A receive insert for non-human primate functional MPI (fMPI)

We designed and built a receive gradiometer coil for non-human primate (NHP) fMPI studies. The coil was integrated and tested within our human-size brain MPI system. We demonstrate the imaging resolution and sensitivity expected in NHP studies using a dilusion series sensitivity measurement (120 µg to 23 ng iron mass) and a NHP-brain-sized phantom with an iron concentration of 62.5 µg/ml, below the level expected in arterial blood in MPI (143.0 µg/ml). Using 6 mT drive amplitudes and producing one 12.8 cm field-of-view image every 4.7 seconds resulted in a detection limit (SNR = 1) of 19.5 ng of iron in 2D imaging and good image quality. This would correspond to a contrast-to-noise ratio (CNR) of ∼20 for a 25% change of cerebral blood volume (CBV) following activation in a 6 mm isotropic voxel. These promising preliminary sensitivity levels encourage the pursuit of the first in vivo brain function MPI experiments in primates.