies complicated by pregnancy-induced hypertension. Signs of fetal adrenal-sparing were deemed present when the pulsatility index (PI) fell below the fifth percentile of the normal range. Signs of fetal brain-sparing were deemed present when the cerebral artery PI was below the mean -2 SD of the normal range and the cerebroplacental PI ratio was < 1.08. RESULTS: Signs of adrenal sparing were found in 64 cases and brain sparing in 32 cases. Fetal adrenal sparing was strongly associated with adverse perinatal outcome; all perinatal mortality cases showed signs of adrenal sparing. There was a significant positive correlation between the fetal adrenal artery PI and umbilical arterial and venous pH. CONCLUSIONS: Signs of adrenal sparing are frequent in high-risk pregnancies. Adrenal artery velocimetry may be a useful procedure for fetuses at risk for hypoxemia.     

Uterine and fetal cerebral Doppler predict the outcome of third-trimester small-for-gestational age fetuses with normal umbilical artery Doppler.

OBJECTIVE: To assess the value of different admission tests in predicting the outcome of small-for-gestational age (SGA) fetuses with normal Doppler waveforms in the umbilical artery. METHODS: Criteria for admission into this retrospective study included: singleton pregnancy with a birth weight < 10th centile; absence of severe maternal complications; no evidence of fetal anomalies on the sonogram; normal umbilical artery Doppler; and availability of complete follow-up. At the first antenatal sonogram classifying the fetus as SGA, Doppler analysis of the uterine and middle cerebral arteries was performed and amniotic fluid volume was assessed. Outcome variables included adverse perinatal outcome (perinatal death, severe morbidity) and emergency Cesarean section for fetal distress. RESULTS: Two hundred and thirty-one pregnancies were included in the study. The mean +/- standard deviation birth weight and gestational age at delivery were 2222 +/- 502 g and 37.3 +/- 2.9 weeks, respectively. In 37 cases (16%), an emergency Cesarean section was performed. There was one intrauterine death and three fetuses delivered by emergency Cesarean section developed severe morbidity. Logistic regression demonstrated that abnormal velocimetry of the uterine arteries and fetal middle cerebral artery were independently correlated with the occurrence of Cesarean section. CONCLUSIONS: SGA fetuses with normal umbilical artery Doppler waveforms and abnormal uterine arteries and fetal middle cerebral artery waveforms have an increased risk of developing distress and being delivered by emergency Cesarean section. Particularly when both uterine and fetal cerebral waveforms are altered at the same time, the risk is exceedingly high (86%) and delivery as soon as fetal maturity is achieved seems advisable. On the other hand, when both vessels have normal waveforms, the chances of fetal distress are small (4%) and expectant management is the most reasonable choice.     

植物状态,闭锁综合征和脑死亡的经颅多普勒超声检查

目的：比较植物状态（ＰＶＳ）、闭锁综合征和脑死亡患者脑血流的特点。方法：用经颅多普勒超声（ＴＣＤ）检测ＰＶＳ、闭锁综合征和脑死亡患者双侧大脑中动脉（ＭＣＡ）和基底动脉（ＢＡ）的血流情况。结果：持续植物状态ＭＣＡ和ＢＡ的平均血流速分别为２９．０ｃｍ／ｓ和２３．３ｃｍ／ｓ，较正常下降４７％和２２．３％。闭锁综合征ＭＣＡ和ＢＡ的平均血流速分别为４８．０ｃｍ／ｓ和１０．３ｃｍ／ｓ，分别较正常下降８．２％和６０．０％。提示ＰＶＳ的血流速减慢以前循环为主，而闭锁综合征的血流速减慢以后循环为主。脑死亡则为特殊的双向血流、收缩期短小尖波或无血流信号，与ＰＶＳ或闭锁综合征患者的ＴＣＤ完全不同。结论：根据前后循环血流速减慢的不同及特殊的脑血流频谱，ＴＣＤ能帮助医师鉴别上述三种临床上有时易混淆的状态     

Increased uterine artery vascular impedance is related to adverse outcome of pregnancy but is present in only one-third of late third-trimester pre-eclamptic women.

