Potential impact of 32 channel receiver coil technology on functional magnetic resonance imaging

Purpose: Using finger tapping as the standard motor task for functional magnetic resonance imaging (fMRI), we aimed to test the potential of a 32 channel coil for performing fMRI compared to a standard 8 channel coil.

Methods: Brain activations were investigated in 14 healthy right-handed subjects performing finger tapping with the right index finger during two experimental sessions, one with the 8 channel coil and one with the 32 channel coil. The order of both sessions was pseudorandomized. The experiment was carried out based on a conventional block design and functional imaging data were analyzed using SPM5. Additionally signal to noise and contrast to noise ratios were compared.

Results: During both sessions activation on an FWE-corrected level was observed in the motor cortex (precentral gyrus). A paired t-test comparing the effects of finger tapping with the contrast „8 channel coil >32 channel coil“ revealed no activations, whereas the contrast „32 channel coil >8 channel coil“ revealed activations in the left hippocampus, left middle temporal gyrus, left middle and superior frontal gyrus, left and right cerebellum, left and right temporal pole, left fusiform gyrus, and left precentral gyrus (p<0.001 uncorrected for whole brain volume).

Conclusion: We demonstrated that the 32 channel coil indicated higher contrast to noise ratios, and thus a more significant brain activation compared to the 8 channel coil. This technology has a potential impact on fMRI as well as on studies employing dynamic signal changes e.g. contrast enhanced angiography or perfusion studies.