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Doppler ultrasonographic measurement of blood flow velocities in major cerebral arteries of the rat using triplex mode

Abstract Objective: In patients with subarachnoid hemorrhage, delayed cerebral ischemia caused by vasospasm of major cerebral arteries is an important factor of morbidity. While Doppler ultrasonographic monitoring of blood flow velocities is a routine bedside examination in these patients, the current rodent models of vasospasm do not include this technique. In this article, we present an extended craniectomy in rats, which allows for direct angle-corrected Doppler ultrasonographic examination of major cerebral vessels. Methods: Ultrasonographic examination employs a triplex window displaying simultaneously B-mode, colour coded vessel rendering and Doppler-assessment of blood flow velocity. The animals receive anesthesia for the measurements, which are repeated several times a week. Results: Mean flow velocities determined by 116 measurements in 16 animals are (cm/s): truncus cerebri anterius: 8.16, arteria pericallosa: 7.49, arteries (Aa.) cerebri anteriores: 7.76, Aa. carotides: 8.76, Aa. cerebri mediae: 8.55, Aa. cerebri posteriores: 5.27, artery (A.) basilaris: 5.90. Discussion: We describe the direct intravital detection of blood flow velocities in major cerebral vessels of the rat. The technique allows for simultaneous visualization of intracranial structures, vessel diameters and cerebral blood flow velocities. Our ongoing research focuses on determining normal values in a larger population of animals and examining the feasibility of the technique regarding the rodent model of vasospasm.