Pulsed Doppler Ultrasonography Research Articles

The effect of fetal behavioral states on middle cerebral artery peak systolic velocity

ObjectiveThis study was undertaken to determine whether is there a difference in the middle cerebral artery peak systolic velocity (MCA PSV) between active and resting behavioral states in healthy fetuses aged 30 to 32 weeks. MethodsMCA blood flow was measured by pulsed Doppler sonography 3 times during each fetal behavioral state (active and resting). The average during active state was compared during the resting state. Statistical analysis was performed by paired t test. ResultsDuring the fetal active state, there was a significant increase in the mean PSV (51.59 cm/s vs 46.95 cm/s, P < .0001) and mean end-diastolic velocity (9.59 cm/s vs 7.98 cm/s, P=.0015), and a significant decrease in the mean pulsatility index (PI) (2.07 vs 2.19, P=.0226) and the mean resistance index (0.83 vs 0.85, P=.0481). ConclusionHealthy preterm fetuses have a significantly higher MCA PSV during the active state. Activity state should be considered when interpreting MCA Doppler indices.

Cerebral blood flow velocity before and after cerebrospinal fluid drainage in infants with posthemorrhagic hydrocephalus.

Currently, the timing and volume of cerebrospinal fluid (CSF) drainage are determined by subjective clinical findings in infants with posthemorrhagic hydrocephalus. The aim of this study was to determine whether measurement of the resistive index is useful for management of CSF drainage in these infants. We measured the resistive index in the anterior cerebral artery (RI-ACA) by using pulsed Doppler sonography before and after lumbar or subcutaneous ventricular catheter reservoir punctures in 7 infants with posthemorrhagic hydrocephalus. The increased RI-ACA values (mean +/- SD, 0.86 +/- 0.04; range, 0.80-0.89) decreased significantly (0.76 +/- 0.05; 0.64-0.83) after removal of CSF at a rate of 5 to 10 mL/kg (P <.0001). We suggest that measurement of the RI-ACA may be useful for evaluating the efficacy of CSF drainage and to determine how much CSF should be removed in hydrocephalic infants.

A retrospective multicentre study comparing myomectomy by laparoscopy and laparotomy in current surgical practice: What are the best patient selection criteria?

Objective: To determine the differences in myoma characteristics before laparoscopic myomectomy (LM) and abdominal myomectomy (AM) and to compare outcomes in current practice. Study design: We analysed retrospectively the data for 126 LMs and 176 AMs performed between January 1996 and January 2000 in 11 centres. Myomas were examined by transvaginal B-mode, colour and pulsed energy Doppler ultrasonography. The following data were collated: (i) pre-operative: myoma size, number, type and location and medical treatment, (ii) per-operative: operator, blood loss, surgical procedure and operative time, and (iii) post-operative: myoma weight and number, haemoglobin decrease, complications and length of hospital stay. Results: Compared to women undergoing LM, women undergoing AM had more myomas that were larger and that were generally interstitial and anterior. More of them received GnRH analogues. Excised myomas weighed four times more, the decrease in haemoglobin was greater (1 g/dl), fever was more frequent, and nine patients needed transfusions (compared to none for LM). There were 37 laparoconversions (29%) after LM. The conversion rate was high for inexperienced surgeons. Length of hospital stay was reduced by half for LM (without laparoconversion). Recurrence rate at 2 years was 2.5% for LM versus 3.6% for AM ( P=0.506). Conclusion: Pre-operative evaluation by ultrasound is essential to establish myoma number, size, type and location in order to choose the most appropriate surgical procedure.

