Cardiac magnetic resonance parallel imaging at 3.0 Tesla: technical feasibility and advantages

To quantify changes in signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), specific absorption rate (SAR), RF power deposition, and imaging time in cardiac magnetic resonance imaging with and without the application of parallel imaging at 1.5 T and 3.0 T.

Phantom and volunteer data were acquired at 1.5 T and 3.0 T with and without parallel imaging.

Doubling field strength increased phantom SNR by a factor of 1.83. In volunteer data, SNR and CNR values increased by factors of 1.86 and 1.35, respectively. Parallel imaging (reduction factor = 2) decreased phantom SNR by a factor of 1.84 and 2.07 when compared to the full acquisition at 1.5 T and 3.0 T, respectively. In volunteers, SNR and CNR decreased by factors of 2.65 and 2.05 at 1.5 T and 1.99 and 1.75 at 3.0 T, respectively. Doubling the field strength produces a nine-fold increase in SAR (0.0751 to 0.674 W/kg). Parallel imaging reduced the total RF power deposition by a factor of two at both field strengths.

Parallel imaging decreases total scan time at the expense of SNR and CNR. These losses are compensated at higher field strengths. Parallel imaging is effective at reducing total power deposition by reducing total scan time.