OBJECTIVE: Signs of increased uterine artery vascular impedance in mid-gestation are strongly related to pre-eclampsia later in pregnancy. Whether this is true for the late third trimester is, however, unclear. The aim of the present study was to analyze the frequency of increased uterine artery vascular impedance in the third trimester, and its relationship to abnormal umbilical artery Doppler and adverse outcome of pregnancy. METHODS: This was a retrospective study of uterine and umbilical artery Doppler velocimetry in 570 pregnancies complicated by pre-eclampsia. The managing clinician was informed only about the umbilical artery flow. The Doppler recordings were related to severity of pre-eclampsia, prematurity, fetal growth restriction, and rates of Cesarean section and admission to neonatal intensive care. RESULTS: Increased umbilical artery vascular impedance was seen in 59 cases (10.4%), seven having absent or reversed end-diastolic flow. Uterine artery notching was seen in 145 cases (25%), 88 (15%) having bilateral notches. Either increased uterine artery pulsatility index (PI) or notching, or both, were seen in 207 women (36.3%). In 108 women with severe pre-eclampsia, 38 (35.2%) had uterine artery notching. Signs of increased uteroplacental vascular impedance were more common in severe than in mild pre-eclampsia (57.4% vs. 31.4%), in premature than in term pregnancies (70.9% vs. 28.4%), and were more prevalent than abnormality in the umbilical artery (36.3% vs. 10.4%). CONCLUSION: Only one-third of pre-eclamptic cases showed signs of increased uterine artery vascular impedance in the third trimester. However, signs of increased vascular impedance were much more frequent in the uterine than in the umbilical arteries and were strongly related to adverse outcome of pregnancy.     

Fetal middle cerebral to uterine artery pulsatility index ratios in normal and pre-eclamptic pregnancies.

OBJECTIVES: To calculate the normal range for the fetal middle cerebral artery (MCA)/uterine artery pulsatility index (PI) ratio in the third trimester of pregnancy and to assess its value, compared with that of the MCA/umbilical artery PI ratio, in predicting an unfavorable outcome of pregnancies complicated by pre-eclampsia. METHODS: Doppler blood flow velocimetry of the uterine and umbilical arteries and fetal MCA was performed. We calculated the ratios between 1) the PI of the MCA and the mean PI value of both uterine arteries and 2) the PI of the MCA and the PI of the umbilical artery. All women were examined at or beyond 26 weeks of gestation. A cross-sectional study of 231 normal pregnancies was conducted to construct the reference range. Values below the 5th percentile or an MCA/umbilical artery PI ratio lower than 1.08 were defined as brain-sparing. A further 115 pregnancies with pre-eclampsia (50 mild and 65 severe) were assessed prospectively and the results were related to perinatal outcome. The accuracy of MCA/uterine artery and MCA/umbilical artery PI ratios for prediction of unfavorable pregnancy outcome was compared. RESULTS: Normal MCA/uterine artery PI ratios decreased with advancing gestational age. Redistribution of the fetal circulation indicated by a low MCA/uterine artery PI ratio was seen in 30% of the mild (n=15) and 46% of the severe (n=30) pre-eclamptic cases. There was a significant difference between those without and those with signs of brain-sparing, respectively, in mean birth weight (2456.0 vs. 1424.5 g), gestational age at delivery (35.6 vs. 31.3 weeks) and gestational age at the time of examination (34.9 vs. 30.9 weeks). Furthermore, there was a significantly higher rate of small-for-gestational-age (SGA) neonates (57.8% vs. 25.7%), preterm delivery (100% vs. 81.8%) and Cesarean section (90.7% vs. 66.7%) in cases with an MCA/uterine artery PI ratio below the 5th percentile. However, there was no difference between the groups in the rate of low 5-min Apgar scores, admission to the neonatal intensive care unit, or deliveries before 34 weeks. The MCA/uterine artery and MCA/umbilical artery PI ratios were similar in the prediction of adverse perinatal outcome. Both ratios were better at predicting the outcome of pregnancy than were signs of increased vascular impedance in either the umbilical or uterine arteries. CONCLUSIONS: Normal MCA/uterine artery PI ratio decreases with gestational age. Abnormally low MCA/ uterine artery PI ratios are related to unfavorable pregnancy outcome. The predictive value of the MCA/uterine artery PI ratio is similar to that of the MCA/umbilical artery PI ratio.     

