Quantification of myocardial blood flow and extracellular volumes using a bolus injection of Gd-DTPA: Kinetic modeling in canine ischemic disease

In order to clarify the relationship between coronary artery disease (including myocardial infarction) and image contrast in gadolinium diethylenetriaminepentaacetic acid (Gd‐DTPA‐enhanced MRI it was decided to model the myocardial tissue distribution and clearance of Gd‐DTPA using the modified Kety equation. Using a canine model, myocardial tissue Gd‐DTPA concentrations ([Gd‐DTPA]m) were measured 1 or 5 min after a bolus injection of Gd‐DTPA or immediately after the end of a constant infusion of Gd‐DTPA in a total of 35 dogs. It was found that within 5 min of a bolus injection [Gd‐DTPA]m is determined primarily by myocardial blood flow (MBF) and after about 10 min primarily by myocardial extracellular volumes (MECV). This study suggests that repeat, rapid (every 2–4 s) measurements of myocardial T1 relaxation rates following the bolus injection of Gd‐DTPA are required to calculate MBF (i.e., myocardial tissue perfusion) and MECV. © 1992 Academic Press, Inc.