In the last five to six decades, MRI scanning has gone from physics experiments in Nottingham University through to Nobel prize-winning work by Sir Peter Mansfield and Paul Lauterbur, to a ‘routine’ imaging modality with an estimated 60 million MRI scans being performed annually around the world. Despite the massive and significant developments over the years that we all take for granted when we request a scan from the radiology department, there are still some important provisos that we have to take into account – namely implants. Specifically for our specialty, cochlear and brainstem implants are often mentioned when requesting an MRI. However, within implant centres, patients will often be scanned with some adjustments made to allow the MRI to take place. This includes use of a head bandage, a splint over the implant and injection of local anaesthetic around the implant, particularly for non-MRI-compatible magnets. The Editors’ Choice paper reviews patients who require MRI scans with implants in-situ and concludes that scanning in a 1.5 Tesla MRI scanner is safe and tolerated. This is clearly well recognised in units that have an implant programme with buy-in from the radiologists and surgical teams, however the recognition that scans can be undertaken safely with minor steps taken will potentially allow patients to have an MRI for any reason in their local hospital without the need to travel to an alternative provider. This is something that radiology departments will need to build into their scan protocols, but this paper goes some way to providing evidence for this to be a safe practice. As always, thank you to all our reviewers for their hard work and contributions!
Nazia Munir and Hannah Cooper
Newer cochlear implant (CI) and auditory brainstem implant (ABI) models are now more compatible with magnetic resonance imaging (MRI) scanning because the internal magnets rotate, making it easier to scan patients with these auditory implant devices. However, there are still many patients with older style implants who require MRI scans. The advice with these older implants is to remove the magnet while scanning, but this has added risks of infection and device damage. Therefore, some centres scan with the magnet in situ, using a tight bandage with a hard splint over the implant magnet to prevent it from becoming displaced. Some patients report pain during scanning and, because of this, the procedure can be done with local anaesthetic. The team in Manchester examined factors which affected reports of pain with both styles of implants. Patients undergoing MRI scanning in a 1.5 T machine, were asked to report levels of pain and discomfort from one to five (one being no pain and five, extreme pain) at three intervals (before the procedure, during the head wrap and during scanning). The results show the majority of scans could be carried out without significant pain (an average score of two). In fact, discomfort increased during the head wrap procedure, rather than the scanning itself. Patients with the newer rotating magnet implants did not undergo a head wrap, but they too reported only a small increase in discomfort during scanning. It could not be determined whether anaesthesia helped, as very few patients opted for this. Interestingly, scanning below the head and cervical region was associated with increased levels of pain. Overall, the findings from the study support MRI scanning in a 1.5 T machine being a safe procedure with auditory implants.