Cerebral blood flow and CO2 reactivity in interictal migraineurs: a transcranial Doppler study

There is still some controversy about alterations in velocity of blood flow and in cerebral vasomotor reactivity of intracranial arteries in migraineurs during the interictal phase. By means of simultaneous bilateral transcranial Doppler ultrasonography we, therefore, assessed intracranial blood flow velocities and cerebrovascular reactivity to carbon dioxide of all three basal brain arteries in 20 migraineurs during the interictal phase and 30 nonheadache-prone control subjects. Mean blood flow velocities were higher in migraineurs than in controls in all three arteries on both sides, with a significant difference (P < 0.05) for the right anterior cerebral artery and middle cerebral artery under basal conditions and for the right posterior cerebral artery during hypercapnia. Similarly, the cerebrovascular reactivity to carbon dioxide was always higher in patients than in controls, with a significant difference for the left anterior and the right middle cerebral arteries (P < 0.05) and the right posterior cerebral artery (P < 0.01). The broad overlap of cerebrovascular blood flow velocities and CO2 reactivities in patients and controls precluded identification of values diagnostic of migraine. Nevertheless, transcranial Doppler ultrasonography offers the opportunity to noninvasively monitor cerebral blood flow parameters and, therefore, represents a valuable tool for vascular research in migraine.     

Comparison of power Doppler and velocimetry in predicting outcome of high-risk pregnancy.

OBJECTIVE: Prospectively evaluate semi-quantitative computer analysis of power Doppler (PD) signals in the placenta, tetal brain, lung, liver, kidney and spleen in high-risk pregnancies in relationship to perinatal outcome and also to compare tissue blood flow in the fetal brain and placenta with Doppler velocimetry. METHODS: PD signals were recorded in 180 high-risk pregnancies between 27 and 41 weeks of gestation. Images from PD angiographic scans were transmitted for computer analysis of pixel intensity. Mean flow signal intensity was recorded for each organ. The PD brain/lung ratio was calculated. The PD results were plotted on reference values and related to perinatal outcome. Middle cerebral (MCA), umbilical (UA) and uterine artery (Ut. A) velocimetry was also performed. RESULTS: High-risk pregnancies displayed lower PD signal intensity from the placenta, fetal lung, liver and kidney as compared to normals. However, the brain and spleen signals showed higher intensities suggesting increased tissue perfusion. PD signals from the fetal brain, lung, placenta and PD brain/lung ratio were correlated with perinatal outcome. The PD signal intensity from the fetal liver, kidney and spleen showed poor correlation with perinatal outcome. Fetal brain tissue blood flow showed better correlation with the outcome than MCA velocimetry. Placental tissue blood flow results were similar in predicting outcome to those obtained by means of UA and Ut. A velocimetry. CONCLUSION: In comparison with conventional Doppler velocimetry, computer analysis of PD signals, give similar results in the prediction of adverse perinatal outcome.     

Does the measurement of four fetal arteries provide more information than the measurement of just two arteries in prenatal Doppler sonography?

OBJECTIVE: The objective of this study was to evaluate whether the measurement of two or more fetal arteries provides more information and leads to a selection of fetuses at higher risk. DESIGN: In 244 pregnancies Doppler examinations in four fetal arteries (fetal aorta, common carotid artery, middle cerebral artery, umbilical artery) were performed. The evaluation of the results was made by means of a Doppler score for standardization and systematization. The results were divided into four groups (normal, pre-pathological, pathological, highly pathological) and the individual correlations with fetal outcome parameters were investigated. The results from measuring only two fetal arteries (the fetal aorta and middle cerebral artery) were then compared with those from all four arteries. RESULTS: Increasing pathology of the Doppler score correlated with fetal outcome parameters. The results showed that if the Doppler result in the two-vessel measurement was normal (n = 180), pre-pathological (n = 29) or highly pathological (n = 12) then measuring four vessels generally brought no additional information. However, the four-vessel measurement was of advantage in the pathological group (n = 23) because it selected the high-risk fetuses (30.4%), as categorized by outcome. CONCLUSIONS: Differentiating between several degrees of pathology is important for the estimation of fetal risk. In cases of pathological Doppler findings, the measurement of more than two vessels is important in order to select fetuses at increased risk.     

