This editorial refers to ‘Impact of cardiac magnetic resonance imaging on human lymphocyte DNA integrity,’† by M. Fiechter et al., on page 2340
Cardiac imaging is increasingly used to detect heart diseases and to guide therapy. Along with the increased use of cardiac imaging at clinics there is increased attention to the potential risks related to the methods used. Currently imaging tests using ultrasound or magnetic fields have been regarded safer alternatives compared with the tests utilizing ionizing radiation such as X-rays, computed tomography (CT), and nuclear imaging.1
However, various sources of risks related to, for example, exercise testing, pharmacological stressors, contrast agents, the imaging procedures themselves, invasive procedures, and cumulative ionizing radiation should all be taken into account collectively and ultimately weighed against the risks related to undetected disease or delayed diagnosis.
Magnetic resonance (MR) imaging relies on three different types of low-frequency electromagnetic waves: a static magnetic field, radiofrequency (RF) pulses, and gradient magnetic fields. Potential risks associated with MR may derive from the effects of each component on biological tissues and mainly on ferromagnetic objects. The latter is a well-known limitation of MR that can be avoided by appropriate patient selection, i.e. exclusion of patients with any metal object in their body. A strong static magnetic field as such is unlikely to cause significant adverse biological effects, although sporadic and transient sensations of nausea and dizziness have been reported. The RF energy delivered to the body may cause heating of tissues.2 The amount of RF energy delivered is defined as the specific absorption rate (SAR). To avoid significant heating, clinical scanners are set to operate within defined SAR ranges. A gradient magnetic field can stimulate nerves and muscles, occasionally causing discomfort,3 but current MR systems typically operate below nerve stimulation levels. However, cardiac MR …