多普勒超声心动图评估左心室舒张末压的研究

目的探讨多普勒超声心动图评估左室舒张末压的有效方法与指标。方法对６８例病人采用左心导管测压及经胸多普勒超声心动图检测。结果对比研究显示,联合肺静脉与二尖瓣血流频谱分析优于二尖瓣血流频谱分析,肺静脉Ａ峰和二尖瓣Ａ峰时限差值（ＰＡｄ－Ａｄ）与左室舒张末压实测值呈最佳相关性（ｒ＝０．７２,Ｐ＜０．０１）。结论认为应用多普勒超声心动图测定ＰＡｄ与Ａｄ,并以其差值估测左室舒张末压,是一项简便、可靠的无创性评估左室舒张末压的方法。ＰＡｄ－Ａｄ≥０可作为临床判断左室舒张末压增高［≥２．０ｋＰａ（１５ｍｍＨｇ）］的一项半定量指标。     

Changes in optic nerve head blood flow and retrobular hemodynamics following calcium-channel blocker treatment of normal-tension glaucoma

Background: Because calcium channel blockers reduce vascularresistance, they may have a clinical application in the treatment ofnormal-tension glaucoma (NTG). This study investigates changes inboth the optic disc blood flow and the hemodynamics of retrobulbarvessels in NTG patients after the systemic administration of a calcium channel blocker. Methods: Twelve eyes of 12 NTG patients (meanage 57 6 ± 15.3 years) were examined before and after a 4-weektreatment with 2 mg b.i.d. oral nilvadipine, an L-typc calcium channel blocker. By scanning laser-Doppler flowmetry (SLDF), we obtained the velocity, flow, and volume from within a 10 × 10 pixel windowplaced on the temporal rim region of the optic disc perfusion map. Byultrasound color Doppler imaging (CDI), we measured the peak systolicvelocity (PSV) and the end diastolic velocity (EDV) of the ophthalmicartery (OA), central retinal artery (CRA), nasal posterior ciliary artery (NPCA), and temporal posterior ciliary artery (TPCA). We then calculated a resistance index (RI) for each vessel. Results: After treatment, the flow and velocity of the optic disc blood flow significantly increased (P < 0.05).Nilvadipine also significantly reduced RIs of the CRA, NPCA, and TPCA(P <0 .05), and increased both the PSV of the NPCA and the EDVs of the CRA, NPCA, and TPCA. The percent change in velocity correlated significantly with the percent changes of the CRA RI and NPCA RI. Conclusions: Oral nilvadipine appears to reduce orbital vascular resistance, which consequentlyincreases the optic disc blood flow. Abbreviations.BP – blood pressure;CRA – central retinal artery;CDI – ultrasound color Doppler imaging;EDV – end diastolic velocity;NPCA – short posterior ciliary arteries located nasal to optic nerve;NTG – normal-tension glaucoma;OA – ophthalmic artery;PP – perfusion pressure;PSV – peak systolic velocity;RI – resistance index;SLDF scanning laser-Doppler flowmetry;TPCA – short posterior ciliary arteries locatedtemporal to optic nerve.     

A comparative study on the effects of apraclonidine and timolol on the ophthalmic blood flow velocity waveforms

Purpose: To evaluate the effects of topical timolol and apraclonidine on retrobulbar blood flow velocity waveforms in a group of healthy volunteers.Methods: Apraclonidine 1% and timolol maleate 0.5% single dose administrations were crossed over double masked in 12 healthy volunteers. The intraocular pressure measurements were followed by Doppler examination of the ophthalmic artery and the central retinal artery.Results: Intraocular pressure was reduced significantly on both treated and fellow eyes after timolol (p = 0.003, p = 0.04 respectively) and after apraclonidine (p = 0.002, p = 0.01 respectively). After apraclonidine administration end diastolic velocity, mean velocity decreased and pulsatility index increased in the ophthalmic artery of both treated and fellow eyes. Resistivity index increased and peak systolic velocity decreased only in the ophthalmic artery of treated eyes. All Doppler indices remained nonsignificant for central retinal artery of both eyes.After timolol administration there were no significant changes of the Doppler indices in the ophthalmic artery and central retinal artery of the treated and fellow eyes.Conclusion: Topical timolol and apraclonidine significantly reduced the intraocular pressure. Single dose administration of apraclonidine 1% increased the vascular impedance distal to the ophthalmic artery. On the other hand, timolol 0.5% had no effect on vascular impedance.     