心肌做功指数在评价帆状胎盘孕妇胎儿心功能中的应用

目的应用心肌做功指数（MPI）评价帆状胎盘孕妇胎儿心功能的变化及与不良妊娠结局的关系。 方法选取2016年1月至2018年12月在北京妇产医院确诊帆状胎盘孕妇70例（帆状胎盘组），孕周28~40周，同时选取同孕周正常孕妇89例（对照组），采用t检验比较两组左心室MPI、二三尖瓣口血流速度（E/A比值）及脐动脉搏动指数（UA-PI）、大脑中动脉搏动指数（MCA-PI）和静脉导管搏动指数（DV-PI）。采用ROC曲线分析MPI预测不良妊娠结局，将不良妊娠结局定为如下任意一个：胎儿窘迫、新生儿转ICU、新生儿窒息、呼吸性酸中毒。 结果帆状胎盘组左心室MPI显著高于正常组，差异有统计学意义（t=4.593，P<0.001）；帆状胎盘组UA-PI显著高于正常组，差异有统计学意义（t=-4.142，P<0.05）；帆状胎盘组二尖瓣E/A值、三尖瓣E/A值、MCA-PI、DV-PI与正常组比较，差异均无统计学意义（P均>0.05）。ROC曲线分析显示帆状胎盘组胎儿左心室MPI预测不良结局的ROC曲线下的面积为0.690（95%置信区间为0.580~0.799）。最佳截断值为0.45，其敏感度为83.3%，特异度为38.1%。 结论帆状胎盘孕妇胎儿心功能是降低的，左心室MPI升高在一定程度上与不良妊娠结局显著性相关，从而为监测宫内胎儿安危及改善妊娠结局提供依据。     

Fetal cerebral venous Doppler velocimetry in normal and high-risk pregnancy.

OBJECTIVE: In previous pilot studies, fetal vein of Galen (GV) blood velocity has been shown to be non-pulsatile in normal pregnancies. A pulsating pattern in high-risk pregnancies has been related to adverse outcome of pregnancy. The aim of this study was to establish reference ranges for fetal cerebral venous blood flow and compare them to the recordings in high-risk pregnancies in terms of predicting adverse perinatal outcome. METHODS: The GV, straight sinus (SS) and transverse sinus (TS) were located by color Doppler ultrasound in 189 normal pregnancies between 23 and 43 weeks of gestation. Recordings were also made in 102 pregnancies complicated by pregnancy-induced hypertension and/or intrauterine growth restriction. The following parameters were measured: peak systolic velocity, minimum diastolic velocity, time-averaged maximum velocity, pulsatility index for veins (PIV) and preload index (PLI). GV pulsations were noted. In high-risk pregnancies, Doppler measurements were correlated to pregnancy outcome, including emergency operative intervention and/or neonatal distress. Umbilical vein and umbilical, uterine and middle cerebral artery blood velocities were also recorded at the same time. RESULTS: In normal pregnancy, pulsating venous blood velocity was observed in GV in 8% of cases, in SS in 79% of cases and in TS in 100% of cases. GV and SS maximum velocity increased with gestational age and TS-PIV showed linear decreasing values and TS-PLI showed increasing values with gestational age. In high-risk pregnancies, pulsating blood velocity in the GV was found in 59 (58%) cases and was related to adverse outcome of pregnancy including mortality. Abnormal values for TS-PIV and PLI and SS maximum velocity were found in nine, six and five cases, respectively and were only related to perinatal mortality. GV pulsations were more frequent than umbilical venous pulsations. CONCLUSIONS: Of the fetal cerebral veins studied, the presence of pulsations in the GV seems to be the best predictor of adverse outcome of high-risk pregnancy. Pulsations in the GV are more frequent than in the umbilical vein and might therefore appear earlier during worsening fetal condition, and thus be of potential value for fetal surveillance in high-risk pregnancies.     

Cerebroplacental Doppler ratio and adverse perinatal outcomes in intrauterine growth restriction: evaluating the impact of using gestational age-specific reference values.