Reverse flow in fetal vessels and perinatal events

BACKGROUND/PATIENTS: A reverse flow in the umbilical artery and/or fetal aorta is associated with a higher perinatal and neonatal mortality. 30 fetuses showed a reverse flow using pulsed wave Doppler sonography (group I). A matched-pair control group including 30 fetuses with the same gestational age as well as a normal Doppler flow pattern in the umbilical artery and/or fetal aorta was taken for comparison (group II). In the group with reverse flow the rates of pregnancies with pre-eclampsia (n = 19/30, p < 0.0001), intrauterine growth retardation (n = 25/30, p < 0.0001), oligohydramnios (n = 21/30, p < 0.0001) and nicotine abuse (n = 15/30, p < 0.01) were significantly higher compared to the control group. Postnatal data showed significantly lower pH values in group I (p < 0.01). 40 % of the fetuses with reverse flow died in utero whereas in 67 % the reverse flow was accompanied by an insufficiency of the placenta (IUGR, oligohydramnios, histopathological abnormalities of the placenta). None of the fetuses in the control group died in utero. The incidence of IUGR (< 5ht percentile) was 83 % in group I but only 3 % in group II. The perinatal and overall mortality (including neonatal mortality 7 - 28 days after birth) amounted to 27 % and 53 % in group I, respectively, compared to 3 % and 0 % in the control group (p < 0.001). In addition cerebral anomalies could be found by ultrasound in 50 % of the neonates who presented a reverse flow prenatally. In 28 % of the surviving newborns an intracerebral hemorrhage (ICH) could be detected. None of the newborns of group II developed an ICH. Pregnancies with a reverse flow in the umbilical artery and/or fetal aorta have to be considered as a high risk group with a poor prognosis. The reverse flow is mainly caused by chronic placental insufficiency with IUGR. With respect to the further neuromotor development the incidence and severity of cerebral lesions in affected fetuses should be considered when discussing the perinatal situation with the parents.

Portal and splenic hemodynamics in cirrhotic patients: relationship between esophageal variceal bleeding and the severity of hepatic failure.

The relationship between portal and splenic vein hemodynamics, liver function, and esophageal variceal bleeding in patients with cirrhosis remains unclear. The aim of the present study was to investigate quantitative Doppler parameters of splanchnic hemodynamics in cirrhotic patients and to determine the value of the Doppler parameters in predicting esophageal variceal bleeding. With the help of pulsed Doppler ultrasonography, we investigated portal and splenic hemodynamics in 18 healthy controls and in 45 patients with liver cirrhosis, in whom the relationship of splenic hemodynamics with esophageal variceal bleeding and the grade of cirrhosis was examined. Portal flow velocity was decreased in cirrhotic patients with Child's C cirrhosis, as compared to those with Child's A cirrhosis ( P < 0.001). The portal blood flow volume in Child's C cirrhosis were also significantly low compared to patients with Child's A and Child's B cirrhosis ( P < 0.001 and P < 0.05, respectively). There was a significant increase in the portal vein congestion index and splenic vein congestion index in patients with Child's C cirrhosis as compared to patients with Child's A cirrhosis ( P < 0.001). Among cirrhotic patients, the group with esophageal variceal bleeding had significantly greater splenic blood flow volume and splenic vein congestion index ( P < 0.001). Patients with ascites had significantly lower portal flow velocity ( P < 0.001) and higher portal vein congestion index and splenic vein congestion index ( P = 0.003 and P = 0.05, respectively) as compared to those without ascites. In this report we have shown that the decrease in blood flow and increased congestion indexes in the portal vein and splenic vein are related to the impairment of liver function in cirrhotic patients; these indexes may be valuable factors for predicting esophageal variceal bleeding.

American society of echocardiography guidelines and standards for performance of the fetal echocardiogram

Fetal echocardiography is the ultrasonic evaluation of the human fetal cardiovascular system. General antepartum obstetrical ultrasound has become a standard part of gestational care and is commonly used for the determination of fetal age, size, gender, or well-being and for the detection of congenital anomalies. A variety of maternal or fetal disorders may result in abnormality of the fetal cardiovascular system to a degree which demands evaluation at a level above and beyond that attainable with standard antepartum obstetrical ultrasound. In these circumstances, a fetal echocardiogram should be performed. Improved operator skill amongst physicians performing general antepartum obstetrical ultrasound, in combination with increased sensitivity of present day ultrasound systems, has resulted in improved detection of fetal cardiovascular abnormalities and increased requirements for more detailed evaluation. Congenital heart disease is the most common congenital anomaly found in the human. As the detection rates for congenital anomalies continue to increase, the demand for fetal echocardiography has grown. Accurate diagnosis of congenital heart disease via fetal echocardiography provides many benefits. It allows for a smooth transition between the preand post-natal states, with the opportunity to provide immediate care at birth, thereby avoiding the onset of hemodynamic compromise. Recent

