Comparison of an 8-hannel and a 32-channel coil for high-resolution fMRI at 7 T

Multi-channel receive array rf-coils have become widely available for fMRI. The improved SNR and possibility of acquisition acceleration through parallel imaging are especially beneficial for high-resolution studies. In this study, an 8-channel and a 32-channel coil were compared in a high-resolution finger tapping fMRI experiment at 7 T. 1.3 mm³ resolution data acquired with the 32-channel coil provided higher image- and temporal SNR and yielded higher BOLD sensitivity measures, notably higher cluster sizes in MI/SI and increased z-scores, though not an increase in percent signal change. For sub-millimeter resolution fMRI data acquired with the 32-channel coil smaller clusters were found, though percent signal changes were significantly larger, due to reduced partial volume effects. These results demonstrate the utility of the use of an array coil with a large number of receive elements for high-resolution fMRI at ultra-high field.