Philips Intera: image artifacts and scan aborts on gradient-heavy sequences
What happened
Artifacts appeared on images acquired with heavily gradient-loaded programs, and scans periodically aborted as if the patient was moving the table, although the table was not actually moving.
What was checked
- Reported in the case: the engineers spent about two weeks ruling out gradient-related artifact sources before localizing the fault to the patient table.
- In this case the fault was traced to the connector of the wire-pinch protection sensor (a plate with microswitches) on the table, by reproducing the artifacts on gradient-heavy programs and monitoring that circuit.
Cause
The engineers found a poor contact in the connector of the wire-pinch protection sensor plate: under the vibration of strong gradients the contact dropped out, producing false table-motion signals and image artifacts.
What was done
The engineers disassembled the connector, cleaned the contacts and re-tensioned them for reliable contact pressure; after that the artifacts and scan aborts disappeared completely.
Safety
The static magnetic field of an MR system is always on: keep ferromagnetic tools and loose parts away from the bore when working on the table, and complete an electrical safety check before returning the scanner to use.
Lesson: An intermittent contact in a table safety sensor can mimic patient motion and gradient artifacts, so with such symptoms it pays to check vibration-sensitive connectors on the patient table early.
Covered in the course: MRI Service — Level 2: Fault-Finding →
Written from an anonymised case shared by service engineers. It is not a manufacturer instruction and grants no authorisation. Independent note; names are trademarks of their owners.