MR Safety Week 2017
Unexpected Foreign Objects and MR Exams
Details about what transpired: The MRI department was requested to perform a non-urgent brain scan on an ambulant patient. The patient completed the screening form, indicating that s/he had suffered a previous metallic eye injury about 25 years ago when a small metal fragment had entered his/her eye for which s/he sought medical attention. S/He also indicated that s/he had an MRI of his/her brain approximately 5 years ago at another site.
The MRI technologist and radiologist reviewed the patient’s MRI safety information. The imaging report for the MRI brain scan was available for review and, aside from the age related-pathology there was no indication of a foreign body evident.
The MRI radiologist after reading the radiological report of his/her previous MRI, recommended it was safe to proceed with the scan and suggested that if the patient had undergone a previous MRI of his/her brain it was most likely that the other site would have performed safety screening of the patient prior to the scan. It was advised, for completeness, that the images should also be reviewed (if available) to be 100% sure. Review of the previous MRI scan demonstrated a large susceptibility artefact in the region of the right orbit. As a result, the initial decision to scan the patient was reversed, and it was decided not to go ahead with another MRI scan until the metallic fragment had been removed.
Remediation efforts by the site: The site reviewed this incident with respect to its screening policies. This incident was used as a lesson in reviewing prior imaging when ruling out the presence of orbital metallic foreign bodies.
Reported: The safety incident was recorded as a ‘near miss’ and reported as per local policies and procedures. The incident was reported by the radiologist to the other MRI site.
Lessons Learned: All imaging of the region, even if not specifically acquired to rule out the presence of metallic foreign bodies, should be re-reviewed by a radiologist when determining MRI safety clearance of orbits.
- Review head/orbital imaging when trying to rule out the presence of orbital metallic foreign bodies
- Just because a patient has had an MRI before, it doesn’t mean they are always safe to have another scan
- Review images as they are acquired! Look for artifacts. Such artifacts are not always documented in the MRI report.
Details about what transpired: The MRI department was requested to perform a non-urgent brain scan on an ambulant patient. When the patient presented for his/her scan, s/he completed the screening form and indicated that s/he had suffered a previous metallic eye injury to his/her left eye when welding. S/He stated that s/he had been referred previously by his/her clinician for an orbital X-ray, which was performed at another site to confirm that there was no metal remaining, so s/he could have an MRI scan. The radiologist report was obtained and reviewed by two MRI technologists as part of the safety screening process. The imaging report for the orbital X-ray confirmed that the patient had no metallic foreign bodies in the region. The patient was deemed safe for MRI and the examination was scheduled.
Part way through the localiser acquisition the MRI technologist noticed a susceptibility artefact in the right orbit and the sequence was stopped. The exam was halted and the radiologist was called to review the initial images. S/He agreed that no further images should be acquired as there was a substantial artefact that was likely due to a metal foreign body in the eye. It was decided that the exam should be ended and the patient should be slowly removed from the MRI scanner.
The radiologist explained the situation to the patient and performed a basic clinical assessment to confirm no obvious damage had been caused. S/he also suggested the patient be referred for further assessment so that the cause of the artefact could be established.
The MRI radiologist contacted the other hospital’s radiology department whom confirmed upon re-review of the x-ray that the there was a radio-opaque foreign body in the right eye, however, this was not commented on because the ‘referral specifically stated that there was a previous metal injury to the left eye’.
Remediation efforts by the site: The MRI technologists were deemed to have acted in accordance with site MRI safety policies. However, this incident was used as a lesson in reviewing all prior imaging when ruling out the presence of orbital metallic foreign bodies, and double checking the patient’s history – even if clearly stated by the referring clinician.
Reported: An incident/safety report was filed in accordance with local policies and procedures. The X-ray reporting radiologist was notified and the orbital X-ray report was modified.
Lessons Learned: The importance of reviewing all images as they are acquired for any artifacts. Technologists are responsible for identifying imaging artefacts, even during the MR examination, which could potentially impact patient safety and diagnosis. Further, they must act in a timely and appropriate manner to keep the patient safe.
- Review images as they are acquired! Look for artifacts!
- Understand different artifacts and their impact on patient safety.
- Review head/orbital imaging when trying to rule out the presence of orbital metallic foreign bodies.