OBJECTIVE: The purpose of this study was to compare the impact of using gestational age-specific reference levels of the cerebroplacental Doppler ratio (CPR) with categorical threshold in the prediction of adverse perinatal outcomes in growth-restricted pregnancies. METHODS: A retrospective cohort study of cases of intrauterine growth restriction over a 3-year period was conducted. The umbilical artery and middle cerebral artery pulsatility indices were converted to CPRs. The efficacy of using gestational age-specific reference levels of CPRs in predicting adverse outcomes was compared with the use of a CPR of less than 1.08. Adverse perinatal outcomes evaluated included cesarean delivery for nonreassuring fetal heart tones, umbilical artery pH less than 7.0, 5-minute Apgar scores less than 7.0, intraventricular hemorrhage greater than grade 2, periventricular leukomalacia, respiratory distress syndrome, and perinatal death. RESULTS: Of 183 pregnancies meeting our inclusion criteria, there were 70 with at least 1 adverse outcome. With the use of a CPR ratio below the 5th percentile for gestational age, the sensitivity, specificity, and positive and negative predictive values for predicting an adverse outcome were 65%, 73%, 73%, and 65%, respectively, with an odds ratio (95% confidence interval) of 5.2 (1.4-19.4; area under the receiver operating characteristic curve, 0.69). With a CPR threshold of less than 1.08, the sensitivity, specificity, and positive and negative predictive values were 72%, 62%, 68%, and 67%, with an odds ratio (95% confidence interval) of 4.2 (1.2-15.3; area under the receiver operating characteristic curve, 0.67). CONCLUSIONS: An abnormal CPR is associated with adverse perinatal outcomes in growth-restricted fetuses. The accuracy of using gestational age-specific reference levels was similar to that of using a categorical threshold.     

Qualitative venous Doppler flow waveform analysis in preterm intrauterine growth-restricted fetuses with ARED flow in the umbilical artery--correlation with short-term outcome.

OBJECTIVE: The aim of this retrospective study was to examine the significance of severe Doppler waveform abnormalities in the ductus venosus (DV) and the umbilical vein (UV) for the prediction of adverse outcomes in very preterm growth-restricted fetuses with absent or reversed end-diastolic flow in the umbilical artery (UA) at 24-34 weeks of gestation. METHODS: Seventy-four fetuses with intrauterine growth restriction (IUGR) and absent or reversed end-diastolic (ARED) flow in the UA at 24-34 weeks of gestation, which were delivered before 34 weeks' gestation, were examined. Absent or reversed flow during atrial contraction (a-wave) in the DV and pulsatile flow in the UV were examined to predict severe perinatal outcomes (stillbirth, neonatal death, perinatal death, acidemia, 5 min Apgar < 7, intraventricular hemorrhage and elevated nucleated red blood cell counts at delivery). RESULTS: Twelve (16.2%) perinatal deaths, of which eight were stillbirths (10.8%), and two (2.7%) neonatal deaths occurred among 74 fetuses. Logistic regression analysis confirmed that abnormal DV Doppler waveforms (R2 = 0.57, P < 0.001) together with gestational age at delivery (R2 = 0.57, P < 0.001) showed the strongest association with perinatal death, whereas only gestational age was significantly related to neonatal death (R2 = 0.67, P < 0.05). Abnormal DV Doppler waveforms (R2 = 0.86, P < 0.001) and gestational age (R2 = 0.49, P < 0.05) were strongly associated with adverse outcome (including stillbirth, perinatal death or neonatal death). Abnormal venous Doppler flow patterns performed better in the prediction of fetal or perinatal demise than did ARED flow or brain sparing. CONCLUSION: Abnormal venous Doppler waveforms in preterm IUGR fetuses with ARED flow are strongly related to adverse fetal and perinatal outcomes before 32 weeks of gestation. The possible benefit of prolonging these pregnancies can only be evaluated in a prospective randomized study.     

Fetal adrenal artery velocimetry measurements in appropriate-for-gestational age and intrauterine growth-restricted fetuses.

