Figure 3: MRI incidents reported by type over 22 years.
• Addition of an extra training requirement for MR operators to be fully aware of the relevant content of the MRI instructions for use. Following the equipment instructions is one of the key conditions of the MRI exemption.
Reported incident data We currently receive between 15-25 MRI incident reports a year. In comparison, in 2014 the agency received around 500 reports of issues with all other types of imaging equipment and approximately 14,000 reports for all devices. Figure 3 shows a breakdown of MRI incidents reported to us by type since 1993. Burns continue to be the
most frequently reported issue we see. Increasingly, we are seeing patients reporting MRI issues to us directly. In Appendix 4 of the guidance we have provided a list of incidents that should be reported to us. It also has a link to the MHRA's new reporting site:
https://yellowcard.mhra.gov.uk. The Yellow Card Scheme now supports the reporting of all suspected problems or incidents to all healthcare products, not just suspected side effects to medicines.
Emerging issues There have been a number of reports in the literature20
physical agents including noise, vibration and artificial optical radiation. The directive took guidance values from ICNIRP, which included a large safety factor below levels that
may cause adverse health effects, and used them as the limits for exposure. It was published in 2004 amid growing concern from the MRI community. Action in the UK by the charity Sense about Science16 formation of 'Alliance for MRI' in 200717
and the led to lobbying of Members of the European Parliament (MEPs)
and the European Commission against the directive. Research commissioned by the Health and Safety Executive18
had shown that anyone standing within about one metre of an MRI scanner while acquiring
images would exceed the exposure limits and that staff walking as slow as 1m/s close to an MRI scanner (approximately one metre) would exceed the limits, even when it was not in use. In 2007 the commission announced that implementation of the directive would be delayed for four years to allow further research into the potential impact. In 2012 an extra extension of 18 months was given to the implementation date. The final directive was published in June 201319
and includes a conditional exemption for the use of MRI
equipment for patients in the health sector. A second exemption is available to member states for ‘duly justified circumstances’. This may include veterinary MRI. The exemptions apply only to the exposure limit values. All other requirements such as performing risk assessments, protecting workers with implanted devices, provision of information and training will still apply. Our guidance has included minimal information about this as a non-binding practical guide will be published by the European Commission later this year, which will contain specific information for MRI. Some changes have been made to the guidance that are consistent within the text of the directive, specifically: • Introduction of the MR projectile zone to align with the relevant static field action level given in the Directive;
-45-
• The availability (especially paediatric) of spares, consumables and backup devices; • Training and familiarity of staff with the MR conditional device.
Gadolinium-containing contrast agents In 2010, the European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) recommended that further studies should be carried out on the long-term retention of gadolinium in human tissues released from gadolinium-containing contrast agents21 the CHMP meeting in January 201522
. Recent publications have shown that retention does occur23,24
. These studies were due to be discussed at and we
encourage sites to report to us on a Yellow Card any suspected adverse reactions, including nephrogenic systemic fibrosis, to gadolinium-containing contrast agents.
Future developments Scanning patients with contraindicated implants We have received many requests for advice to users on scanning patients with implants that are not MR
of patients suffering burns as a result of wearing
fabrics containing conductive fibres. These textiles are coated with silver nano-particles for an 'anti-odour' and 'antimicrobial' action, however when the coating is conductive, there is an increased risk of causing skin burns. This is not an issue if patients are changed into appropriate clothing provided by the MR unit, but staff should check for this when screening patients if there is no intention to change clothing. We have seen reports of delayed or cancelled scans where patients have come to the department with non-MRI conditional monitoring or infusion devices. Sites should have systems in place to ensure that MRI dedicated monitoring equipment can be used appropriately. This may be an issue at sites that have different makes and models in the department to outside the department. Particular issues are:
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68