From Journal of Neurosurgery Vol 117 - No. 1 - page 370-387.

MRI Protocol for GE Horizon for lead visualization...

Scanner - General Electric Horizon

T2-weighted FSE

  TR (msec) 3000

 TEeff (msec) 87

 matrix 384 − 256

 NEX 4

 slice thickness (mm) 2.0

 interleaved imaging

 time (min:sec) 10:48

volumetric gradient echo

  type of acquisition SPGR

 TR (msec) 36

 TE (msec) 8.0

 matrix 256 × 192

flip angle (°) 35

bandwidth (kHz) 15.6

NEX 0.75

slice thickness (mm) 1.5

imaging time (min:sec) 11:00

The above protocols were used to directly visualize DBS lead placement in 44 patients. The lead placement was very clear on the presented images. If you are still having problems getting the SAR threshold down to 0.1 W/kg. You have two parameters that you can manipulate, TR and Flip Angle. In the case of the FSE, Flip Angle is not manipulable since the refocusing pulses are fixed. You can reduce the number of refocusing pulses with a lengthening of the sequence in time.

In the case of the SPRG, you can reduce Flip Angle linearly to reduce SAR, in addtion to setting a longer TR. In both cases, longer scan times are the result but that is a small price to pay for safe scans for this type of information.

Article Citation - for the above answer.

Implantation of deep brain stimulators into subthalmic nucleus: technical approach and magnetic imaging—verified electrode locations

Philip A. Starr et. al. , Journal of Neurosurgery, July 2012, Vol 117, No. 1, pg 370-387.

Finally, A low SAR FSE scan can be implemented on you GE or Siemens scanner using modiified refocusing scheme for the 180 train. This may require some pulse sequence modification but can be on a standard scanner..

1. Sarkar, S. N. et al. Brain MR Imaging at Ultra-low Radiofrequency Power. Radiology 259, 550–557 (2011).