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Although 7-T MRI has recently received approval for use in clinical patient care, there are distinct safety issues associated with this relatively high magnetic field. Forces on metallic implants and radiofrequency power deposition and heating are safety considerations at 7 T. Patient bioeffects such as vertigo, dizziness, false feelings of motion, nausea, nystagmus, magnetophosphenes, and electrogustatory effects are more common and potentially more pronounced at 7 T than at lower field strengths. Herein the authors review safety issues associated with 7-T MRI. The rationale for safety concerns at this field strength are discussed as well as potential approaches to mitigate risk to patients and health care professionals.

Gadolinium‐based contrast agents (GBCAs) are widely and routinely used to enhance the diagnostic performance of magnetic resonance imaging and magnetic resonance angiography examinations. T1 relaxivity (r1) is the measure of their ability to increase signal intensity in tissues and blood on T1‐weighted images at a given dose. Pharmaceutical companies have invested in the design and development of GBCAs with higher and higher T1 relaxivity values, and "high relaxivity" is a claim frequently used to promote GBCAs, with no clear definition of what "high relaxivity" means, or general concurrence about its clinical benefit. To understand whether higher relaxivity values translate into a material clinical benefit, well‐designed, and properly powered clinical studies are necessary, while mere in vitro measurements may be misleading. This systematic review of relevant peer‐reviewed literature provides high‐quality clinical evidence showing that a difference in relaxivity of at least 40% between two GBCAs results in superior diagnostic efficacy for the higher‐relaxivity agent when this is used at the same equimolar gadolinium dose as the lower‐relaxivity agent, or similar imaging performance when used at a lower dose. Either outcome clearly implies a relevant clinical benefit. Level of Evidence: 2 Technical Efficacy: Stage 3 [ABSTRACT FROM AUTHOR]

The article discusses the use of remote MR scanning (RMS) as a solution to the shortage of MR technologists skilled in execution expertise. RMS allows MR technologists to operate an MR scanner from a remote location, providing access to their talents even when physically distant. However, the current model of RMS only covers execution expertise and not safety expertise, which remains the responsibility of the site where the patient and MR scanner are located. The article proposes a solution where the RMS provider also provides MR safety expertise, allowing sites to rely on less expensive MR tech aides instead of locally retained MR technologists. This model requires clear delineation of responsibilities and liabilities between the RMS provider and the site. Overall, the article suggests that centralized access to both MR execution and safety expertise will increase access to safe and efficient MR study execution. [Extracted from the article]

Abstract Background Magnetic Resonance Imaging (MRI) of patients with implanted cardiac devices is currently considered hazardous due to potential for electromagnetic interference to the patient and pacemaker system. With approximately 60 million MRI scans performed worldwide per year, an estimated majority of pacemaker patients may develop an indication for an MRI during the lifetime of their pacemakers, suggesting that safe use of pacemakers in the MRI environment would be clinically valuable. A new pacing system (Medtronic EnRhythm MRI™ SureScan™ and CapSureFix MRI™ leads) has been designed and pre-clinically tested for safe use in the MRI environment. The EnRhythm MRI study is designed to confirm the safety and efficacy of this new pacing system. Methods The EnRhythm MRI study is a prospective, randomized controlled, unblinded clinical trial to confirm the safety and efficacy of MRI at 1.5 Tesla in patients implanted with a specifically designed pacemaker and lead system. The patients have standard indications for dual chamber pacemaker implantation. Successfully implanted patients are randomized in a 2:1 ratio to undergo MRI (MRI group) or to have no MRI scan (control group) at 9–12 weeks after pacemaker system implantation. Magnetic resonance (MR) scanning includes 14 head and lumbar scan sequences representing clinically relevant scans while maximizing the gradient slew rate up to 200 T/m/s, and/or the transmitted radiofrequency (RF) power up to SAR (specific absorption rate) levels of 2 W/kg body weight (upper limit of normal operating mode). Full interrogation of all device information and sensing and capture function are measured at device implantation, every follow-up and before and immediately after MRI in the MRI group and at the same time points in the control group. Complete pacemaker and lead evaluations are also done at one week and one month after the scan for the MRI and control group patients. The primary endpoint is safe and successful completion of the MRI scan as measured by freedom from both MRI-procedure related complications and clinically significant changes in the sensing and capture function of the leads. Results Results will be communicated after approximately 156 and 470 patients have completed 4 months of follow-up. Trial Registration ClinicalTrials.gov identifier: NCT00433654.

The need for a guidance document on MR safe practices arose from a growing awareness of the MR environment's potential risks and adverse event reports involving patients, equipment, and personnel. Initially published in 2002, the American College of Radiology White Paper on MR Safety established de facto industry standards for safe and responsible practices in clinical and research MR environments. The most recent version addresses new sources of risk of adverse events, increases awareness of dynamic MR environments, and recommends that those responsible for MR medical director safety undergo annual MR safety training. With regular updates to these guidelines, the latest MR safety concerns can be accounted for to ensure a safer MR environment where dangers are minimized. Level of Evidence: 1 Technical Efficacy Stage: 5 J. Magn. Reson. Imaging 2020;51:331-338. [ABSTRACT FROM AUTHOR]