Applying the principles of the WU-Minn Young Adult study, the HCP consortium ran the Lifespan HCP Pilot Project to collect multimodal imaging data across the lifespan (ages 4-75, in 6 age bands), using scanners that differ in field strength (3T, 7T) and maximum gradient strength (70-100 mT/m). The scanning protocols used are similar to those for the WU-Minn Young Adult HCP, except shorter in duration.
The objectives were (i) to enable estimates of effect sizes for identifying group differences across the lifespan and (ii) to enable comparisons across scanner platforms, including data from the MGH Lifespan Pilot. The initial data released in August 2014 includes unprocessed Phase 1a image data.
The WU-Minn Lifespan team acquired imaging and behavioral data from six age groups (4-6, 8-9, 14-15, 25-35, 45-55, 65-75 years old) spanning a variety of ages of interest to a wide range of investigators.
Imaging data were acquired on three MRI scanners:
For each scanner, identical imaging parameters (pulse sequences and scan durations) were used for each modality across all age groups, except for the youngest (see below).
These parameters are similar but not identical to those acquired in the main (young adult) HCP; the main difference is a reduced scan time owing to tolerance limits for younger and older age groups.
The youngest group (4-6 years) were scanned only at WashU, using a customized pediatric head coil and a protocol optimized for that age range.
Behavioral data similar to that in the main HCP were acquired from all Lifespan Pilot subjects studied at WashU.
In Phase 1a, we evaluated the feasibility of a proposed protocol for scanning multiple age ranges to aid in determining a final protocol for each scanner. Phase 1a was conducted only at WashU.
Phase 1b involved a fixed protocol to acquire sufficient data to estimate effect sizes in each age range and for each scanner.
Head motion during scanning introduces undesirable artifacts for all MR modalities. This is of particular concern for the Lifespan pilot because head motion in children and older adults typically exceeds that in young adults.
Using volumetric navigators for prospective motion correction (Siemens “WIP 711”; Tisdall et al., 2012) is a potentially attractive way to compensate for head movement in T1w scans (by real-time detection and frame/data reacquisition). For the WashU subjects, we are acquiring both a traditional MPRAGE T1w scan and a vNAV T1w scan in order to ascertain how much benefit this provides. vNAV pulse sequences are not yet available for T2w scans or for the Prisma or 7T platforms.
Each structural scan (T1w and T2w) is rated on a 4-point scale (1=poor, 2=fair, 3=good, 4=excellent) using criteria developed for the main HCP.
Structural scans rated 3 or 4 for both T1w and T2w in the same session are automatically released. If this criterion is not met, scans rated 2 are further inspected and released if considered acceptable. (In contrast, only scan pairs with both rated 3 or 4 are released by the main HCP.)
For Lifespan data acquired on the WU-Minn 3T Connectom scanner, both 'unprocessed' data, and data corrected for gradient nonlinearities are included in the data release.
If you intend to use the unprocessed data, the gradient unwarping code specific to the WU-Minn 3T Connectom scanner is available at github.com/ksubramz (Jovicich et al., 2006). The gradient field nonlinearity coefficients for the Connectom scanner are considered by Siemens to be proprietary information. To request access to these coefficients, please contact your Siemens collaboration manager or email Dingxin Wang at email@example.com.
Tisdall MD, Hess AT, Reuter M, Meintjes EM, Fischl B, van der Kouwe AJ (2012) Volumetric navigators for prospective motion correction and selective reacquisition in neuroanatomical MRI. Magn Reson Med. 68:389-99. PMID: 22213578
An open-access dataset of HCP Lifespan pilot imaging data has been released on ConnectomeDB. Phase1a data is released (August 2014) as a single package including unprocessed and gradient nonlinearity-corrected data from all Phase1a subjects.
Due to the competing priorities of the end of the HCP Young Adult Study and the beginning of the funded HCP Development and HCP Aging Studies, we have put the release of Lifespan Pilot Phase 1b data and minimally preprocessed data from both phases on hold.