The quantification of cardiac perfusion requires gadolinium first-pass CMR images. As of now, full quantification is only supported for specific Philips MR acquisition sequences and dedicated reconstructions, which can be obtained from GyroTools (www.gyrotools.com). The MR acquisitions required for fully quantitative CMR include:
▪Dynamic gadolinium first-pass scan: A 3D k-t PCA sequence which is able to acquire volumetric contrast images covering the entire left ventricle within a breath hold of 20 seconds. Taking into account ECG triggers, contrast images can be reconstructed which are practically devoid of motion. It is recommended setting ECG-triggering to end-systole. This minimizes heart motion and the myocardium is thickest due to the contraction. The images should be acquired in short axis orientation and loaded such that the apex appears to the left (first slice).
▪B1 scan (COCA): A volumetric sequence allowing the assessment of the B1 field inhomogeneity of the surface coils. This scan can be omitted if the B1 field across the heart is sufficiently homogeneous.
▪T1 scan: A single-slice sequence measuring the global T1 relaxation time in the blood pool and the myocardium in a mid-ventricular slice using four time points. It is applied for converting the MR signal to contrast agent concentration. This scan can be omitted if the relation between contrast agent concentration and MR signal is linear.
Only a partial analysis can be performed with the images from classic gadolinium first-pass CMR sequences available on current clinical scanners. These acquisitions are longer, subject to breathing motion, and provide only 3 slice images at representative levels of the left ventricle.