Review Article Design, Operation, and Safety of Single-Room Interventional MRI Suites: Practical Experience From Two Centers Mark J. White, PhD, 1,2 * John S. Thornton, PhD, 1,2 David J. Hawkes, PhD, 3 Derek L.G. Hill, PhD, 4 Neil Kitchen, MD, 1,2 Laura Mancini, PhD, 1,2 Andrew W. McEvoy, MD, 1,2 Reza Razavi, MD, 5 Sally Wilson, MD, 1 Tarek Yousry, MD, PhD, 1,2 and Stephen F. Keevil, PhD 5 The design and operation of a facility in which a magnetic resonance imaging (MRI) scanner is incorporated into a room used for surgical or endovascular cardiac interven- tions presents several challenges. MR safety must be main- tained in the presence of a much wider variety of equipment than is found in a diagnostic unit, and of staff unfamiliar with the MRI environment, without compromis- ing the safety and practicality of the interventional proce- dure. Both the MR-guided cardiac interventional unit at Kings College London and the intraoperative imaging suite at the National Hospital for Neurology and Neurosurgery are single-room interventional facilities incorporating 1.5 T cylindrical-bore MRI scanners. The two units employ simi- lar strategies to maintain MR safety, both in original design and day-to-day operational workflows, and between them over a decade of incident-free practice has been accumulated. This article outlines these strategies, high- lighting both similarities and differences between the units, as well as some lessons learned and resulting proce- dural changes made in both units since installation. Key Words: MRI; safety; intraoperative imaging; neuro- surgery; endovascular intervention J. Magn. Reson. Imaging 2015;41:34–43. V C 2014 Wiley Periodicals, Inc. MAGNETIC RESONANCE IMAGING (MRI) is increas- ingly gaining acceptance for imaging during surgical and endovascular procedures (1,2). While the safe design and operation requirements for diagnostic MRI installations are well established (3–8), the use of MRI equipment in an interventional context presents addi- tional challenges (9). The requirements of the interven- tional procedure bring both additional staff and equipment—much of which will be MR Unsafe (10)— into the immediate vicinity of the magnet. This may exacerbate or create new MRI safety hazards, including ferromagnetic projectile hazards, MRI-associated radio- frequency (RF) heating of equipment on or inside the patient, electromagnetic interference (in both direc- tions) between the MRI scanner and other electronic equipment, and acoustic noise levels which may limit the ability of staff in the room to communicate or even risk damaging their hearing. All of these issues must be managed without compromising the safety or effec- tiveness of the interventional procedure itself. Facilities for “intraoperative MRI” or “interventional MRI” (both abbreviated here as iMRI) have comprised a very wide range of installation types, including moveable low-field (<0.5 T) MRI systems used in con- ventional operating theatres (11) and layouts config- ured either to move the patient into a separate scanner room (12,13) or to bring in the scanner from an adjoining room or alcove (14) at multiple points during the intervention. In this article, discussion is limited to our experience of single-room layouts where a conventional cylindrical-bore 1.5 T scanner provides image guidance for interventions taking place in the same room, either within or outside the magnet bore. We describe the design choices, safety policies, and operational procedures developed at two installations of this type, located respectively at the Guy’s Hospital campus of King’s College London (KCL) and at the National Hospital for Neurology and Neurosurgery (NHNN), a division of UCLH NHS Foundation Trust. The facilities meet different clinical needs—endovas- cular cardiac interventions at KCL, and image-guided 1 National Hospital for Neurology and Neurosurgery, Queen Square, London, UK. 2 UCL Institute of Neurology, Queen Square, London, UK. 3 UCL Centre for Medical Image Computing, London, UK. 4 IXICO, London, UK. 5 Kings College London, London, UK. White, Thornton, Kitchen, Mancini, McEvoy, Wilson, and Yousry have received institutional grants from the UCL/UCLH NIHR Comprehen- sive Biomedical Research Centre. Razavi, Hill, Hawkes, and Keevil have received institutional grants from the EPSRC and from Philips Healthcare. Hawkes has also received institutional funding from the UK HEFCE Joint Research Equipment Initiative. *Address reprint requests to: Dr. Mark White, Neuroradiology Depart- ment (Box 65), National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, UK. E-mail: mark.white@ucl.ac.uk Received October 29, 2013; Accepted January 10, 2014. DOI 10.1002/jmri.24577 View this article online at wileyonlinelibrary.com. JOURNAL OF MAGNETIC RESONANCE IMAGING 41:34–43 (2015) V C 2014 Wiley Periodicals, Inc. 34