Middle Cerebral Artery Blood Flow Velocimetry

We investigated 1) the regional distribution of cerebral blood flow (CBF), 2) the influence of end-tidal Pco2 (PetCO2) on CBF, and 3) the potential for an extracranial blood "steal" from the anterior brain region during passive hyperthermia. Nineteen (13 male) volunteers underwent supine passive heating until a steady-state esophageal temperature of 2°C above resting was established. Measurements were obtained 1) during normothermia (Normo), 2) during poikilocapnic hyperthermia (Hyper), and 3) during hyperthermia with PetCO2 and end-tidal Po2 clamped to Normo levels (Hyper-clamp)...

BACKGROUND: To determine whether the phosphodiesterase type 5 inhibitor, Sildenafil citrate, affects uteroplacental perfusion. MATERIALS AND METHODS: Based on a randomized double-blinded and placebo-controlled trial, forty one pregnant women with documented intrauterine growth retardation at 24-37 weeks of gestation were evaluated for the effect of a single dose of Sildenafil citrate on uteroplacental circulation as determined by Doppler ultrasound study of the umbilical and middle cerebral arteries...

Gestational diabetes mellitus (GDM) is one of the most common complications in pregnancies. Evaluating other conditions, including intra uterine growth restriction and pre-eclampsia, some studies have shown significant changes in blood flow velocity of fetal middle cerebral artery (MCA). Our study is one of the few that has aimed to assess the effects of GDM on Doppler parameters of the fetal MCA and umbilical artery (UA) and to compare with normal pregnancies. This cross-sectional study was performed on 66 pregnant women, including 33 women with GDM and the others without it, in Akbar-Abadi University Hospital in Tehran, Iran during 2010-2011...

This study experimentally investigated the instability of flow impingement in a cerebral aneurysm, which was speculated to promote the degradation of aneurysmal wall. A patient-specific, full-scale and elastic-wall replica of cerebral artery was fabricated from transparent silicone rubber. The geometry of the aneurysm corresponded to that found at 9 days before rupture. The flow in a replica was analysed by quantitative flow visualization (stereoscopic particle image velocimetry) in a three-dimensional, high-resolution and time-resolved manner...

A case of an umbilical cord collision diagnosed in the first trimester of a monochorionic monoamniotic twin pregnancy is presented. An intensive surveillance included ultrasound monitoring with color and spectral Doppler and fetal echocardiography. The first signs of fetal distress were observed at 31 weeks of gestation. The brain sparing effect as well as a periodic appearance of the "notch" in the wave forms obtained from the umbilical artery from the collision region were observed. In the first ultrasound scan there were no abnormalities in twin I...

There are various biophysical methods used for diagnosing and monitoring foetal well being using in intra-uterine growth restriction foetus, out of which Doppler velocimetry proved to possess the predictive capacity in diagnosing and management of intra-uterine growth restriction foetuses. The objectives were to study Doppler velocimetry of foetal umbilical artery and middle cerebral artery in diagnosing intra-uterine growth restriction and to correlate Doppler finding with perinatal outcome. Random 50 patients with singleton pregnancies admitted in RG Kar Medical College and Hospital were studied in a duration of 1 year...

TO DATE, TWO MAIN CATEGORIES OF OCT TECHNIQUES HAVE BEEN DESCRIBED FOR IMAGING HEMODYNAMICS: Doppler OCT and OCT angiography. Doppler OCT can measure axial velocity profiles and flow in arteries and veins, while OCT angiography can determine vascular morphology, tone, and presence or absence of red blood cell (RBC) perfusion. However, neither method can quantify RBC velocity in capillaries, where RBC flow is typically transverse to the probe beam and single-file. Here, we describe new methods that potentially address these limitations...

OBJECTIVE: To determine the resistance index (RI) and pulsatility (PI) in the umbilical artery (UA) in prediction of abnormal fetal heart rate during labor and poor fetal outcome in term pregnancy. MATERIAL AND METHODS: The study included 148 patients at term in uncomplicated pregnancy Daily evaluation of blood flow in the UA was performed and PI and RI were calculated. The last value before delivery was taken for the analysis. In turn predictive value of Doppler parameters has been determined in the prediction of abnormal FHR during labor and abnormal newborn condition...

The aim of our study was to evaluate the middle cerebral artery velocimetry before and after intrauterine blood transfusion in immune hydrops fetalis. The current study was conducted in a tertiary research hospital, from February 2009 to January 2011. Nineteen intrauterine blood transfusions performed during the study period. The factors recorded were age of the mothers, gestational weeks, pre-transfusion fetal hematocrit and post-transfusion fetal hematocrit, and also middle cerebral artery peak systolic velocimetry (MCA-PSV) was detected and recorded before and after intrauterine transfusion...

Doppler analysis of the umbilical and uterine arteries has long been performed in perinatal medicine to assess fetal health and maternal risk for preeclampsia. Several other vessels can be interrogated to obtain additional, vital information. Velocimetry in the fetal middle cerebral artery can yield evidence of the presence or absence of anemia and, in cases of delayed growth, of the risk of hypoxic damage. Ductus venosus waveforms are a very good indicator of impeding fetal jeopardy and should be used when umbilical artery waveforms become abnormal...

