Magnetic resonance imaging: advantages and disadvantages

Advantages of magnetic resonance imaging

• no exposure to radiation  (compared to X-ray and computed tomography)
• according to current knowledge, the examination has  no lasting side effects
• certain structures, especially soft tissue such as nerves or the brain, can be displayed better (or at all).
• Tumors,  inflammations  and injuries are particularly easy to see

Disadvantages of MRI

• Costs:  A major disadvantage is the cost of both acquisition and operation.
• Artifacts and resolution:  Compared to the CT image, artefacts occur more frequently, technically caused structures that overlay the actual image and can lead to misjudgments. The resolution of the images is limited to about one millimeter.
• Metal:  Another disadvantage is that metal on or in the body (e.g. coins, bunch of keys, metal splinters, vascular clips, intrauterine device) can cause image disturbances or possibly heat up or shift, so it can be dangerous for the patient. However, the implants used today, such as artificial hip joints, no longer pose a problem; Contraindications are cochlear implants, implanted insulin pumps and the first trimester of pregnancy. MRI is also not recommended for large tattoos, as the color pigments contain metal. Pacemaker wearers have not previously been examined by MRI, but some large centers have recently begun to offer this.
• Narrow tube:  The narrow tube in whole-body tomographs, which has an average diameter of 60 cm and is around 160 cm long, is very uncomfortable for many patients. In individual cases, the examination is therefore carried out with sedatives or even under  anesthesia  . With the smaller devices, which can also be used to examine individual body parts, this is unnecessary.
• Risk of blurring and volume:  Keeping still is very important – a particular challenge given the loud knocking noises of the device. Hearing protection is therefore obligatory, and  sleeping pills may also be  necessary, especially for children.
• Allergy :  For some questions or special examinations (e.g. MR angiography = MRA), a contrast medium is also given, which in turn can cause allergic reactions in individual cases.
• Duration:  And last but not least, the investigation – despite all developments – is still taking a relatively long time.

outlook

Research into expanding the areas of application and minimizing the disadvantages is far from over. They range from  more powerful magnetic fields  and more  sensitive sensors  to measuring other atomic nuclei to make special structures such as cancerous growths more visible.

The development of MRT procedures not only for diagnostics, but also for research into causes, preparation for operations and therapy control are progressing steadily. In this way, metabolic processes such as  brain activity can be  measured (functional MRT =  fMRT ) – now even in real time.

Significance for brain research

A great potential for gaining new insights, especially in the current areas of brain research and neuropsychiatry, for example in diseases such as  schizophrenia .

And such insights into our inner worlds can even be interesting for other areas – for example, the advertising industry hopes for useful statements as to when which brain regions  react to advertising stimuli and how.