Optimization of cardiac cine in the rat on a clinical 1.5-T MR system.

The overall goal was to study cardiovascular function in small animals using a clinical 1.5-T MR scanner optimizing a fast gradient-echo cine sequence to obtain high spatial and temporal resolution. Normal rat hearts (n = 9) were imaged using a 1.5-T MR scanner with a spiral fast gradient-echo (fast field echo for Philips scanners) sequence, three Cartesian fast gradient-echo (turbo field echo for Philips scanners) sequences with different in-plane resolution, and with and without flow compensation and half-Fourier acquisition. The hearts of four rats were then excised and left-ventricle mass was weighed. Inter- and intra-observer variability analysis was performed for magnetic resonance imaging (MRI) measurements. Half-Fourier acquisition with flow compensation gave the best sequence in terms of image quality, spatial as well as temporal resolution, and suppression of flow artifact. Ejection fraction was 71 +/- 4% with less than 5% inter- and intra-observer variability. A good correlation was found between MRI-calculated left-ventricular mass and wet weight. Using optimized sequences on a clinical 1.5-T MR scanner can provide accurate quantification of cardiac function in small animals and can promote cardiovascular research on small animals at 1.5-T.