腔隙性脑梗死小动脉病变的血流动力学特点研究

【目的】探讨腔隙性脑梗死中小动脉病变的脑血流动力学特点。【方法】采用经颅多普勒(TCD)观察85例排除伴有明显大血管病变的腔隙性脑梗死患者脑内主要动脉的血流动力学改变,并与年龄和动脉血压等指标进行相关性分析。并设立相同年龄段的头颅影像检查正常的25例健康体检者作为对照。【结果】腔隙性脑梗死组大脑中、前、后动脉的平均血流速度分别为(62.09±16.90)cm.s-1、(50.42±13.11)cm.s-1、(32.33±7.55)cm.s-1,均低于对照组的(69.65±19.20)cm.s-1、(57.75±16.75)cm.s-1、(38.75±8.81)cm.s-1(均P<0.05),脉动指数分别为1.05±0.26、1.01±0.24、1.05±0.23,均高于对照组的0.87±0.12、0.88±0.20、0.88±0.16(均P<0.05)。其中大脑中、前、后动脉的平均血流速度与性别、年龄和动脉血压无明显相关性,而脉动指数与年龄呈正相关(r分别为0.394、0.299、0.352,均P<0.05),大脑前动脉的脉动指数与收缩压和脉压差呈正相关(r分别为0.338、0.353,P<0.05),大脑中动脉的脉动指数与脉压差呈正相关(r=0.220,P<0.05),梗死灶所在的患侧和没有梗死灶的健侧的血流速度和脉动指数均未见显著性差异(P>0.05)。【结论】腔隙性脑梗死患者小动脉病变可导致血流速度轻度减慢,脉动指数升高,其中脉动指数与年龄和动脉血压有一定相关性。     

肾虚肝郁型LUFS卵巢动脉血流动力学特点及罗氏调经种子丸的调节作用

【目的】分析肾虚肝郁型黄素化未破裂卵泡综合症(LUFS)患者卵巢动脉的血流动力学特点及罗氏调经种子丸的调节作用。【方法】应用阴道彩色多普勒超声检测30例有正常排卵周期的健康妇女(正常组)和20例肾虚肝郁型LUFS患者(LUFS组)治疗前后排卵期和黄体各期排卵侧卵巢动脉的阻力指数(RI)和搏动指数(PI)。【结果】正常妇女卵泡期和黄体各期卵巢动脉RI和PI呈规律性变化:卵泡期的RI和PI较黄体各期均显著性增高,卵巢动脉在卵泡期呈高阻力状态,卵巢动脉RI、PI从黄体早期开始降低,在黄体中期达最小值,到黄体晚期则开始明显回升。肾虚肝郁型LUFS患者治疗前月经各期排卵侧卵巢动脉始终保持高阻力状态,卵泡期和黄体各期RI、PI相接近,即RI、PI从卵泡期到黄体中期均无明显改变,失去原有周期性变化规律。治疗后患者月经各期排卵侧卵巢动脉RI、PI按卵泡期、黄体早期、黄体中期顺序依次呈显著性降低,到黄体晚期又开始回升(黄体各期与治疗前比较,P<0.05或P<0.01),基本恢复了正常妇女排卵侧卵巢动脉RI和PI的规律性变化(各期与正常组比较,均P>0.05)。【结论】罗氏调经种子丸能有效调节LUFS患者卵巢动脉的血流灌注,恢复月经周期正常的变化规律。     

