Components of the Human Connectome Project
Cutting-edge MRI Hardware Technology. The HCP has developed customized MRI equipment to comfortably image the large subject population. All subjects in the main cohort are being scanned on a dedicated 3 Tesla (3T) scanner optimized for HARDI (High Angular Resolution Diffusion Imaging) and for R-fMRI (Resting-state fMRI), and T-fMRI (task-evoked fMRI). A subset of subjects will also be scanned using 7T MRI and, possibly, an additional set of subjects at 10.5T.
Gradient Hardware. The dedicated 3T scanner has been built with a customized gradient set capable of approximately double the maximum gradient strength (70mT/m to 100mT/m) of a standard scanner (40mT/m) to provide the highest performance on a 3T scanner that is safe and reliable using current technology. Given its clinical design, it will provide high-throughput capability, high reliability, and an excellent reference dataset for future connectome studies carried out at various institutions that have a similar commercial 3T scanner. The 7T scanner is equipped with a head gradient insert capable of 80mT/m with nearly double the slew rate as is typically achieved with conventional body gradients, such as those that will be used on the 3T.
Multichannel RF coil for Parallel Imaging. Parallel imaging performance, whether used in the conventional way in the phase encode direction (e.g. SENSE or GRAPPA), or multiplexing slice encoding is dependent on multi-channel coils. A new RF coil array designed for 3T was developed and optimized to maximize the parallel imaging performance as well as signal-to-noise ratio (SNR).
MRI Scanners. Scanning at 7T is challenging because the technology available on commercial systems is less developed and less suitable for routine use than a 3T system. However, 7T provides better signal-to-noise ratio, better parallel imaging, and significantly higher functional contrast and spatial specificity. Our preliminary data suggests that this can yield more accurate and sensitive anatomical and functional connectivity data. By conducting 7T scanning at the University of Minnesota we will leverage the extensive experience of this group that pioneered 7T human imaging. Additionally, we will benefit from their second 7T scanner (a new generation and optimized instrument installed in 2010) and a pioneering 10.5T scanner, which will be constructed and operational by 2012 to produce even higher SNR images with commensurate increases in functional contrast to noise ratios. Having higher field scans performed on individuals also scanned at 3T will allow higher-resolution data to constrain and better interpret the 3T data.