OBJECTIVE: To investigate adrenal artery blood flow in the fetus. DESIGN AND METHOD: Sixty-two appropriate-for-gestational-age (AGA) and 20 intrauterine growth-restricted (IUGR) fetuses were recruited to this cross-sectional study between 22 and 42 weeks of pregnancy in a tertiary referral fetal medicine unit of a university hospital. ENDPOINTS: Doppler velocimetry of the fetal adrenal, umbilical (UA), renal and middle cerebral arteries (MCA). Pulsatility index (PI), resistance index (RI), peak systolic velocity (PSV), time-averaged maximum velocity (TAMXV) and cerebroplacental ratio (MCA RI/UA RI; CPR). Obstetric outcome. RESULTS: The adrenal artery was detected in 82% of the fetuses. All flow velocity waveforms obtained from the adrenal artery indicated low impedance blood flow. No significant changes in PI, RI, PSV and TAMXV occurred with advancing gestation. The blood flow parameters of the adrenal artery did not differ between AGA and IUGR fetuses. In five IUGR fetuses with signs of redistribution of cardiac output in favor of the brain, the adrenal artery velocimetry results were unremarkable. The adrenal artery PI, RI, PSV and TAMXV values were higher in female fetuses than in male fetuses (P < 0.05). A relationship was observed between the velocity measurements and the estimated fetal weight (P < 0.01). CONCLUSIONS: The fetal adrenal artery could be readily detected. We observed no redistribution of blood flow in favor of the fetal adrenals in IUGR fetuses which were not severely compromised.     

缺血性脑血管病患者脑动脉狭窄特点及相关危险因素分析

目的:分析脑动脉狭窄的分布特点,探讨相关危险因素对脑动脉狭窄的影响.方法:对98例缺血性脑血管病患者行主动脉弓及全脑血管造影,回顾性分析脑动脉狭窄特点及相关危险因素的影响.结果:98例患者中,70例存在脑动脉狭窄或闭塞,颅外段者20例(28.5%),颅内段者32例(45.7%),颅内、颅外均受累者18例(25.7%),...     

扰相梯度双回波序列与3D-TOF-MRA及SWI在显示正常颅内主要动、静脉的比较

目的探讨磁共振扰相梯度双回波序列（dual-echo sequence）同时获得动脉成像及静脉成像的能力。方法选取11例健康志愿者行双回波序列、3D-TOF-MRA及SWI序列检查。将双回波序列所获得的动脉成像对大脑前、中、后动脉各段显示效果与3D-TOF-MRA成像效果比较;同时所获得的静脉成像对脑深部静脉的显示效果与SWI成像效果比较。结果双回波与3D-TOFMRA序列对双侧大脑前动脉A1～A4段、大脑中动脉M1～M2段、大脑后动脉P1～P3段显示效果无明显差异（P〉0．05）。两成像方法对双侧大脑前动脉A5段、大脑中动脉M3段、M4段、M5段及大脑后动脉P4段显示效果具有明显统计学差异（P〈0．05）,31）-TOFMRA序列对以上动脉段的显示效果优于双回波序列。双回波序列与SWI序列对大脑大静脉、双侧大脑内静脉、双侧透明隔静脉、双侧丘纹上静脉的显示效果无明显差异（P〉0．05）。而两成像序列对双侧脉络膜静脉的显示效果具有明显统计学差异（P〈0．01）,SWI序列对其显示效果优于双回波序列。结论双回波序列适合于检出多数大脑内动、静脉,但对小的动脉远端检查以常规31）一TOF—MRA为好;双回波序列亦适合检出多数脑深部静脉,但对于微小静脉的检出以常规SWI更好。     

健康国人年龄性别对主要脑底动脉血流速度的影响及其检测方法的探讨

应用多普勒技术探测颅外脑血管血流速度,1965年由Miyazaki等首先报告,然而,由于骨骼严重衰减超声波,故使用5～10MHz探测频率难以记录颅内血管的血流速度。1982年Aaslid报告了应用脉冲多普勒技术,通过调整取样深度,观察了颅内脑动脉的血流速度,此后,颅内主要脑底动脉的血液动力学变化,以及无创手段对频内脑血管血流速度的监测得到了广泛的研究和深入的开展。我们心功能科自1988年12月引进美国Meda Sonics经颅超声多普勒(TCD)诊断仪以来     

