Global measurement of the myocardial perfusion index: application to the assessment of the incomplete Gd- DTPA clearance in rest/stress studies of cardiac perfusion

present a method for the acquisition and analysis of a global myocardial Gd-DTPA uptake using a model-independent approach for pixel-by-pixel mapping of the perfusion index (PI). Quantitative analysis of PI measurements was performed by applying a histogram based method. This method was applied to measure the influence of residual Gd-DTPA concentration in the blood plasma and myocardium on the MRI measurement of Gd-DTPA kinetics when a second injection of Gd-DTPA is administered in rest/stress perfusion studies. Methods Acquisition sequence: A T1 weighted gradient echo sequence with a segmented EPI readout (TFE-EPI) was implemented on a 1.5 Tesla GYROSCAN ACS NT clinical MR imaging system (Philips Medical Systems). T1 contrast is achieved by the use of a saturation pulse applied after the R wave. Six short axis slices were acquired over two heartbeats (for heart rates lower than 150 bps). The total acquisition time for each slice was 90ms (9 RF pulses TR 8.7ms, TE 3.7ms,