应用彩色多普勒血流显像检测眼前部缺血性视神经病变

应用彩色多普勒血流显像检测眼前部缺血性视神经病变,以探讨其血流动力学变化特征。     

正常眼共焦扫描激光多普勒视网膜血流图

目的　探讨共焦扫描激光多普勒视网膜血流图的临床应用价值。方法　应用Ｈｅｉｄｅｌｂｅｒｇ共焦扫描激光多普勒视网膜血流图仪对４８ 例（８２ 只正常眼）视乳头及视网膜血流灌注进行检测。结果　视乳头大血管血流量为２０３１４ ±７４７７,血流速为６ ２７２４３ ±２ ２６００７ ,红细胞移动速率为１３１４ ±２５８ ;视乳头筛板处的血流量为２６３６ ±１４７４ ,血流速为４６７９９ ±２７０１５ ,红细胞移动速率为１９３ ±１０７ 。颞侧视乳头盘沿的血流量为２２９０ ±１１３２,血流速为５１４５３ ±３７０２１,红细胞移动速率为１６９±１１２ ;鼻侧视乳头盘沿的血流量为２１７７ ±９８３,血流速为４９３２１ ±２９０２９,红细胞移动速率为１６５±０９０;颞侧与鼻侧比较差异无显著性（ｔ 值分别为０６８２ ５ ,０４１０ ４,０２５０ １,Ｐ＞ ００５） 。颞侧视乳头旁视网膜的血流量为３２５５ ±１３００,血流速为５５８６３ ±２９３４５ ,红细胞移动速率为１７８ ±０８３;鼻侧视乳头旁视网膜的血流量为２０６１ ±８９２ ,血流速为３５８６４ ±２１２６６ ,红细胞移动速率为１２     

Microembolization from a carotid mural thrombus detected by transcranial Doppler

Over the last few years, many authors have described the possibility of using transcranial Doppler to demonstrate the passage of microemboli in the cerebral arteries. We report the case of a 44-year-old woman with thrombotic diathesis and thrombocytosis who was admitted twice within a short period of time (one and a half months) to a neurological department because of multiple cerebral infarctions. On the occasion of the second admission, a colour-Doppler examination of the epiaortic vessels, which had previously been negative, showed a carotid lesion due to a mural thrombus and, on the same side as the carotid lesion, transcranial Doppler detected short-duration, high-intensity signals in the middle and anterior cerebral arteries, an expression of the passage of microemboli.As already described by other authors in similar clinical situations, our case confirms that transcranial Doppler can identify the passage of microemboli in the circle of Willis.

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Sommario Negli ultimi anni è stata descritta da molti autori la possibilità di dimostrare mediante Doppler transcranico il passaggio di microemboli nelle arterie cerebrali. Riportiamo il caso di una donna di 44 anni con diatesi trombotica e trombocitosi ricoverata per due volte, a breve distanza di tempo (un mese e mezzo), in ambiente neurologico per infarti cerebrali multipli. In occasione del secondo ricovero l'esame Color-Doppler dei vasi epiaortici, che era risultato negativo in precedenza, ha evidenziato una lesione carotidea riferibile a un trombo murale e al Doppler transcranico sono stati rilevati, omolateralmente alla lesione carotidea, segnali di breve durata ed alta intensità nelle arterie cerebrali media e anteriore, espressione di passaggio di microemboli.Come già descritto da alcuni autori in situazioni cliniche simili, il nostro caso conferma la possibilità di individuare, mediante Doppler transcranico, il passaggio di microemboli nel circolo cerebrale.

     

Doppler flow velocity measurements in patients with intracranial hypertension

Summary In patients with severe brain lesions monitoring of the intracranial pressure as well as monitoring of cerebral blood flow can be of clinical value. While at the moment there is no atraumatic method for measuring cerebral blood flow in man, it is recommended to measure blood flow velocity with the ultrasound Doppler technic in the common carotid artery. On theoretical grounds a positive correlation between cerebral blood flow and blood flow velocity can be expected and the observations presented show that such a correlation exists in normal controls and in neurological patients. In many neurological patients the flow velocity in the common carotid artery decreases with increasing intracranial pressure. This suggests that the autoregulation is disturbed. The demonstration of such a disturbance can have clinical implications.

