Cerebral circulation during endotoxic shock with special emphasis on the regional cerebral blood flow in vivo

1986 ◽  
Vol 7 (7) ◽  
pp. 531-540 ◽  
Author(s):  
JAN T. CHRISTENSON ◽  
JYRKI T. KUIKKA ◽  
AZU OWUNWANNE ◽  
ABDULAZIZ A. ALA-SARRAF
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Cerebral Circulation ◽  
Regional Cerebral Blood Flow ◽  
Endotoxic Shock ◽  
Regional Cerebral Blood

scholarly journals A Simplified in vivo Autoradiographic Strategy for the Determination of Regional Cerebral Blood Flow by Positron Emission Tomography: Theoretical Considerations and Validation Studies in the Rat

1982 ◽  
Vol 2 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Myron D. Ginsberg ◽  
Alan H. Lockwood ◽  
Raul Busto ◽  
Ronald D. Finn ◽  
Cathy M. Butler ◽  
...  
Keyword(s):  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Regional Cerebral Blood Flow ◽  
Animal Studies ◽  
Blood Flow Rate ◽  
Emission Tomography ◽  
Regional Cerebral Blood ◽  
Positron Emission

A simplified mathematical model is described for the measurement of regional cerebral blood flow by positron emission tomography in man, based on a modification of the autoradiographic strategy originally developed for experimental animal studies. A modified ramp intravenous infusion of radiolabeled tracer is used; this results in a monotonically increasing curvilinear arterial activity curve that may be accurately described by a polynomial of low degree (= z). Integrated cranial activity C̄ B is measured in regions of interest during the latter portion of the tracer infusion period (times T1 to T2). It is shown that [Formula: see text] where each of the terms A x is a readily evaluated function of the blood flow rate constant k, the brain:blood partition coefficient for the tracer, the cranial activity integration limits T1 and T2, the coefficients of the polynomial describing the arterial curve, and an iteration factor n that is chosen to yield the desired degree of precision. This relationship permits generation of a table of C̄ B vs. k, thus facilitating on-line computer solution for blood flow. This in vivo autoradiographic paradigm was validated in a series of rats by comparing it to the classical autoradiographic strategy developed by Kety and associates. Excellent agreement was demonstrated between blood flow values obtained by the two methods: CBF in vivo = CBFclassical X 0.99 − 0.02 (units in ml g−1 min−1; correlation coefficient r = 0.966).

scholarly journals The in vivo Autoradiographic Measurement of Regional Cerebral Blood Flow Using Stable Xenon and Computerized Tomography: The Effect of Tissue Heterogeneity and Computerized Tomography Noise

1982 ◽  
Vol 2 (2) ◽  
pp. 173-178 ◽  
Author(s):  
D. A. Rottenberg ◽  
H. C. Lu ◽  
K. J. Kearfott
Keyword(s):  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Brain Tissue ◽  
Computerized Tomography ◽  
Measurement Errors ◽  
Regional Cerebral Blood Flow ◽  
Regional Cerebral Blood ◽  
Tissue Heterogeneity ◽  
Xenon Ct

We have studied the effect of brain tissue (gray matter–white matter) heterogeneity and computerized tomography (CT) noise on the accuracy of xenon CT measurements of regional cerebral blood flow (rCBF) based upon “autoradiographic” and multiple-scan washin protocols, The results of our mathematical analysis indicate that both protocols are associated with a variety of measurement errors that lead to unacceptable and, to a large extent, unpredictable uncertainties in calculated values of rCBF. Brain tissue heterogeneity and high volumetric flow rates may—even in the absence of movement artifact and CT noise—lead to measurement errors in excess of 20%. Moreover, CT noise is additive in regard to these errors, and constitutes the most confounding variable of all.

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