PURPOSE The arterial pulsatility index (PI) is measured by transcranial Doppler ultrasonography (TCD) and is postulated to reflect the vascular resistance distal to the artery being examined. An increased PI of the intracranial artery is often reported with diabetes mellitus (DM), old age, hypertension, intracranial hypertension, vascular dementia, and small artery disease. Microvascular compli...

Aim—To determine whether antenatal administration of thyrotrophin releasing hormone (TRH), to promote lungmaturation, alters blood flow through the fetal middle cerebral, umbilical artery, or ductus arteriosus and through the maternal uterine arteries. Methods—The eVect of transplacentally administered TRH on the fetal circulation was prospectively evaluated in 30 patients between 24 and 34 wee...

Two cases of progressive hemiplegia were closely followed by daily clinical examination. In both, the CT scan and CSF were normal on admission. In both, objective aggravation occurred in three or more steps over four days, progressing from minor finger clumsiness to total paralysis of the arm. In both cases a second CT scan a day after appearance of hemiplegia demonstrated a lacune in the coron...

AIM To determine whether antenatal administration of thyrotrophin releasing hormone (TRH), to promote lung maturation, alters blood flow through the fetal middle cerebral, umbilical artery, or ductus arteriosus and through the maternal uterine arteries. METHODS The effect of transplacentally administered TRH on the fetal circulation was prospectively evaluated in 30 patients between 24 and 34...

Magnetic resonance (MR)-guided stereotactic techniques that allow precise in vivo anatomic location have recently been developed (1). Using such a system, we tested the hypothesis that we are insonating from the midpoints of the M 1 segment of the middle cerebral artery and A 1 segment of the anterior cerebral artery during clinical hand-held transcranial Doppler examinations. We also compared ...

The cerebral blood flow velocity (CBFV) of middle cerebral artery (MCA) was detected during the fatigue driving using Transcranial Doppler. The CBFV was also analyzed after the fatigue driving by different means of relaxation to alleviate brain fatigue. The results show that the CBFV in MCA is reduced by driving fatigue.

BACKGROUND To determine the effect of vasovagally mediated syncope on the cerebral circulation, transcranial Doppler sonography was used to assess changes in cerebral blood flow velocity during head-upright tilt-induced syncope. METHODS AND RESULTS Thirty patients (17 men and 13 women; mean age, 43 +/- 22 years) with recurrent unexplained syncope were evaluated by use of an upright tilt-table...

The aim of this study was to assess if heavy alcohol drinking influences blood flow velocity in cerebral arteries. Blood flow velocity (V(mean)) in the middle cerebral artery was measured by transcranial Doppler sonography (TCD) in heavy alcohol drinkers. Significantly decreased V(mean) was found in comparison with healthy volunteers.

BACKGROUND AND PURPOSE An extremely low pulsatile cerebral perfusion can result in a massive cerebral infarction and poor outcome. We report a patient who had complete recovery from initial neurological deficits in spite of nonpulsatile perfusion in the middle cerebral artery. METHODS We used carotid duplex and transcranial Doppler to evaluate cerebral hemodynamics and the National Institutes...

BACKGROUND AND PURPOSE Cerebral embolism has been implicated in the development of cognitive and neurological deficits following bypass surgery. This study proposes methodology for estimating cerebral air embolus volume using transcranial Doppler sonography. METHODS Transcranial Doppler audio signals of air bubbles in the middle cerebral artery obtained from in vivo experiments were subjected...