Contrast medium | MRT – Examination of the spine

Contrast medium

A contrast medium during an MRI examination of the back is always necessary if similarly dense tissues of the body are to be more clearly differentiated from each other and better distinguished in imaging (e.g. blood vessels and muscles). Contrast agents used in an MRI examination usually have a more indirect effect by altering (usually amplifying) the signals in the MRI image. Thus, they can be used, among other things, to better visualize pathological processes that often behave differently from the surrounding healthy tissue.

In addition, they can also be used to monitor the course of a disease or therapy.The contrast agents are usually administered via the vein during the MRI examination, so that the agent is distributed over the body’s blood system and, as a result, processes or tissues with a particularly good blood supply are shown more clearly (with more signal). For MRI examination of the back, the contrast agents Gadovist® (gadobuterol) for spinal imaging and Dotarem® (gadoteric acid) for spinal cord imaging are primarily used, both of which are based on the chemical element gadolinium. The areas reached by the gadolinium-containing contrast agents appear brighter in the imaging.

The contrast agents are excreted via the kidney or urine. The contrast media used in MRI examinations are generally well tolerated, so that hardly any side effects are known. Occasionally, there may be skin irritation at the injection site during administration, a tingling sensation, headaches and discomfort, or a sensation of heat or cold during contrast medium administration. However, when contrast media containing gadolinium are used in patients with severely impaired renal function, they can cause a rare disease called nephrogenic systemic fibrosis (NSF). This is a potentially life-threatening, systemic disease that causes abnormal growth of connective tissue in the skin, muscles and internal organs such as the lungs, heart, liver and diaphragm.

Risks

An MRI examination – in contrast to other imaging procedures using X-rays – does not involve any risks. Since only magnetic fields are used to generate images of the inside of the body, there is no radiation damage. Even the contrast medium that may be used does not contain iodine, so that here too there is no risk of serious side effects, such as a thyrotoxic crisis in patients with hyperthyroidism.

An allergic reaction to the contrast medium used is also rarely known. From time to time, mild symptoms such as skin irritation at the injection site, a tingling sensation, headache and discomfort, or a sensation of heat or cold may occur during contrast agent administration. Furthermore, there are also no known adverse effects of MRI examination in the unborn child, so it is considered an important possible imaging procedure during pregnancy.

Nevertheless, the indication should always be carefully established beforehand. The only danger posed by a magnetic resonance imaging device are metallic objects (e.g. coins, keys, hair clips, implants in the body, etc. ), which can be attracted by the magnetic field generated and thus cause injury or damage to the patient and the device (Caution: the magnetic field can cause implanted, vital pacemakers of patients to become inoperable).