[Intl_DxMedPhys] Tests post gradient coil replacement for MRI

[Hardy, Peter A.]

Regarding testing gradient system after the installation of a new set.

As you know Siemens provides many tools to test the gradients including simple tests such as “Image Orientation” and more sophisticated tests such as Cross Term compensation to check that the Maxwell terms are compensated correctly. I have seen a case where the cables connected to the gradients were reversed and that would show up on the “Image Orientation” check. To ensure the gradients are performing correctly after this update I would run all the tests provided. However, before I started the tests, I would run the “Long Term Stability” test. This particular test ramps the gradients up and down to their maximum value. The point of it is to really shake the gradients to ensure everything is bolted down properly. Running this test should provide a good evaluation of how well the new gradients are attached to the magnet.

Many of the tests use a large, 30 cm diameter sphere. Before you start confirm that the sphere is pretty much filled. The diameter of the image of the sphere is used to fix the gradient calibration and so getting that coefficient correct will be important.


Peter Hardy, PhD
Associate Professor of Radiology, Neuroscience and Biomedical Engineering
Faculty, Division of Diagnostic & Nuclear Medical Physics
Department of Radiology
University of Kentucky College of Medicine
UK HealthCare
800 Rose Street, Room HX-307
Lexington, KY 40536-0293
Phone: (859) 323-2954
Email: peter.hardy at uky.edu<mailto:peter.hardy at uky.edu>


From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces+peter.hardy=uky.edu at lists.osu.edu> On Behalf Of Bob Kobistek via Intl_dxmedphys_wd_osu_list
Sent: Friday, July 11, 2025 3:01 PM
To: Steven Shea <steven.michael.shea at gmail.com>; intl_dxmedphys_wd_osu_list at lists.osu.edu
Subject: Re: [Intl_DxMedPhys] Tests post gradient coil replacement for MRI

CAUTION: External Sender

With the Siemens service tool, you can also run an eddy current compensation test. Robert J. Kobistek, MS, FACR, DABR, MRSE(MRSC™) Medical Physicist RJK Medical Physics, Inc. 440-463-7879 From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces@ lists. osu. edu>
With the Siemens service tool, you can also run an eddy current compensation test.


Robert J. Kobistek, MS, FACR, DABR, MRSE(MRSC™)
Medical Physicist
RJK Medical Physics, Inc.
440-463-7879

From: Intl_dxmedphys_wd_osu_list <intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list-bounces at lists.osu.edu>> On Behalf Of Steven Shea via Intl_dxmedphys_wd_osu_list
Sent: Thursday, July 10, 2025 12:52 PM
To: intl_dxmedphys_wd_osu_list at lists.osu.edu<mailto:intl_dxmedphys_wd_osu_list at lists.osu.edu>
Subject: [Intl_DxMedPhys] Tests post gradient coil replacement for MRI

Dear all, One of our MR systems is having the gradient coil replaced (thankfully under contract) and I will be conducting physics testing after the install & calibration. I will run the ACR phantom and perform all standard measurements. 
Dear all,

One of our MR systems is having the gradient coil replaced (thankfully under contract) and I will be conducting physics testing after the install & calibration. I will run the ACR phantom and perform all standard measurements. I also plan to look through the service tool (Siemens Magnetom Aera, I have a service key) to examine the different gradient calibrations & tests that should be done post install. I may also re-run the Siemens phantom shim (field map) test to verify field homogeneity since they will have ramped down & then ramped up the system.

For the MR experts out there -- would you run anything else? Any other test result to pay special attention to or focus on?

Thanks, Steve

Steven Shea, PhD
Associate Professor, MR Scientist
Department of Radiology & Medical Imaging. Loyola Medicine
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