Quantitative contrast-enhanced first-pass cardiac perfusion MRI at 3 tesla with accurate arterial input function and myocardial wall enhancement

Purpose:

To develop, and validate in vivo, a robust quantitative first‐pass perfusion cardiovascular MR (CMR) method with accurate arterial input function (AIF) and myocardial wall enhancement.

Materials and Methods:

A saturation‐recovery (SR) pulse sequence was modified to sequentially acquire multiple slices after a single nonselective saturation pulse at 3 Tesla. In each heartbeat, an AIF image is acquired in the aortic root with a short time delay (TD) (50 ms), followed by the acquisition of myocardial images with longer TD values (～150–400 ms). Longitudinal relaxation rates (R₁ = 1/T₁) were calculated using an ideal saturation recovery equation based on the Bloch equation, and corresponding gadolinium contrast concentrations were calculated assuming fast water exchange condition. The proposed method was validated against a reference multi‐point SR method by comparing their respective R₁ measurements in the blood and left ventricular myocardium, before and at multiple time‐points following contrast injections, in 7 volunteers.

Results:

R₁ measurements with the proposed method and reference multi‐point method were strongly correlated (r > 0.88, P < 10^?5) and in good agreement (mean difference ±1.96 standard deviation 0.131 ± 0.317 / 0.018 ± 0.140 s^?1 for blood/myocardium, respectively).

Conclusion:

The proposed quantitative first‐pass perfusion CMR method measured accurate R₁ values for quantification of AIF and myocardial wall contrast agent concentrations in 3 cardiac short‐axis slices, in a total acquisition time of 523 ms per heartbeat. J. Magn. Reson. Imaging 2011;. © 2011 Wiley‐Liss, Inc.