The injection of indicators in the blood stream is used for several diagnostic measure ments of the cardiovascular system functionality. An indicator is a non-toxic substance that can be detected by a specific sensor. The detection often implies a contact between indicator and sensor. As a result, the measurement is invasive, i.e. a catheter must be inserted through the blood vessels in the measurement site. The invasiveness issue can be overcome by means of contrast imaging techniques. Contrast agents are substances that enhance the signal detected by specific imaging modalities. The measurement of the contrast (or indicator) concentration versus time results in an indicator dilution curve. Several hemodynamic models can be adopted for the curve interpretation and for the estimation of the cardiovascular parameters of interest. This chapter provides an overview on the indicator dilution theory and the clinical techniques that can be adopted for the measurement of dilution curves. Both invasive and minimally invasive techniques are discussed. Particular attention is dedicated to the use of medical imaging techniques such as ultrasound and magnetic resonance imaging. These methods promise to open new possibilities for minimally invasive cardiovascular diagnostics based on indicator dilution.
|Title of host publication
|Biomechanical Systems Technology : Cardiovascular Systems
|Place of Publication
|Number of pages
|Published - 2007