OBJECTIVE: The role of hemodynamics in the growth of intracranial aneurysms is not completely clear. We present a hemodynamic study with two adjacent unruptured aneurysms arising from one parent artery but growing in different ways. This study aimed to investigate whether there were differences in hemodynamic characteristics between the two growing aneurysms. METHODS: A 62-year-old female patient presented with six unruptured intracranial aneurysms. Catheter angiography at 6-month intervals revealed that two aneurysms located adjacently at the right posterior inferior cerebellar artery were growing over a 1-year period...

PURPOSE: to determine the best Doppler flow velocimetry index to predict small infants for gestational age (SGAI), in pregnant women with hypertensive syndromes. METHODS: a cross-sectional study was conducted enrolling 129 women with high blood pressure, submitted to doppler velocimetry up to 15 days before delivery. Women with multiple fetuses, fetal malformations, genital bleeding, placental abruption, premature rupture of fetal membranes, smoking, use of illicit drugs, and chronic diseases were excluded...

OBJECTIVE: To determine the resistance index (RI) and pulsatility (PI) in the middle cerebral artery (MCA) in prediction of abnormal fetal heart rate during labor and poor fetal outcome in term pregnancy. MATERIAL AND METHODS: The study included 148 patients at term in uncomplicated pregnancy Daily evaluation of blood flow in the MCA was performed and PI and RI were calculated. The last value before delivery was taken for the analysis. The predictive value of Doppler parameters has been determined in turn to predict abnormal FHR during labor and abnormal newborn condition...

BACKGROUND: Despite the existence of various published studies regarding the effects of tobacco smoking on pregnancy, and especially in regards to placental blood flow and vascular resistance, some points still require clarification. In addition, the amount of damage due to tobacco smoking exposure that occurs has not been quantified by objective means. In this study, we looked for a possible association between flow resistance indices of several arteries and the levels of urinary cotinine and the concentration of carbon monoxide in the exhaled air (COex) of both smoking and non-smoking pregnant women...

Feto-maternal red cell alloimmunization is defined by the presence in a pregnant woman of alloantibodies directed against blood group antigens present on the red blood cells of the fetus and inherited from the father. It arises from the immune response to a first contact to these same antigens during a prior transfusion, transplant or pregnancy. The placental transfer and the fixation of the antibodies on the fetal red cells antigenic targets lead to a haemolysis in the fetus and the newborn. The resulting haemolytic disease can show different clinical forms, from a mild anaemia with neonatal hyperbilirubinemia to a major fetal damage with stillbirth caused by hydrops fetalis...

Doppler velocimetry of the middle cerebral artery (MCA) has played a major role in fetal medicine for the last 23 years, both in intrauterine growth-restricted (IUGR) and anemic fetuses. Its utility in the diagnosis and management of cases of fetal anemia was initially demonstrated in cases of red cell alloimmunization and later extended to other types of anemia. In addition, MCA Doppler studies are crucial in the evaluation of IUGR fetuses. This article is a review of the role of the MCA in these 2 conditions...

OBJECTIVE: The study was designed as a prospective non-interventional, observational study to elucidate the potential value of fetal middle cerebral artery Doppler velocimetry to identify brain-sparing flow in a surveillance program for suspected intrauterine growth restriction (IUGR). MATERIAL AND METHODS: The study was carried out at Skåne University Hospital, Malmö, Sweden. One hundred and twenty-six single pregnancies suspected of IUGR at ≥36 gestational weeks were assessed...

OBJECTIVE: To assess the accuracy of the combined use of the cardiofemoral index (CFI) and the middle cerebral artery peak systolic velocity (MCA-PSV), converted to multiples of the median (MoM), as noninvasive means to detect severe fetal anemia. METHOD: We measured CFI and MCA-PSV MoM in 37 fetuses just before their first (n=37), second (n=22), and third (n=14) cordocenteses and transfusions. Then, using 2 different criteria for severe fetal anemia detection (Hb deficit ≥7 g/dL and hemoglobin level ≤0...

OBJECTIVE: To determine the predictive value of middle cerebral artery (MCA) to uterine artery pulsatility index (PI) ratio in preeclamptic patients. METHODS: This prospective cross-sectional study was performed on 64 preeclamptic and 131 normal pregnancies at or beyond 26 weeks of gestation between June 2007-August 2008 in the high-risk pregnancy unit of Dr. Zekai Tahir Burak Women Health Teaching and Research Hospital, Ankara. Doppler blood flow velocimetry of the uterine and umbilical arteries and fetal MCA was measured...

OBJECTIVES: To determine the longitudinal trends and rates of conversion of normal to abnormal uterine (UtA), umbilical (UA) and middle cerebral artery (MCA) Doppler velocimetry throughout the third trimester in late-onset small-for-gestational-age (SGA) fetuses. METHODS: UtA, UA and MCA Doppler velocimetry was serially performed in a cohort of singleton consecutive late-onset SGA fetuses with normal Doppler values at diagnosis. The rate of conversion of normal to abnormal Doppler values was evaluated by survival analysis...