牵引按摩改善颈源性头痛脑血管机能障碍

目的：探讨牵引按摩对颈源性头痛（CH）患者脑血管机能障碍改善的机理。方法：用经颅多谱勒超声（TCD）检测125例有颈椎曲度异常或颈椎退行性改变的颈源性头痛患者牵引按摩前后与正常对照组90例的9条颅内血管（双侧大脑前、中、后动脉、椎动脉及基底动脉），并对TCD结果做统计学分析。结果：1．颈源性头痛组（125例）牵引按摩治疗后，大脑中、前动脉的平均血流速度（Vm），较治疗前降低，其值更接近于正常对照组（P〈0．05或P〈0．01）。2．治疗后颅内成对动脉的Vm差异缩小，其代表值-非对称指数（AI）的异常率以及均值显著低于治疗前，与正常对照组更接近（P〈0．01）。结论：牵引按摩治疗可双向调整颅内动脉的异常血流速度增高和减低，从而改善颈源性头痛患者的脑血管机能紊乱。     

Transcranial colour coded sonography as an aid to measurement of blood flow velocity in the basal cerebral arteries

Unlike conventional transcranial Doppler, transcranial colour coded sonography allows imaging of the basal cerebral arteries. We used this technique to determine blood flow velocities, with compensation for the angle of insonation, in the anterior and posterior cerebral circulation of 60 volunteers categorised by age (20–39, 40–59, > 60 years). Successful vessel insonation declined with increasing age: 40/40 middle cerebral arteries insonated 20–39 y, 31/40 insonated >60 y. Peak, mean and end diastolic blood flow velocities also decreased with age in all arteries: 20–39 y middle cerebral artery mean VELOCITY = 72 cm/s; > 60 y middle cerebral artery mean blood flow VELOCITY = 58 cm/s; p < 0.0001. The pulsatility index increased significantly with age in the middle, posterior cerebral (P2 segment) and vertebral arteries (p < 0.05-0.005), however the resistance index increased significantly with age in all vessels (p < 0.05-0.0001).     

Transcranial measurement of blood velocities in the basal cerebral arteries using pulsed Doppler ultrasound: a method of assessing the Circle of Willis

Transcranial pulsed Doppler ultrasound and spectral analysis were used for detection of blood velocities in the basal cerebral arteries. The Doppler transducer was placed superior to the zygomatic arch and during insonation of the middle cerebral artery care was taken to obtain maximum Doppler-shift frequency signals since this allowed a small angle between the ultrasound beam and this artery. Doppler signals were obtained from the middle, anterior, and posterior cerebral arteries in 20 volunteers with the average depth of the Doppler gate at 4.9 (4.6-5.2 cm), 5.2 (4.9-5.4 cm), and 6.3 cm (6.0-6.9 cm), respectively. These measurements were in agreement with those obtained for 15 cadaver studies, in whom the distance from the proposed site of the Doppler transducer to each basal cerebral artery was measured as 4.7 +/- 0.6, 5.3 +/- 0.5, and 5.9 +/- 0.9 cm, respectively. The reproducibility of middle cerebral artery blood velocity values was tested in seven subjects and showed a variation of not more than 8% in any individual. The method was used in combination with common carotid compression to assess four patients who had occlusive extracranial carotid disease; in three the disease was more severe on one side and reversal of blood flow in the proximal ipsilateral anterior cerebral artery was demonstrated, consistent with cross flow from the contralateral side via the anterior communicating artery of the Circle of Willis. In the fourth patient augmentation of posterior cerebral artery blood velocities during common carotid compression indicated the major collateral source was from the vertebrobasilar system.     

多普勒频谱分析胎儿宫内缺氧

目的综合分析子宫动脉、脐动脉及大脑中动脉多普勒指标(PI值)变化关系对评价胎儿缺氧的意义。方法运用多普勒技术检测90例因不良妊娠住院患者子宫动脉、胎儿脐动脉及大脑中动脉搏动指数(PI),回顾分析妊娠结局与各频谱参数变化的关系。结果子宫动脉异常(PI≥95th)伴脐动脉参数升高(PI>50th)和(或)大脑中动脉参数降低(PI<50th)者妊娠结局不良,且脐动脉参数升高至异常时(PI≥95th)围产儿病死率增高;子宫动脉正常时(PI<95th),脐动脉参数异常(PI≥95th)伴大脑中动脉参数降低者(PI<50th)妊娠结局不良;大脑中动脉血流参数异常者(PI≤5th)妊娠结局不良;单一子宫动脉或脐动脉血流参数异常者(PI≥95th)妊娠结局良好。结论综合分析子宫动脉、脐动脉及大脑中动脉频谱指标变化关系,可判定及评估胎儿缺氧情况、提示预后。