A quick response a couple of month late, and probably obsolete.
For some IPG and electrode combinations from the Medtronic portfolio, new restrictions applies. Check Medtronic MRI webpage, http://www.mrisurescan.com
For a quick summary, check zrinzio et al 2011 (https://www.researchgate.net/profile/Ludvic_Zrinzo/publication/51569875_Clinical_Safety_of_Brain_Magnetic_Resonance_Imaging_with_Implanted_Deep_Brain_Stimulation_Hardware_Large_Case_Series_and_Review_of_the_Literature/links/02bfe50cc9e3130cae000000.pdf)
The SAR limit is quite hard. 0.4 W/kg is of course better (see Zrinzo link). However, new restrictions makes it possible to use multi-ch head coil, which is preferable for SNR issues. If you have a siemens system, the SPACE sequences could be a good options for 3D resolution T2 images. However, haven’t optimized these protocols at home yet. Think they have a low flip angle and low SAR/B1rms.
MPRAGE is always nice to have post-op. Good 3D image, with no SAR/B1rms issues.
Did a small survey, and B1rms 2 uT, correspond to about mean 0.4-0.5 W/kg, probably good to know.
Post-operative restrictions might be changing fast coming years, be sure to check the latest guidelines from the corresponding manufactures website.