A comparison of measurements of cerebral blood flow in the rabbit using laser Doppler spectroscopy and radionuclide labelled microspheres.

Laser Doppler spectroscopy has been evaluated for the measurement of cerebral blood flow (CBF) by correlation with simultaneous measurements by radionuclide labelled microspheres. The experimental procedures were carried out on five anaesthetised rabbits. The cortical tissue was exposed by means of a small burr hole and illuminated by a helium neon laser (632.8 nm). Reflected light was detected using a silicon photodiode, and CBF was calculated continuously from the power of the frequency weighted Doppler spectrum in the reflected light. Three successive measurements of CBF were made using the microsphere technique. Following an initial baseline measurement, CBF was increased by an infusion of metaraminol and then reduced by controlled haemorrhage. Laser Doppler spectroscopy provided continuous monitoring of blood flow fluctuations and during the haemorrhage it was possible to demonstrate CBF autoregulation until the mean blood pressure fell below 6.7 kPa (50 mmHg). A regression analysis was performed between the simultaneous CBF measurements from the two techniques using a least squares best fit straight line analysis (r = 0.92, P less than 0.001). It was concluded that the flow computed from laser Doppler spectroscopy varied linearly with CBF and offers the unique advantage of continuous and instantaneous measurements even during nonsteady state flow.

[1]  C E Riva,et al.  Laser Doppler measurement of relative blood velocity in the human optic nerve head. , 1982, Investigative ophthalmology & visual science.

[2]  P A Flecknell,et al.  Midazolam and fentanyl-fluanisone: assessment of anaesthetic effects in laboratory rodents and rabbits , 1984, Laboratory animals.

[3]  A. Bill.  Effects of indomethacin on regional blood flow in conscious rabbits--a microsphere study. , 1979, Acta physiologica Scandinavica.

[4]  S. Chien,et al.  Regional Cerebral Blood Flow and Oxygen Consumption of the Canine Brain During Hemorrhagic Hypotension , 1984, Stroke.

[5]  A M Rudolph,et al.  Use of radioactive microspheres to assess distribution of cardiac output in rabbits. , 1968, The American journal of physiology.

[6]  Gert E. Nilsson,et al.  Evaluation of a Laser Doppler Flowmeter for Measurement of Tissue Blood Flow , 1980, IEEE Transactions on Biomedical Engineering.

[7]  R L Bowman,et al.  Continuous measurement of tissue blood flow by laser-Doppler spectroscopy. , 1977, The American journal of physiology.

[8]  Toyoichi Tanaka,et al.  Blood Velocity Measurements in Human Retinal Vessels , 1974, Science.

[9]  H. Inhaber.  Energy: calculating the risks. , 1979, Medical research engineering.

[10]  W D Heiss,et al.  Comparative Studies of Regional CNS Blood Flow Autoregulation and Responses to CO2 in the Cat: Effects of Altering Arterial Blood Pressure and PaCO2 on rCBF of Cerebrum, Cerebellum, and Spinal Cord , 1984, Stroke.

[11]  M. Stern,et al.  In vivo evaluation of microcirculation by coherent light scattering , 1975, Nature.

[12]  J I Hoffman,et al.  Blood flow measurements with radionuclide-labeled particles. , 1977, Progress in cardiovascular diseases.

[13]  P. Oberg,et al.  Use of a new laser Doppler flowmeter for measurement of capillary blood flow in skeletal muscle after bullet wounding. , 1979, Acta chirurgica Scandinavica. Supplementum.

[14]  P. Gygax,et al.  Hypotension induced changes in cerebral microflow and EEG and their pharmacological alterations. , 2009, Acta medica Scandinavica. Supplementum.