Maternal glycemic control and umbilical artery Doppler velocimetry

Objective: To determine whether information from umbilical artery Doppler flow velocity waveforms significantly improves the prediction of adverse perinatal outcome, independently of maternal glycemic control, in pregnancies complicated by diabetes. Study design: The medical records of 277 pregnant women with diabetes were reviewed. Glycemic control was determined by glycosylated hemoglobin concentration and umbilical artery Doppler velocimetry by using systolic/diastolic ratios (S : D), both obtained during the third trimester. Pregnancies with adverse perinatal outcome were compared to those with good outcome. Logistic regression analysis was used to adjust for glycemic control, and to test whether an elevated umbilical artery Doppler S : D ratio was independently associated with pregnancy outcome. Results: Adverse pregnancy outcome occurred in 51.6% of these pregnancies (143/277). The mean third-trimester glycosylated hemoglobin (7.7 ± 1.9% vs. 6.7 ± 1.3%, p < 0.001) and the umbilical artery S : D ratio were significantly higher (2.6 ± 0.6 vs. 2.4 ± 0.3, p < 0.001) in the pregnancies with adverse outcome. Logistic regression analysis showed that umbilical artery S : D ratio was an independent predictor of adverse perinatal outcome after adjusting for the third-trimester glycosylated hemoglobin level. Forty per cent of patients with normal Doppler findings (S : D ratio of < 3.0) and normal glycemic control values (glycosylated hemoglobin level of < 7.5%) had an adverse pregnancy outcome. Sixty-three per cent of patients with an abnormal result for one of these tests had an adverse pregnancy outcome. Ninety-six per cent of patients with both abnormal Doppler findings and abnormal glycemic control had an adverse pregnancy outcome. Conclusion: Umbilical artery Doppler velocimetry improves the predictive value for adverse perinatal outcome, independently of glycemic control, in pregnancies complicated by diabetes. The combination of an abnormal umbilical artery S : D ratio and abnormal glycosylated hemoglobin was strongly associated with adverse pregnancy outcome.     

Doppler ultrasonography screening of poor-grade subarachnoid hemorrhage patients increases the diagnosis of deep venous thrombosis

Abstract

Background: Prophylactic anticoagulation greatly decreases the prevalence of deep venous thrombosis (DVT) in neurosurgical patients. Using Doppler ultrasonography (USG), recent studies demonstrate a 1% DVT detection rate following microsurgery or endovascular treatment for aneurysmal subarachnoid hemorrhage (aSAH). We hypothesize that reported statistics underestimate the DVT detection rate in this high risk cohort by accounting for only symptomatic thromboses. This study utilizes Doppler USG to examine the prevalence of DVT in a large population of aSAH patients and attempts to identify a high-risk subgroup within this cohort.

Methods: We retrospectively examined 178 aSAH patients who underwent screening lower extremity Dopplers (LEDs) and 57 who did not undergo screening LEDs. All received pharmacologic and mechanical DVT prophylaxis. We analysed DVT prevalence within these two groups and compared rates to the literature. We then segregated patients according to Hunt–Hess grade and determined DVT prevalence within subgroups.

Results: Patients who underwent LED screening demonstrated a 3.4% (6/178) DVT rate, compared to 0% (0/57) in the unscreened cohort. Our screening protocol yielded a thrombosis rate almost triple that reported in the literature (3.4% versus 1.2%). A significantly greater (p<0.05) percentage of screened Hunt–Hess III–V patients (6.5%, 6/93) had positive LEDs compared to Hunt–Hess I–II patients (0%, 0/85).

Conclusion: These data suggest that while pharmacologic prophylaxis lowers the prevalence of symptomatic DVTs in aSAH patients, the number of asymptomatic DVTs remains significant, particularly in patients with formidable neurological deficits. While a formal cost-effective analysis is warranted, our data suggest that screening high-risk patients may increase the diagnosis of asymptomatic DVTs and potentially prevent serious medical complications.     

Second-trimester uterine artery Doppler screening in unselected populations: a review

