Indicator Dilution Time-Activity Curves Demonstrated By Rapid Magnetic-Resonance Imaging Techniques And Paramagnetic Contrast Agent

Indicator dilution time-activity curves are demonstrated using magnetic resonance imaging (MRI) as the detector and a paramagnetic contrast agent as the indicator. Manganese chloride was injected into a flow phantom. The nuclear magnetic resonance (MR) intensity was measured downstream. Several flow rates were used. The observed MR intensity decreased as the paramagnetic indicator passed through the imaging plane. The qualitative changes of the MR intensity decrease varied in accordance with indicator dilution theory. The equations for gradient refocused echoes, paramagnetic compound relaxation changes, and the indicator dilution analysis were combined and evaluated. Quantitative analysis demonstrates several problems in its implementation.