Assessment of parameters influencing the blood flow velocities in cerebral arteries of the rat using ultrasonographic examination.

OBJECTIVES

Rat models of cerebrovascular diseases are used for a variety of human pathologies comprising ischemic stroke or subarachnoid hemorrhage. Whereas in neuro-intensive care, Doppler ultrasonographic examination of major cerebral arteries is a common diagnostic tool, only few data exist concerning the animal model. We therefore studied cerebral blood flow velocities in the rat by ultrasonographic triplex mode.

METHODS

Female Wistar rats underwent a large craniectomy and baseline values for blood flow velocities were obtained by 399 examinations in 52 animals. Vessel diameters were assessed by 301 examinations in 39 animals. Finally, in 26 animals, continuous measurements of blood flow velocities were performed. For a duration of more than 30 minutes, values in the anterior trunk, the left carotid artery and the basilar artery were obtained every 60-90 seconds with simultaneous detection of heart rate.

RESULTS

Blood flow velocities in the anterior part of cerebral circulation were faster than those in the posterior part and showed higher standard deviation. Flow velocities in arteries belonging to the anterior circulation changed in relation to carotid flow velocity and heart rate, whereas the velocity in the basilar artery showed much lower correlation to carotid flow velocity or heart rate.

DISCUSSION: Ultrasonographic triplex mode examination of cerebral vessels offers a reproducible method to study rat cerebral blood flow velocities and vessel diameters. In combination with monitoring of systemic hemodynamic parameters, it can provide a detailed description of the vascular response to drugs, experimental stroke or subarachnoid hemorrhage.