Objective: Doppler ultrasound provides a non-invasive method for the study of the uteroplacental circulation. In normal pregnancy, impedance to flow in the uterine arteries decreases with gestation, which may be the consequence of trophoblastic invasion of the spiral arteries and their conversion into low-resistance vessels. Pre-eclampsia and fetal growth restriction are associated with failure of trophoblastic invasion of spiral arteries, and Doppler studies, in these conditions, have shown that impedance to flow in the uterine arteries is increased. A series of screening studies involving assessment of impedance to flow in the uterine arteries have examined the potential value of Doppler in identifying pregnancies at risk of the complications of impaired placentation. This review examines the findings of Doppler studies in unselected populations. Methods: Searches of a computerized medical database were performed to identify relevant studies. Only those studies that provided sufficient data to allow calculation of the performance of the test were included in the analysis. Likelihood ratios were calculated for each study and are reported for pre-eclampsia, fetal growth restriction and perinatal death as well as for more severe forms of pre-eclampsia and fetal growth restriction. Results: The literature search identified 19 relevant studies, four of which were excluded from the further analysis. The main characteristics and results of the 15 remaining studies provided discrepant results, which may be the consequence of differences in Doppler technique for sampling, the definition of abnormal flow velocity waveform, differences in the populations examined, the gestational age at which women were studied and different criteria for the diagnosis of pre-eclampsia and fetal growth restriction. Nevertheless, the studies provided evidence that increased impedance to flow in the uterine arteries is associated with increased risk for subsequent development of pre-eclampsia, fetal growth restriction and perinatal death. In addition, women with normal impedance to flow in the uterine arteries constituted a group that have a low risk of developing obstetric complications related to uteroplacental insufficiency. Conclusions: The review suggests that increased impedance to flow in the uterine arteries in pregnancies attending for routine antenatal care identifies about 40% of those who subsequently develop pre-eclampsia and about 20% of those who develop fetal growth restriction. Following a positive test, the likelihood of these complications is increased by about 6 and 3.5 times, respectively.     

Hepatic Blood Flow Changes in Chronic Hepatitis C Measured by Duplex Doppler Color Sonography: Relationship to Histological Features

Our aim was to determine if portal vein andhepatic artery blood flow indices are a noninvasiveindex of severity of liver disease in chronic hepatitisC. The effect of interferon- treatment on liver blood flow was also studied. Liver blood flowmeasurements were recorded by duplex Doppler colorsonography in 39 patients with chronic hepatitis C, 50healthy controls, and a single patient withhepatocellular carcinoma. Doppler perfusion index (DPI)(calculated as the ratio of hepatic artery flow to totalhepatic flow) and the congestive index of the portalvein (area/velocity) were calculated. Liver biopsies were scored for hepatic inflammation andfibrosis. Hepatic arterial flow (415.7 ± 329.1ml/min vs 195.1 ± 103.5 ml/min) and DPI (0.27± 0.14 vs. 0.17 ± 0.06) were elevated inchronic hepatitis C patients compared to controls (P = 0.0002 and0.0003, respectively) while portal vein flow and totalhepatic flow were similar. Portal vein congestive indexwas similar in chronic hepatitis C (0.106 ± 0.05) compared to controls (0.125 ±0.08) P 0.52. Hepatic blood flow indices were notrelated to the grade of hepatic inflammation or thestage of hepatic fibrosis. Twelve weeks of treatmentwith interferon- had no effect on liver blood flow. Inconclusion, patients with chronic hepatitis C haveelevated hepatic artery blood flow. Hepatic blood flowindices have no relationship to the severity ofhistological liver injury in chronic hepatitis C, and theseflow indices are unaffected by a 12-week course ofinterferon-.     

Distribution of artificial cerebral microemboli in stroke patients with patent foramen ovale

Abstract

Objectives: Patent foramen ovale (PFO) is considered as an important risk factor for cerebrovascular diseases. Nevertheless, the relationship between the distribution of highintensity transient signals (HITS), resulting from injection of air mixed with saline and detected by transcranial Doppler (TCD), and clinical cerebrovascular syndromes in these patients has not been investigated.

Methods: Using TCD, we screened 40 patients with stroke or transient ischemic attack (TIA), in whom PFO was proven by transesophageal echocariography (TEE). Of these, 30 patients (75%) with artificially produced HITS either in the middle cerebral artery (MCA) or the basilar artery (BA) were included in the analysis.

Results: Nineteen patients had a stroke or TIA in the carotid territory and 11 patients in the vertebro-basilar territory. HITS were found in the MCA in all 30 patients and in 21 of the 30 patients in the BA. Of the latter, ten patients were in the carotid group and 11 patients were in the veretebro-basilar group, p=0.011.

