The measurement of liver blood flow: a review of experimental and clinical methods.

Changes in hepatic blood flow reflect adaptive responses of the liver to injury, regeneration, and the development of disease states. The measurement of hepatic blood flow is, however, technically challenging and although theoretically useful has not become routine in clinical work. The different techniques that have been developed for quantitative measurement of hepatic blood flow require careful interpretation of the results obtained but are frequently applied without careful considerations of their technical limitations. In particular, many noninvasive techniques depend on good hepatocellular function and are thus irrelevant under most clinical conditions. Many other potentially useful techniques are poorly validated and standardized and there is a need for further research into smethodology. This review summarizes the salient technical features of the different techniques for quantitative measurement of hepatic blood flow. The techniques are divided into invasive, minimally invasive, and noninvasive categories and the relevance of each technique to both routine clinical application or research is discussed.