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Updated: Jul 4, 2025
Handheld Metal Detector Screening for Metallic Foreign Body Ingestion in Children
Published on: September 11, 2018
An unexpected ferromagnetic foreign body in a paediatric research participant undergoing 3T MRI
Katie Mckinnon1, Charlotte Jardine2, Gayle Barclay2
1Centre for Reproductive Health, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, UK.
Abstract:
Metallic foreign bodies (FBs) are a safety risk during MRI. Here, we describe a boy in early childhood with an unexpected ferromagnetic FB discovered during a research brain MRI. Safety precautions included written and oral safety screening checklists and visual check during a structured safety pause. During introduction to the scanner, he was lifted to look at the bore. Staff became aware of an object flying into the bore. The child reached for his ear, and a 5 mm diameter ball bearing was found in the bore. The child had no external injury. We have introduced a 0.1 T handheld magnet to check for metallic FBs not known to the parent. FBs are a common paediatric emergency department presentation, particularly in younger children or those with cognitive or behavioural problems. This case highlights the importance of safety screening in paediatric MRI scanning, along with its fallibility.
Insights
A child presented with an unexpected ferromagnetic foreign body during an MRI scan, highlighting potential safety risks. Enhanced screening measures, including a handheld magnet, are now used to prevent such incidents in pediatric patients.
Area of Science:
- Radiology
- Pediatric Imaging
- Medical Device Safety
Background:
- Metallic foreign bodies (FBs) pose significant safety risks during Magnetic Resonance Imaging (MRI) procedures.
- Standard safety protocols, including checklists and visual inspections, are crucial for preventing FB-related incidents in pediatric MRI.
Observation:
- An unexpected ferromagnetic FB, a 5mm ball bearing, was discovered in the MRI bore after a child reached for his ear during a research brain MRI.
- The child had no external injury, indicating the FB was not externally visible or recently inserted.
Findings:
- Despite rigorous safety screening, including written/oral checklists and a safety pause, a ferromagnetic FB entered the MRI scanner.
- The incident underscores the fallibility of current safety screening methods for detecting all metallic foreign bodies in pediatric MRI.
Implications:
- The case necessitates improved safety screening protocols for pediatric MRI, especially for young children or those with cognitive/behavioral challenges.
- Introduction of a 0.1 T handheld magnet is proposed as an additional screening tool to detect unknown metallic FBs.
- This highlights the critical need for continuous evaluation and enhancement of safety measures in advanced medical imaging environments.
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