Conclusion: There is a significant association between the distribution of artificial HITS and the clinical cerebrovascular syndromes.     

Changes in hemodynamics during isoflurane and propofol anesthesia: a comparison study

Abstract

Objectives: Volatile anesthetics are thought to impair cerebral autoregulation more than i.v. anesthetics. However, few comparative studies have been carried out in humans. The aim of our study was to evaluate the differences in cerebral hemodynamic changes after introduction of isoflurane (a volatile anesthetic) and propofol (an i.v. anesthetic).

Methods: Eighteen consecutive patients submitted to laparoscopic cholecystectomy were selected. After the induction, anesthesia was maintained by isoflurane (one minimum alveolar anesthetic concentration) during the first part of the surgical operation, and then by propofol (5 mg/kg/hour i.v.). Ventilation was adjusted to maintain a constant end-tidal CO₂. Middle artery flow velocity was assessed by means of transcranial Doppler ultrasonography. Arterial blood pressure, heart rate (HR), capnometry, pulse oxymetry, inspired fraction of O₂, and body temperature, were monitored.

Results: Cerebral artery velocity, HR, and mean arterial pressure all significantly increased from baseline after the introduction of isoflurane (p<0.05); the HR and mean arterial blood pressure showed no significant difference between the isoflurane and propofol phases. Isoflurane anesthesia induced a significant increase in cerebral blood velocity. Propofol introduction led to a significant decrease in cerebral artery velocity (p<0.05).

Conclusions: Propofol but not isoflurane decreased cerebral blood velocity thus restoring cerebral autoregulation and the coupling between cerebral blood flow and cerebral metabolism.     

高频超声图像结合彩色多普勒血流检查在诊断乳腺肿块中的价值

[目的]探讨乳腺良恶性肿块的高频超声图像和彩色多普勒血流检查(Color Doppler velocimeter,CDV)表现与其相关的病理特征,评估超声检查对乳腺良、恶性肿块的诊断价值。[方法]分析113例乳腺肿块的声像图特征及CDV表现与手术病理结果进行对照研究。[结果]乳腺良、恶性肿块声像图表现与病理改变有一定的关系。CDV检查中乳腺癌血流信号检出率97.80％,阻力指数RI=0.77±0.06;良性肿块检出率61.76％,RI=0.52±0.05,二者差异有显著性(P<0.01)。[结论]二维超声结合CDV诊断乳腺肿块符合率高,具有较高的临床使用价值。     

Doppler ultrasonographic measurement of blood flow velocities in major cerebral arteries of the rat using triplex mode

Abstract

Objective: In patients with subarachnoid hemorrhage, delayed cerebral ischemia caused by vasospasm of major cerebral arteries is an important factor of morbidity. While Doppler ultrasonographic monitoring of blood flow velocities is a routine bedside examination in these patients, the current rodent models of vasospasm do not include this technique. In this article, we present an extended craniectomy in rats, which allows for direct angle-corrected Doppler ultrasonographic examination of major cerebral vessels.

Methods: Ultrasonographic examination employs a triplex window displaying simultaneously B-mode, colour coded vessel rendering and Doppler-assessment of blood flow velocity. The animals receive anesthesia for the measurements, which are repeated several times a week.

Results: Mean flow velocities determined by 116 measurements in 16 animals are (cm/s): truncus cerebri anterius: 8.16, arteria pericallosa: 7.49, arteries (Aa.) cerebri anteriores: 7.76, Aa. carotides: 8.76, Aa. cerebri mediae: 8.55, Aa. cerebri posteriores: 5.27, artery (A.) basilaris: 5.90.

Discussion: We describe the direct intravital detection of blood flow velocities in major cerebral vessels of the rat. The technique allows for simultaneous visualization of intracranial structures, vessel diameters and cerebral blood flow velocities. Our ongoing research focuses on determining normal values in a larger population of animals and examining the feasibility of the technique regarding the rodent model of vasospasm.