Clarissa Zimmerman Cooley1,2, Jason Stockmann1,2, and Lawrence L Wald1,2,3
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Harvard–MIT Division of Health Sciences and Technology, Cambridge, MA, United States
1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Harvard–MIT Division of Health Sciences and Technology, Cambridge, MA, United States
We present a portable MRI scanner for brain
imaging using a 35 kg Halbach bulb magnet and external gradient coils. In
vivo human T2-weighted images are demonstrated.
Prototype halbach-bulb scanner is shown. The
order of the components from innermost to outermost are: RF Tx/Rx coil, B0 shim magnets, RF shield,
main B0 magnet, and gradient coils. During the scan, the patient’s head rest on
the RF coil. The rest of the system (B0 magnet, RF shield, and gradient coils)
is on rails and slides over the coil and patient.
3D T2-weighted images of
the brain in a healthy adult volunteer.
3D RARE
sequence, resolution
= 1.5mm x 2.8mm x 7mm,TR/TEeff
=3000ms/134ms,
acquisition time = 25 min (6 averages).
A)
Images reconstructed assuming linear encoding fields resulting in distortion,
b) Images reconstructed using the generalized encoding method employing the
measured fieldmaps in (c).
C) combined measured B0 variation map and readout gradient maps for image
reconstruction.