The cerebral blood flow velocity in the middle cerebral artery of an canine animal model was measured using the Doppler Ultrasound technique. A transducer was designed with a 20 MHz piezoelectric crystal and used for the application. An in vitro calibration system was designed and machined for the purpose of testing and calibrating every transducer before using it in vivo. Preliminary tests included experiments on the in vitro system and measurement of blood flow velocity in the human wrist artery (metacarpal artery). The effect of using different transmission media (agarose and gelatin) was determined through the many in vitro and animal experiments. A design of surgical preparation and setup which included instrumentation and procedure was developed. The in vivo measures included blood flow velocity in the femoral, left gastric and mesenteric arteries of a mouse (14.5cm/s to 17.4cm/s; 12cm/s to l4cm/s; 25cm/s to 30cm/s respectively), middle cerebral artery (MCA) of a pig (7.5cm/s to 8.5cm/s), the MCA of a dog (5.5cm/s to 6cm/s) and drug response as an indication of instrument sensitivity (increase from 6cm/s to 10cm/s with introduction of Forskolin). The values obtained matched those in the published literature. Fast Fourier Transformations were used to write programs in MATLAB which served as the tool for data analysis.
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