Doppler Ultrasonography in Assessment of Fetal Well-being

After completing this article, readers should be able to: 1. Describe the calculations used to measure fetal systemic and placental vascular impedance in the umbilical artery via Doppler ultrasonography. 2. Delineate the two primary uses of measurement of middle cerebral artery flow velocity. 3. List the fetal conditions in which Doppler flow velocity has been studied. The Doppler principle, discovered by Johann Christian Andreas Doppler in 1842, (1) was used initially in astronomy and later in the military, in various branches of industry, and more recently in medicine. Doppler shift is based on the perceived change in frequency of an energy waveform as the source and the receiver move toward or away from each other. The Doppler shift principle applies to light waves as well as sound waves. In biology, Doppler ultrasonography is used noninvasively, primarily to measure flow velocity in blood vessels. Flow velocity depends on the volume and speed of effluent relative to the diameter of the vessel. Estimating fetal vascular resistance through study of Doppler flow velocity provides a means to assess, albeit indirectly, fetal physiology and pathology. Johnson and colleagues (2) in 1965, made the earliest mention of the use of Doppler effect in obstetrics. The use of Doppler ultrasonography to investigate the pattern of waveforms in the umbilical artery during pregnancy initially was reported in 1977 by Fitzgerald and Drumm. (3) Subsequently, Wladimiroff and associates (4) reported on Doppler assessment of cerebral blood flow in the human fetus. The addition of color mapping has enhanced the utility of the Doppler effect in sonographic assessment of the fetus. The fetal umbilical artery (UA) and middle cerebral artery (MCA) have evolved as the primary targets of fetal Doppler studies (Figs. 1 and 2). Figure 1. Color Doppler view of circle of Willis. Arrows show anterior (ACA), middle (MCA), and posterior cerebral …

Spinal anesthesia with bupivacaine decreases cerebral blood flow in former preterm infants.

Spinal anesthesia is commonly used in former preterm infants (FPI). In these patients, hypotension induced by spinal anesthesia may impair cerebral blood flow. We measured cerebral blood flow velocity (CBFV) by transcranial Doppler ultrasound to assess the effect of hypotension induced by spinal anesthesia on cerebral hemodynamics. Twelve FPI scheduled for inguinal hernia repair were operated under spinal anesthesia using 1 mg/kg isobaric 0.5% bupivacaine. Systolic, diastolic, and mean middle cerebral artery CBFV were measured at 5 min before and 5 min and 10 min after spinal anesthesia using a transcranial pulsed Doppler ultrasonography. Arterial blood pressure and heart rate were recorded simultaneously. Cerebral arteries resistance index (RI) was calculated as RI = (peak systolic CBFV - end-diastolic CBFV)/peak systolic CBFV. Diastolic CBFV decreased significantly from 30.0 +/- 11.1 cm/s to 20.1 +/- 8.4 cm/s at 5 min and to 20.1 +/- 7.0 cm/s at 10 min. RI increased significantly from 0.7 +/- 0.1 to 0.8 +/- 0.1 at 5 min and 10 min. Systolic, diastolic, and mean arterial blood pressures decreased significantly at the same time intervals. We suggest that in FPI, spinal anesthesia induces a decrease in cerebral blood flow related to changes in arterial blood pressure. Whether these changes have deleterious consequences remains to be determined. In former preterm infants having spinal anesthesia with bupivacaine, a decrease in cerebral blood flow velocity is displayed by middle cerebral artery transcranial Doppler examination.

Association of Vasa Previa at Delivery With a History of Second-Trimester Placenta Previa

