Calls to improve MRI safety

A ferromagnetic object taken into the MRI magnet’s stray field can be pulled into the magnet’s core at high speed, causing serious injury, damage and downtime. Serious incidents involving this phenomenon, known as the ‘projectile effect’, have been reported by numerous medical institutions. Many incidents have been documented involving such objects as gas cylinders, chairs, respirators, IV poles and smaller objects. Such occurrences can result in the loss of imaging time due to repairs, and/or injury to patients or staff. In their paper, Magnetic resonance imaging safety issues including an analysis of recorded incidents within the UK, JP De Wilde and D Grainger et al (2007) concluded that the main safety incidents included ‘accidents’ where safe working practice was not followed correctly – such as bringing ferromagnetic objects into the scan room. In such incidents, any such device will be subject to the attraction and rotational forces from the static magnetic field. In 2004, Colletti reported an incident where the wrong type of oxygen cylinder was brought into the scanner room while a critically ill patient was being monitored. As the radiographers were removing the patient from the scanner, the patient’s oxygen levels dropped and an 80 kg oxygen cylinder was wheeled in by the patient’s physician. In this instance only the magnet itself was damaged. However, a similar incident in 2001 resulted in the death of a young boy when he was struck on the head. The National Patient Safety Agency in January 2007 reported, in its Patient Safety Bulletin, that projectiles from patient safety incidents included objects as diverse as ‘a mirror, tweezers, keys, a sprung pillow, monitor and syringe driver’. The most comprehensive peerreviewed paper that quantifies projectile accident risks (Chaljub, Kramer et al) identified the rate of major projectile accidents as increasing – with some 52% of hospitals reporting accidents or incidents. However, it is widely accepted that most incidents go unreported. It is estimated that reporting in the US accounts for only 1% to 10% of all accidents occurring in the MRI suite. Of the range of incidents reported by the MHRA in the UK, the second largest single group were projectile incidents and significantly over 22% of these involved items labelled as ‘MRI Safe’.

Costs of an incident

Costs associated with an MRI accident can vary irrespective of any potential consequence resulting from injury or harm to patient or staff. Typical costs of an MRI accident could be all or a combination of the following typical elements: