Stronger, Faster Gradients

Another aspect of MRI hardware that has seen recent improvements are the magnetic gradients used for spatial encoding. The highly publicized NIH Human Connectome Project funded the construction of human 3T MRI scanners equipped with 100 mT/m and 300 mT/m maximum gradient strengths compared to the standard 40-70 mT/m gradients used in conventional clinical MRI scanners. This increased gradient strength provides the most significant gains for diffusion-weighted MRI (DW-MRI). DW-MRI uses the magnetic gradients to sensitize the MRI signal to the diffusive motion of water molecules and can be used to map white matter pathways in the brain. However, the advent of stronger magnetic gradients on clinical systems is opening the door to many other types of DW-MRI including new pulse sequences that can map new microstructural components including the size, shape and density of various tissue compartments. We are interested in developing pulse sequences that exploit the new domain provided by increased magnetic gradient strength.

In vivo characterization of axonal damage in multiple sclerosis using high-gradient diffusion magnetic resonance imaging

Huang S.Y., Tobyne S.M., Nummenmaa A., Witzel T., Wald L.L., McNab J.A., Kalwiter E.C.

Radiology, doi: 10.1148/radiol.2016151582.


Q-space Truncation and sampling diffusion spectrum imaging

Tian Q., Rokem A., Folkerth R.D., Edlow B.L., McNab J.A.

Magnetic Resonance in Medicine, 2016, doi: 10.1002/mrm.26071.


The Impact of Gradient Strength on In Vivo Diffusion MRI Estimates of Axon Diameter

Huang SY, Nummenmaa A, Witzel T, Duval T, Cohen-Adad J, Wald LL, McNab JA

NeuroImage, 2015, 106:464-72.


The Human Connectome Project and Beyond: Initial Applications of 300mT/m Gradients

McNab JA, Edlow BL, Witzel T, Huang SY, Bhat H, Heberlein K, Feiweier T, Liu K, Keil B, Cohen-Adad J, Tisdall MD, Folkerth RD, Kinney HC, Wald LL

NeuroImage, 2013, 80:234-45


Pushing the limits of in vivo diffusion MRI for the Human Connectome Project

Setsompop K, Kimmlingen R, Eberlein E, Witzel T, Cohen-Adad J, McNab JA, Keil B, Tisdall MD, Hoecht P, Dietz P, Cauley SF, Tountcheva V, Matschl V, Lenz VH, Heberlein K, Potthast A, Thein H, Van Horn J, Toga A, Schmitt F, Lehne D, Rosen BR, Wedeen V, Wald LL

NeuroImage, 2013, 80:220-33.


In Vivo Mapping of Human Spinal Cord Microstructure at 300 mT/m

Duval T, McNab JA, Setsompop K, Witzel T, Schneider T, Huang SY, Keil B, Klawiter EC, Wald LL, Cohen-Adad J

NeuroImage, 2015, 118:494-507.