OBJECTIVE To study the Doppler velocimetry of the fetal middle cerebral artery in pregnancies complicated by placental insufficiency, and to verify its role in the prognosis of neonatal survival. METHODS This was a prospective study of 93 pregnant women with diagnosis of placental insufficiency detected before the 34(th) week of pregnancy. Placental insufficiency was characterized by abnormal...

OBJECTIVE We aimed to evaluate ductus venosus Doppler waveforms before and after amniocentesis in order to investigate any effect of amniocentesis on fetal myocardial hemodynamics. We also evaluated the umbilical artery, uterine artery and fetal mid-cerebral artery Doppler waveforms in order to investigate any relationship with ductus venosus Doppler changes. METHODS The study population cons...

We investigated the validity of transcranial Doppler recordings for the analysis of dynamic responses of cerebral autoregulation. We found no significant differences in percentage changes among maximal (centerline) blood flow velocity, cross-sectional mean blood flow velocity, and signal power-estimated blood flow during 24-mm Hg stepwise changes in arterial blood pressure. We investigated bloo...

BACKGROUND AND PURPOSE Microemboli observed during coronary angiography can cause silent ischemic cerebral lesions. The aim of this study was to investigate if the number of particulate cerebral microemboli during coronary angiography is influenced by access site used. METHODS Fifty-one patients with stable angina pectoris referred for coronary angiography were randomized to right radial or r...

BACKGROUND AND PURPOSE The clinical course of stroke due to occlusion of the internal carotid artery is influenced by amount of collateral flow. We measured mean frequency shifts in the middle cerebral artery by transcranial Doppler ultrasonography to determine its prognostic value. METHODS Patients with proven extracranial occlusion of the internal carotid artery and ipsilateral hemispheral ...

BACKGROUND AND PURPOSE We correlated the mean transcranial Doppler blood flow velocity (FVm) during carotid endarterectomy with the functional collateral pathway(s) documented by angiography. METHODS Three patient groups were established: group 1 was dependent on the anterior communicating artery, group 2 on the anterior communicating artery and ipsilateral posterior communicating artery, and...

BACKGROUND AND PURPOSE The clinical application of intracranial near-infrared spectroscopy in adults has been hampered by concerns over contamination from extracranial tissues. The NIRO 300 (Hamamatsu Photonics) provides continuous online measurements of hemoglobin and cytochrome oxidase concentrations and a calculated tissue oxygen index (TOI). The present study seeks confirmation of the anato...

It is obvious that a noninvasive technique that can provide continuous measurements of blood flow through a cerebral artery would be very valuable for clinical and investigative purposes. The most promising approach to the development of such a technique involves the use of ultrasound for the measurement of blood flow velocity. Since blood flow through a vessel is equal to the instantaneous ave...

Migraine is considered a neurovascular disease involving dilatation of cerebral arteries. Nitric oxide (NO) donors induce dilatation of cerebral and extracranial arteries and migraine, but NO has several mechanisms of action in addition to its cyclic guanosine monophosphate (cGMP)-mediated vasodilatation. We examined whether sildenafil (Viagra), a selective inhibitor of cGMP-hydrolysing phospho...

It is obvious that a noninvasive technique that can provide continuous measurements of blood flow through a cerebral artery would be very valuable for clinical and investigative purposes. The most promising approach to the development of such a technique involves the use of ultrasound for the measurement of blood flow velocity. Since blood flow through a vessel is equal to the instantaneous ave...