Pitfalls in magnetic resonance imaging

Abstract

The constantly extending indication spectrum of magnetic resonance imaging (MRI) is a challenge for the anaesthesiologist, who is being increasingly more consulted for assistance during the examination. Due to the special technology of MRI the anaesthetic technique differs substantially from that in the operating theatre. In addition to the permanent strong magnetic field the intermittently used high frequency impulses are also a potential danger for the patient. Patients with metal implants (e.g. cardiac pacemaker) are particularly at risk. For the safe treatment of patients during MRI a special MRI compatible anaesthesia equipment is necessary. Unsuitable devices can lead to malfunctioning or to projectile effects (attracting ferromagnetic objects into the magnet) causing injury to the patients. This paper describes the MRI technology and the associated dangers for the patient as well as the characteristics of the anaesthetic techniques.

An unexpected ferromagnetic foreign body detected during emergency magnetic resonance imaging: a case report

“…MRI is a non-invasive, radiation-free diagnostic procedure [ 1 ]. A magnetic field with strength of 1.5 to 7 Tesla (T) (140 000 times the Earth’s magnetic field) is used to perform MRI clinically [ 3 ].…”

“…A magnetic field with strength of 1.5 to 7 Tesla (T) (140 000 times the Earth’s magnetic field) is used to perform MRI clinically [ 3 ]. The frequency of MRI scans in children has increased in the recent years due to significant technical improvements opening a wide range of diagnostic possibilities without ionizing radiation [ 1 ]. Depending on the diagnostic needs the scan takes about 15 to 90 minutes.…”

“…For optimum image quality the patients have to remain motionless. Younger children are mostly unable to cooperate adequately and therefore require sedation or even general anesthesia [ 1 ].…”

“…Because of the strong magnetic field no ferromagnetic materials can be used in the MRI scanner [ 2 ]. Metallic equipment is accelerated in the magnetic field [ 1 ]. Extreme caution has to be applied not to enter the scanner with any loose ferromagnetic material.…”

“…Magnetic resonance imaging (MRI) is a powerful non-invasive, radiation free diagnostic tool. The frequency of MRI examination especially in children who require sedation or anesthesia has increased in the recent years [ 1 ]. Here, the anesthesiologist has to be aware that ferromagnetic foreign bodies are a clear contraindication for a MRI scan due to potential relevant side effects [ 2 ].…”