Vasa previa is a rare obstetric disorder characterized by velamentous insertion of the fetal vessels over the mouth of the cervix. Reported fetal mortality estimates range from 58% to 73%. Ultrasonography has proved helpful for diagnosing this condition prenatally, improving outcomes, but little is known about any antecedent conditions that predispose to vasa previa. This study evaluated 1 possible factor, a history of second-trimester placenta previa, in 13 women presenting with vasa previa in the years 1991 through 2001. Deliveries totalled nearly 73,000 during this period. Vasa previa occurred once in every 5614 deliveries. Four control women with normal placentation were matched with each study patient. Eight of the 13 cases were detected in the third trimester by demonstrating fetal blood flow over the cervical os using pulsed color flow Doppler ultrasonography. Two other women presented at the time of amniotomy during labor with acute vaginal bleeding and subsequent fetal bradycardia. In 2 cases, the fetal vessels were palpated within the amniotic membranes during labor. One case was diagnosed after delivery, the fetus having died; torn fetal vessels were found when viewing the placenta. This woman had undergone membrane stripping during a prenatal visit at 41 weeks gestation. Three of the 13 women with vasa previa were nulliparous. Demographic features were similar in the study and control groups, although affected women tended to be older and to have undergone dilation and curettage more often than control women. Antepartum vaginal bleeding, cesarean delivery, and cesarean hysterectomy all were more frequent in study women. Two women, including the 2 with a dead fetus, were delivered vaginally. Nine of 13 women (69.2%) had placenta previa diagnosed by midtrimester ultrasonography. This was true for only 2 control women (3.8%), making the association highly significant. This retrospective study disclosed a statistically impressive relationship between vasa previa at delivery and a history of second-trimester placenta previa. Prospective studies of women with the latter condition would be of interest.

Ultrasonic rheological studies of a body lotion

To demonstrate the advantage of the gradient ultrasound pulse Doppler method in laminar tube flow, a rather complex body lotion is tested. The results reveal that the fluid shows Newtonian behaviour up to some critical shear rate γ ̇ c . For γ ̇ > γ ̇ c , a sudden phase separation can be detected: a Newtonian one close to the axis, followed by one in which the shear rate stays constant. Accompanying is this stress banding by slip. Customary means to account for this type of slip do not exist.

Oxygenation and hemodynamics in left and right cerebral hemispheres during induction of veno-arterial extracorporeal membrane oxygenation

Objective Oxygenation and hemodynamics in the left and right cerebral hemispheres were measured during induction of veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Study design Using near infrared spectrophotometry, effects of right common carotid artery (RCCA) and right internal jugular vein (RIJV) ligation and start of VA-ECMO on concentrations of oxyhemoglobin, deoxyhemoglobin, and cerebral blood volume (CBV) were evaluated in 10 newborn infants. Mean cerebral blood flow velocity (CBFV) in the major cerebral arteries was compared before and after the start of VA-ECMO (pulsed Doppler ultrasonography). Results RCCA ligation caused a decrease in oxyhemoglobin concentration and an increase in deoxyhemoglobin concentration. RIJV ligation caused no changes. Sixty minutes after the start of VA-ECMO, oxyhemoglobin concentration and CBV had increased, and deoxyhemoglobin concentration had decreased. There were no differences between the hemispheres. Mean CBFV had increased in the left internal carotid artery, and it increased equally in both middle cerebral arteries. Flow direction was reversed in the right internal carotid artery. Three patients had asymmetric cerebral lesions, not related to differences in the measurements between the cerebral hemispheres. Conclusion The initiation of VA-ECMO causes changes in cerebral oxygenation and hemodynamics but without a difference in effect on left and right cerebral hemispheres.

Estimation of Internal Filtration Flow Rate in a Dialyzer by a Doppler Ultrasonography

Several types of dialyzers with enhanced internal filtration have been introduced in order to increase solute clearance, especially in relatively larger molecular solutes. In these dialyzers, enhanced internal filtration increased convective transport of the solute in addition to diffusive transport. The internal filtration flow rate (QIF) has not, however, been measured in clinical situations, because none of monitoring techniques can measure this value. Herein, the QIF value was estimated during an experimental and an analytical study. Namely, we measured blood flow velocity in a cross‐sectional plane of the dialyzer by pulse Doppler ultrasonography. An in vitro study with bovine blood was carried out to determine the local blood flow velocity profile with a newly designed probe slider that enables parallel movement of the probe along the dialyzer. Furthermore, an analytical model was newly introduced to calculate changes in flow rate and pressure of blood and dialysate streams and solute concentrations along the dialyzer. The QIF value could be estimated by a simulation analysis to the experimental data using the analytical model.

