Safety considerations in MR imaging.

Abstract

The authors identify eight areas of potential safety concern during clinical magnetic resonance (MR) imaging. These include (a) biologic effects of the static magnetic field; (b) ferromagnetic attractive "projectile" effects of the static magnetic field; (c) potential effects of the relatively slowly time-varying magnetic field gradients; (d) effects of the rapidly varying radio-frequency (RF) magnetic fields, including RF power deposition concerns; (e) auditory considerations from noise caused by the rapidly pulsed magnetic field gradients; (f) safety considerations concerning superconductive systems, including quenches, use of cryogens, and cryogen storage and handling; (g) psychological effects, such as claustrophobia and anxiety induced because of the examination; and (h) possible effects of the intravenous use of the MR contrast agent gadopentetate dimeglumine. The concerns in each of these categories are elaborated upon, and the available data are presented to clarify their status.

Guidelines for Monitoring and Management of Pediatric Patients During and After Sedation for Diagnostic and Therapeutic Procedures: An Update

“…Electrocardiogram monitoring during MRI has been associated with thermal injury; special MRI-compatible ECG pads are essential to allow safe monitoring. [181][182][183][184] Expired carbon dioxide monitoring is strongly encouraged in this setting.…”

Auditory Noise Associated With MR Procedures: A Review

“…The problems associated with acoustic noise for patients and healthcare workers include simple annoyance, difficulties in verbal communication, heightened anxiety, temporary hearing loss, and potential permanent hearing impairment (1)(2)(3)(4)(5)(6)(7)(8). Acoustic noise may pose a particular hazard to specific patient groups who may be at increased risk.…”

Diagnostic imaging of renal artery stenosis

“…It was known to induce acute anxiety symptoms in up to 10% of people requiring abortion of scanning in approximately 1%. 69,70 Improvements in magnet design have reduced these problems but it is still necessary for the patient to lie still during the examination. Patients with pacemakers and certain ferromagnetic aneurysm/haemostatic clips, valve replacements and metallic intra-orbital foreign bodies are unsuitable for MRI.…”

“…Patients with pacemakers and certain ferromagnetic aneurysm/haemostatic clips, valve replacements and metallic intra-orbital foreign bodies are unsuitable for MRI. 70,71 There are two basic MRA methods known as timeof-flight (TOF) MRA and phase-contrast (PC) MRA. These are both flow sensitive techniques and can be acquired in either 2-D or 3-D formats.…”

“…The incidence of patient reactions is much lower than with conventional iodinated contrast media but they may rarely be associated with generalised warmth and local pain and there have been case reports of headache, vomiting and anaphylactoid reaction. 70 Various MRA sequences have been evaluated. In comparison with intra-arterial DSA the 2-D TOF sequence has reported sensitivities and specificities of 91-100% and 92-94% respectively for diagnosis of greater than 50% stenosis of the proximal portions of the main renal arteries.…”