Continuous assessment of relative cerebral blood volume in transient ischemia using steady state susceptibility-contrast MRI.

The utility of a noninvasive steady state susceptibility-contrast MRI technique for continuous measurement of relative cerebral blood volume (rCBV) during global transient ischemia and subsequent hyperemia in a feline ischemia model is demonstrated. The measurements were obtained during a 10-min period of occlusion and 1-h period of reperfusion. Maximal hyperemic responses in gray matter, basal ganglia, and white matter (observed at 7,7, and 5 min, respectively) were 1.

Doppler monitoring of middle cerebral artery emboli from carotid stenoses.

The aim of this study was to prove the existence of clinically silent embolization arising from carotid stenoses. Simultaneous bilateral transcranial Doppler sonography of the middle cerebral artery was carried out during 10 minutes in 30 patients having ultrasonically demonstrated unilateral (n = 12) or bilateral internal carotid stenoses (n = 18). Twenty-four of the stenoses were clinically considered to be symptomatic and 24 were asymptomatic.

Measurement of cerebrovascular changes in cats after transient ischemia using dynamic magnetic resonance imaging.

Background And Purpose: Hemodynamic changes associated with acute ischemia cannot be measured with conventional nuclear magnetic resonance imaging. In this study, we used dynamic susceptibility-contrast magnetic resonance imaging to measure the changes in vascular transit time and relative cerebral blood volume in a feline occlusion-reperfusion model.

Methods: Dynamic susceptibility-contrast measurements were obtained before and during 10 minutes of global cerebral ischemia and for up to 3 hours after the onset of reperfusion.

[Assessment of cerebral autoregulation using transcranial Doppler sonography under lower body negative pressure].

A novel technique for transcranial Doppler sonographic assessment of cerebral autoregulation was tried out in 20 healthy volunteers, ten of them right-handed and ten left-handed. A fall in arterial blood pressure was produced through lower body negative pressure (LBNP) of -50 mmHg during 1 min. The Doppler shift signal of both middle cerebral arteries was recorded simultaneously and analyzed digitally to obtain mean Doppler shift frequency and Doppler signal power.

Expression of c-fos-like immunoreactivity in brainstem after meningeal irritation by blood in the subarachnoid space.

The expression of c-fos protein was examined by immunohistochemistry in serial sections of brainstem following the instillation of either autologous arterial blood (0.3 ml) or mock cerebrospinal fluid (0.3 ml) through a catheter placed in the cisterna magna, or following catheter placement alone in pentobarbital-anesthetized Sprague-Dawley rats.