Le Doppler pulsé transcrânien à la phase aiguë de l’infarctus cérébral

Transcranial pulsed Doppler sonography with or without imagery is used in the acute phase of ischemic stroke in order to define stroke mechanism and intracranial hemodynamic consequences. This non-invasive low-cost investigation can be undertaken rapidly, within 10 minutes if guided by focal symptomatology. It detects middle cerebral artery stenosis in >or=50 p. cent of cases with a sensitivity between 75 and 90 p. cent, comparatively with conventional angiography, and middle cerebral artery occlusion with 90 p. cent sensitivity. When a temporal acoustic window is lacking, intravenous injection of a contrast agent allows good visualization of the intracranial vessels and the circle of Willis, in two-third of cases. Moreover, transcranial Doppler data have good prognostic value and facilitate analysis of recanalization after thrombolytic therapy. Beside its diagnostic and prognostic interest, transcranial Doppler sonography using a 2 MHz frequency appears to have therapeutic impact by favoring the thrombolysis process. Future developments may include early and prolonged insonation of patients suffering from stroke.

Evaluation of fetal intrapartum hypoxia by middle cerebral and umbilical artery Doppler velocimetry with simultaneous cardiotocography and pulse oximetry.

To investigate fetal circulation at different stages of hypoxia during labor, and to study blood flow alterations in the brain and peripheral tissues, through simultaneous use of three non-invasive techniques. Ninety two pregnant women between 38 and 41 weeks of gestation, comparable for maternal age and parity, were simultaneously monitored with cardiotocography (CTG), continuous fetal pulse oximetry and Doppler ultrasonography during the first stage of labor. In 70 cases evaluation was successful, and useful data was obtained. Doppler waveforms were obtained before and during abnormal CTG patterns, of both the umbilical (UA) and middle cerebral artery (MCA) to measure the pulsatility index (PI), resistance index (RI), and flow velocity integral (FVI). The study population was divided in three groups, according to CTG and fetal pulse oximetry tracings: 20 term fetuses with normal CTG patterns and oxygen saturation (FSPO(2)) values >40%, 30 term fetuses with abnormal CTG patterns and FSPO(2) values between 30 and 40%, and 20 fetuses with abnormal CTG patterns and FSPO(2) values <30% for a time up to 2 min. These were studied and peripartum outcomes were compared. Redistribution of blood flow was noted at FSPO(2) values of 37%, in all groups. In the presence of reduced oxygen saturation (near to or below 30%), MCA Doppler showed significantly lower PI (1.06+/-0.33 vs.0.74+/-0.39, p=0.03) and RI (0.59+/-0.14 vs. 0.44+/-0.14, p=0.03), while that of the UA showed mildly higher resistance indices (0.98+/-0.14 vs. 1.28+/-0.50, p=0.01 and 0.57+/-0.12 vs. 0.79+/-0.24, p=0.004, respectively). When an oxygen saturation value of <30% was maintained for greater than 2 min, MCA Doppler indices reversed, likely indicating morbid fetal hypoxia. Differences in fetal outcomes between groups correlated with Doppler and pulse oximetry tracings. During active labor the fetus maintains oxygen supply to the brain by redistributing blood flow. In cases of hypoxia this is feasible for only 2 min. We note a strong correlation between fetal pulse oximetry, Doppler velocimetry of the MCA and UA, and fetal morbidity.

Doppler sonographic estimation of normal values for flow velocity and resistance indices in renal arteries of healthy infants

