1. Introduction

Good news — after a lot of hard work over the weekend by the CNI staff, we are most of the way back to normal operation with our upgrade to GE’s RX28 release.  The significant accomplishments over the weekend include solving the issues with the research SMS sequences as well as the spiral fieldmap sequence.  These are all operational again and the new sequences are fully integrated with Flywheel.

There are a few minor changes to the user interface with this revision of the scanner operating system and we describe these below.

2. Coil Selection

The tab for receiver coil selection has changed in RX28. Instead of a list of connected coils and checkmarks for indicating which coils are selected to be used, the new interface shows each port of the coil connection and highlights which ports are active. By default the Nova 32ch Head coil will have both Port P1 and Port P2 selected (as shown in the screenshot below).

3. Product Hyperband Updates

The Hyperband sequences on RX28 now have built-in calibration scans. The calibration can be integrated into the prescan of each Hyperband scan, so there is no need to do a separate ASSET Calibration before the Hyperband scans. The integrated calibration scan is turned on by default (as shown in the screenshot). If it is turned off, a separate calibration scan (named “Cal: [original series description]“) will be created automatically once the Scan button is pressed.  The Hyperband BOLD sequence also no longer requires an even number of slices / band to be acquired so it will improve the efficiency of some prescriptions over that in RX27.  In addition, the slice timing is correctly calculated and stored in the DICOMs. We will work with the developer of the dcm2niix utility to extract these timings and save them to the accompanying JSON file – a fix was needed because the developer had disabled this feature for GE Hyperband DICOMs given the erroneous timing values that were present for versions earlier than RX28.

4. High-Order Shim

GE has switched from a spiral-based acquisition for their high-order shim (HOS) process to a 3D fast gradient echo acquisition.  Users will need to replace their existing HOS series in their protocols with the new HOS template.  This can be accessed by first choosing Add Task, then selecting the GE protocol library, choose Adult->Other in the lefthand tabs and then select the hosGE entry.  We suggest using the GE HOS FOV28 template as this will most likely include all of your subject’s brain while still providing reasonable resolution. This new 3D FGRE approach may have modest benefits when subjects have significant B0 inhomogeneity due to orthodontics or large sinuses.

5. Remaining Tasks

As mentioned in our previous post, we will try to get the new coil configuration format for the NOVA16 research coil next week.  We are also working with Gary Glover on getting his spiral in/out (sprlio) pulse sequence installed.  The “show” system in the corner of the CNI scan room near the large TV screen is still running RX27 but we hope to update to RX28 in the next couple of weeks.

Thanks for your patience as we worked through this upgrade. We expect future s/w upgrades to be simpler now that the UHP is more closely integrated into GE’s standard product software.  Please don’t hesitate to contact us if you have any questions when using the new system.

Thanks and stay safe!

The CNI Team