Use of out of hours MRI in the Royal Victoria Hospital - a 6 month retrospective review.

Editor

Through the ongoing development of the Critical Care Centre, it is anticipated that the region's principal trauma receiving unit at the Royal Victoria Hospital will attain Level 1 Trauma Centre status. However an essential criterion for this is the provision of 24 hour access to MRI, as stipulated by the American College of Critical Care Medicine1. Out of hours MRI is currently provided as a time-limited, daily service on a consultant to consultant referral basis. Within the UK, it has been reported that only 32 out of 88 (36.3%) trauma units with MRI provide an out of hours service2.

We undertook a 6 month retrospective review of all patients requiring out of hours MRI between November 2007 and May 2008. Records were assessed for referral information, imaging result and clinical outcome. 74 patients in total had out of hours MRI. Of these, 48 were regarded as emergency (scan performed <24 hours from referral).

Of the 48 emergency requests, the majority came from neurosurgery (n=27) and neurology (n=14), with orthopaedics (n=5), general medicine (n=1) and A&E (n=1) making up the remainder. Figure 1 illustrates the categories of clinical referral, with the majority for either suspected cauda equina syndrome or cord compression.

Out of hours MRI had the greatest impact in suspected cauda equina syndrome, as all scan positive patients (n=5) had surgery on the day of scanning, and made good neurological recovery, with only 1 having ongoing pain at 6 month follow-up. Early surgery (<24hours) is felt to be of most benefit to those presenting with incomplete cauda equina syndrome3. However, it should be noted that suspected cauda equina syndrome contributed to 15% (11/74) of the total out of hours MRI caseload.

Of the 19 patients investigated for cord compression, 7 were confirmed on MRI. A further 2 patients were diagnosed with cord ischaemia. The remainder were either normal, had degenerative change or disc protrusion not causing compromise of the cord or nerve roots. 2 patients with confirmed cord compression were treated conservatively. Of those who had decompressive surgery, 2 were operated upon within 24 hours of their scan but neurological deficit persisted upon discharge.

It is anticipated that a modern, safe and comprehensive out of hours MRI service to Northern Ireland could be achieved with the 4 district general hospitals which have MRI capacity adopting an out of hours service similar to the current at the Royal Victoria Hospital, coupled with expansion of the Royal Victoria Hospital service to provide 24 hour access. Demand for out of hours MRI is anticipated to further increase with full implementation of NICE guidelines for stroke imaging and suspected metastatic cord compression.