Summary. Colour coded Duplex sonography (CDI) is an important method for the judgement of renal perfusion in infancy. By means of CDI the renal artery (RA), the segmental renal arteries (SA) and the interlobar arteries (ILA) can be differentiated. By means of pulsed Doppler sonography flow parameters in renal vessels can be measured. As flow parameters in different renal arteries are age dependent, normal values of the flow velocities and resistance indices were estimated. We investigated 147 healthy children by CDI. Children were subdivided into 4 groups: 38 infants (< 1 year), 38 toddlers (> or = 1 year and < 6 years), 37 school children (> or = 6 and < 12 years) and 34 adolescents (> or = 12 and < 18 years). All children were investigated by computersonography with a 5 or 7,5 MHz transducer. In all children blood flow was measured in the RA, SA and ILA. From the flow profile peak systolic flow velocity (Vmax), endsystolic (Ves), enddiastolic (Ved) and time average (TAV) flow velocity as well as the resistance index (RI) were measured. Flow velocity and resistance indices were age dependent and related to the location within the renal vascular tree. The highest flow velocity was found in the renal artery, lowest in the ILA. In infants, Vmax in the RA was 51,5 +/- 13,4, in the SA 33 +/- 8 and in the ILA 19,5 +/- 5 cm/s. In toddlers, Vmax in the RA was 71,3 +/- 13,5, in the SA 43,6 +/- 8,5 and in the ILA 28,3 +/- 6,8 cm/s. In school age children, Vmax in the RA measured 80 +/- 18, in the SA 45,5 +/- 9,1 and in the ILA 27,9 +/- 5,3 cm/s. In adolescents, Vmax in the RA was 80,7 +/- 13,7, in the SA 46,8 +/- 11,8 and in the ILA 28 +/- 6,1 cm/s. From RA to SA the other flow velocity Ves, Ved, TAV decreased about 30 % and from SA to ILA about 30 %. Flow velocity in the different renal arteries was age dependent. The lowest flow velocity was found in newborns and infants, highest in elder school children and adolescents. The flow velocity markedly increased from infancy to early childhood whereas in elder children and adolescents a slower increase of the flow velocity could be found. Every flow velocity within the RA and AIL showed a statistically significant increase with increasing age (p < 0,0001). Resistance indices decreased from the renal artery to the interlobar arteries. The RI of infants within the RA was 0,82 +/- 0,11, within the SA 0,81 +/- 0,12 and within the AIL 0,73 +/- 0,17. In toddlers the RI within the RA was 0,71 +/- 0,08, within the SA 0,67 +/- 0,07 and within the ILA 0,65 +/- 0,08. In school age children the RI within the RA was 0,71 +/- 0,09, within the SA 0,66 +/- 0,08 and the ILA 0,58 +/- 0,10. In adolescents the RI within the RA was 0,69 +/- 0,06, within the SA 0,63 +/- 0,07 and within the ILA 0,60 +/- 0,06. Additionally, resistance indices decreased with increasing age. Statistical analysis showed a significant decrease with increasing age (p < 0,0001). Highest resistance indices could be found in early infancy and in the renal arteries, lowest resistance indices were measured in school age and adolescence and in the interlobar arteries. As flow velocity and resistance indices are age dependent and dependent on the location of the sample volume in different renal arteries, both parameters have to be considered if pathological flow parameters are measured. The determination of normal values of flow velocity and resistance indices in different renal arteries facilitate the judgement of pathologic flow parameters. For comparative controls flow measurements within the renal artery and interlobar arteries should be used.

Doppler flow velocity to measure the redistribution of fetal cardiac output in fetal stress

The pathophysiologic continuum of poor uterine and placental blood flow associated with fetal growth restriction has to be considered the major cause of poor birth outcomes. The main attention in this context is drawn to the possibilities of an early diagnosis of imminent fetal compromise prior to and under delivery. With regard to this, the detection of a reduced fetal oxygen saturation (fetal stress) plays a crucial role, whereat an acute incident causing fetal hypoxemia has to be differentiated from a chronic hypoxemic condition. An acute hypoxemia under delivery is best detected by cardiotocography. Due to its infrequent and unpredictible occurrence, an acute antenatal hypoxemia usually escapes common surveillance methods. Fetal biometry and pulsed Doppler sonography are to be considered the most suitable methods to diagnose chronic hypoxemic fetal conditions. The interrogation of a combination of peripheral and central vessels allow the sonologist to characterize the extend of a progressivly deteriorating oxygen supply. However, this correlation is not yet completely understood. Therefore, clinical consequences still have to be drawn by cardiotocographic findings indicating a global cardiac decompensation.

The cooling effect of liquid flow on the focussed ultrasound-induced heating in a simulated foetal brain.

There is a need to investigate the thermal effects of diagnostic ultrasound (US) to assist the development of appropriate safety guidelines for obstetric use. The cooling effect of a single liquid flow channel was measured in a model of human foetal brain and skull bone heated by a focussed beam of simulated pulsed spectral Doppler US. Insonation conditions were 5.7 micros pulses, repeated at 8 kHz from a focussed transducer operating with a centre frequency of 3.5 MHz, producing a beam of -6 dB diameter of 3.1 mm at the focus and power outputs of up to 255 +/- 5 mW. Brain perfusion was simulated by allowing distilled water to flow at various rates in a 2 mm diameter wall-less channel in the brain soft tissue phantom material. This study established that the cooling effect of the flowing water; 1. was independent of the acoustic source power, 2. was more effective close to the flow channel, for example, there was a marked cooling at a distance of 1 mm and negligible cooling at a distance of 3 mm from the channel; and 3. initially increased at low flow rates, but further increase above normal perfusion had very little effect.

