Coil Array Compression in Coronary MRA

Introduction: In coronary MRA signal-to-noise ratio (SNR) is of primary concern as it limits the achievable spatial resolution for a given, tolerable scan time. One approach to increase the base SNR has been the design and application of multi-element coil arrays featuring up to 128 independent receive channels [1]. With 32element coil arrays becoming standard for cardiac imaging [2], attention has been drawn to processing data from large arrays with its associated increased memory consumption and computational load. Coil array compression [3, 4] is a new technique for reducing the amount of data being processed by using a suitable linear combination of the physical coil elements creating a reduced set of virtual coils. The combination matrix is found by optimizing the SNR in a target region of interest. It has been demonstrated that array compression significantly outperforms simple coil selection in which fewer physical coils are utilized [3]. While initial simulation and in-vivo work has proven the efficiency of array compression, its applicability to coronary imaging remains to be evaluated. In this work array compression is investigated for different compression factors applied to data from a 32-channel array. Relative SNR losses on the right coronary artery (RCA) and the left anterior descending artery (LAD) were evaluated in 10 healthy volunteers.