Techniques for the measurement of the local myocardial extraction efficiency for inert diffusible contrast agents such as gadopentate dimeglumine

Abstract

We have previously shown that the concentration of Gd-DTPA as, a function of time ([Gd-DTPA]_t(t)) in the myocardium following an intravenous bolus injection of Gd-DTPA can be moldered using the Modified Kety Equation. Fitting this model to measurements of [Gd-DTPA]_t(t) in a region of myocardium would allow the determination of myocardial distribution volume (λ) and the product of flow (F) and extraction efficiency (E), i.e., FE. Thus, to measure F,E must be known. We describe here techniques developed to measure local values of E in normal and diseased myocardium. These techniques are valid for any inert diffusible MR contrast agent.