Increased Plasma Adrenomedullin in Women With Recurrent Pregnancy Loss

In Brief OBJECTIVE To evaluate vascular changes and uterine perfusion in women with recurrent pregnancy loss. METHODS We measured plasma levels of adrenomedullin of 100 pregnant women in the midluteal phase of a nonpregnant cycle (control group: n = 62; recurrent pregnancy loss group: n = 38). We measured the pulsatility index (PI) in the uterine arteries by transvaginal pulsed Doppler ultrasonography at the same time. RESULTS The plasma level of adrenomedullin in women with recurrent pregnancy loss (5.6 ± 1.9, mean ± standard deviation) was significantly higher (P > .001) than that in control women (3.6 ± 1.7). Uterine arterial PI of women with recurrent pregnancy loss (2.70 ± 0.47) was significantly higher (P > .001) than that in control women (2.09 ± 0.39). Plasma level of adrenomedullin had a significant positive correlation with uterine arterial PI both in the control group (r = .58, P < .001) and in the recurrent pregnancy loss group (r = .78, P < .001). Both plasma adrenomedullin concentration (7.2 ± 2.3) and uterine arterial PI (3.06 ± 0.36) were significantly high in women with antiphospholipid antibodies. CONCLUSION Plasma adrenomedullin may serve as a useful biochemical marker for recurrent pregnancy loss caused by impaired uterine perfusion. The plasma level of adrenomedull in in women with recurrent pregnancy loss is significantly higher than that in control women.

Increased plasma adrenomedullin in women with recurrent pregnancy loss.

To evaluate vascular changes and uterine perfusion in women with recurrent pregnancy loss. We measured plasma levels of adrenomedullin of 100 pregnant women in the midluteal phase of a nonpregnant cycle (control group: n = 62; recurrent pregnancy loss group: n = 38). We measured the pulsatility index (PI) in the uterine arteries by transvaginal pulsed Doppler ultrasonography at the same time. The plasma level of adrenomedullin in women with recurrent pregnancy loss (5.6 +/- 1.9, mean +/- standard deviation) was significantly higher (P >.001) than that in control women (3.6 +/- 1.7). Uterine arterial PI of women with recurrent pregnancy loss (2.70 +/- 0.47) was significantly higher (P >.001) than that in control women (2.09 +/- 0.39). Plasma level of adrenomedullin had a significant positive correlation with uterine arterial PI both in the control group (r =.58, P <.001) and in the recurrent pregnancy loss group (r =.78, P <.001). Both plasma adrenomedullin concentration (7.2 +/- 2.3) and uterine arterial PI (3.06 +/- 0.36) were significantly high in women with antiphospholipid antibodies. Plasma adrenomedullin may serve as a useful biochemical marker for recurrent pregnancy loss caused by impaired uterine perfusion.

Color Doppler imaging of orbital vessels: personal experience and literature review.

Many Doppler imaging studies have been performed in recent years in a large number of ocular disorders because of improvements in the Doppler equipment used for detecting and measuring the low blood-flow velocities that are a requisite for the quantitative evaluation of blood flow in the orbital vessels. The ophthalmic artery, central retinal artery and vein, posterior ciliary arteries, and the superior ophthalmic vein can be easily identified using color Doppler sonography. The changes in local blood flow in these vessels assessed by spectral analysis pulsed Doppler sonography have been used to characterize and to obtain new insights into different nontumoral vascular disorders including carotid artery stenosis, central retinal vein occlusion, giant cell arteritis, glaucoma, diabetes, fistulas, and tumoral processes of the eye and orbit. Our experience has confirmed the important role of Doppler sonography in the assessment of subclinical changes in the vascular bed, in the understanding of different processes, for following up after specific treatments, and for determining the long-term prognosis of these various conditions.