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Zusammenfassung Bei Patienten mit ernsten Läsionen im Gehirn kann Monitoring von sowohl intercraniellem Druck als auch der zerebralen Blutdurchströmung für die Klinik von Bedeutung sein. Da im Moment keine atraumatische Methode für die Messung der zerebralen Blutdurchströmung besteht, wird anempfohlen, die Durchströmungsgeschwindigkeit mit der Ultraschall-Doppler-Technik in der Arteria carotis communis zu messen. Theoretisch kann eine positive Korrelation zwischen der zerebralen Blutdurchströmung und der Strömungsgeschwindigkeit erwartet werden.Die beschriebenen Ergebnisse zeigen, daß tatsächlich ein solcher Zusammenhang besteht, sowohl bei gesunden Versuchspersonen als auch bei neurologischen Patienten.Bei vielen dieser Patienten nimmt die Durchströmungsgeschwindigkeit in der Arteria carotis communis ab bei einer Zunahme des intracraniellen Druckes. Dies suggeriert eine gestörte Autoregulation. Das Aufzeigen einer solchen Störung kann klinische Bedeutung haben.

     

Systolic arterial pressure determination by a new pulse monitor technique

The Doppler ultrasound (DUS) technique is a widely accepted non-invasive technique to estimate systolic blood pressure (SBP) accurately in paediatric patients. The DUS has a number of limitations. A new pulse monitor, Mr Pulse (MP), operating on the principle of a finger plethysmograph, was developed to offer an alternative technique to estimate SBP. From 104 paired SBP measurements taken in 16 paediatric patients undergoing general anaesthesia, SBP determined by the MP technique correlated closely with that by the standard DUS technique (r2 = 0.98). Analysis of degree of agreement performed indicated that there was good agreement between SBP obtained by the MP and the DUS techniques. The mean +/- standard deviation of differences in paired SBP values between the two measurement techniques was 0.55 +/- 3.59 mmHg. Mr Pulse is as accurate as the DUS technique in estimating SBP and has the advantage of less critical sensor positioning as it is not subject to electrical interference. It has no electrical hazard.     

Measurement of cardiac output-transtracheal Doppler versus thermodilution

The ABCOM 1 transtracheal Doppler (TTD) has been developed as a non-invasive cardiac output monitor. With this device, cardiac output is continuously calculated from ascending aortic blood flow velocity and aortic diameter obtained via an ultrasound transducer incorporated into the tip of an endotracheal tube. We evaluated the clinical use of the ABCOM 1 monitor and compared cardiac outputs obtained using the TTD system with simultaneous thermodilution (TD) measurements. We found the operation of the ABCOM 1 monitor to be difficult and time-consuming. In our operating rooms, acceptable Doppler signal quality was difficult to obtain. There was no correlation between 36 simultaneously obtained TTD and TD cardiac output measurements. The average difference between measurement techniques and the limits of agreement were unacceptably large (mean difference = 3.04 L.min-1, mean +/- 2 SD = -6.04 to 12.48 L.min-1). Separately analyzing only those measurements during which Doppler signal quality was adequate did not improve agreement between TTD and TD measurements. On the basis of these findings, TTD cannot be recommended as a clinical cardiac output measurement technique.     

Echocardiographic and color flow Doppler assessment of systemic and pulmonary venous connection and drainage in the neonate with congenital heart disease

Systemic and pulmonary venous anomalies are frequently encountered either as isolated lesions or as a significant component of a more complex lesion in the newborn infant with congenital heart disease. Two-dimensional echocardiography and Doppler techniques (conventional and color flow) have become the primary diagnostic imaging modality in this setting. Precise pre-operative definition of these variable venous connection and drainage patterns is critical as the required surgical procedure may solely be based on exact understanding of the veins' anatomy and physiology. On the systemic venous site, anomalies of superior and inferior venae cavae, innominate vein, and coronary sinus can be equally well imaged with either echocardiography or angiography. However, on the pulmonary venous site, echocardiography and Doppler techniques including color flow mapping are superior to angiography for precise definition of the connection and drainage sites of the individual pulmonary veins.