Post Scanner Upgrade Problem

The CNI UHP scanner received a minor system upgrade on Tue. Aug 17 — Wed. Aug. 18.  The updates were to support two new multipurpose flexible AIR coil receive arrays.  You can read more about these coils here.

After the upgrade, GE confirmed the system met the “in spec” requirements that are normally used to confirm a system is ready for return to clinical service.  In addition, we ran our system stability QA that is important for fMRI scans and this also passed.

Unfortunately, Monday we discovered that certain MRI sequences now have substantial artifacts.  We resolved the issue Monday, with help from GE service and GE Headquarter’s Engineering ,by redoing the eddy current calibration procedures.  We determined that the original calibration files were corrupted during the upgrade.  We’re now on the alert for any further possible damage to these files, and GE is working to determine how their installation procedure corrupted these critical calibration files.

The sequences that are affected are few — so far, we’ve seen BRAVO T1-weighted scans, MR spectroscopy scans, and the Hyperband DTI scans being impacted.  If you used these sequences in this date range, please check to see if your data are corrupted.  In addition, we ask all users who collected data in the days after August 17th to check their data to make sure we have identifed all the problematic sequences.

The artifacts are not subtle.  Example images showing the artifacts we’ve seen are shown below.  We have not seen any problems with the fMRI sequences, either the stock EPI or Hyperband acquisitions.  So just visualizing your data with the Flywheel viewer should be enough.

If you do identify any unusable data, please contact Laima Baltusis regarding your scan and she will be able to arrange for no charge.  Sorry for the inconvenience!

The CNI Team