Measurement of rCBF

All clinical and many laboratory methods of measuring CBF or rCBF are indirect and may not produce directly comparable measurements. It is also important to treat results from any one method with caution and attribute any observed phenomena to physiological effects only when demonstrated by two or more independent techniques. Methods of measuring CBF may be regional or global and applicable either to humans or primarily to experimental animals. All of these methods have advantages and disadvantages All methods that provide absolute estimates of rCBF use one of two principles: they either measure the distribution of a tracer or estimate rCBF from the wash-in or wash-out curve of an indicator. Other techniques do not directly estimate rCBF but can be used to either measure a related flow variable (such as arterial flow velocity) or infer changes in flow from changes in metabolic parameters. These issues are addressed in detail in Chapter 00.

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