Phase alignment of multiple surface coil data for reduced bandwidth and reconstruction requirements in volumetric MRI applications

Multiple element surface coils, or "phased array" multicoils, are often used volumetrically in magnetic resonance imaging (MRI) around a region of interest, such as the pelvis, head, abdomen or thorax to increase the image signal-to-noise ratio (S/N) when compared to the single channel "built-in" birdcage body coil. For applications which require high bandwidth such as echo-planar imaging or which perform continuous image acquisition such as real-time, or which acquire data with high temporal and spatial resolution such as 3D phase contrast and time-resolved 3D, the additional S/N gained from using multiple element surface coils is often critical for attaining adequate image quality. However, using the standard "sum of squares" technique can pose significant temporal limitations to the reconstruction, or pose significant demands on the available memory size, especially as requirements for reduced image acquisition time and improved spatial resolution increase. The authors show that multicoil phase alignment allows decreased technical requirements compared to the standard "sum of squares" method, while providing substantially improved S/N performance over a volumetric body coil.