Magnetic resonance imaging (MRI) of the spine (synonyms: spinal MRI; MRI spine) – or also called nuclear magnetic resonance imaging (NMR) of the spine – refers to a radiological examination procedure in which a magnetic field is used to visualize the structures in the area of the spine.
MRI is now routinely used for many different indications, as it is a very informative diagnostic procedure. However, it is usually not the diagnostic tool of first choice. Prior to this, in many cases, other diagnostic procedures such as sonography (ultrasound) or a CT (computed tomography) scan are performed.
Indications (areas of application)
- Degenerative or inflammatory changes of the spine.
- Traumatic (accident) induced changes.
- Tumors in the area of the spine and spinal cord.
- Nucleus propulsus prolapse (herniated disc).
- Paraplegic syndrome
- Malformations in the area of the spine and spinal cord
- Metastasis search (search for daughter tumors).
Contraindications
The usual contraindications apply to spinal MRI as they do to any MRI examination:
- Cardiac pacemakers (with exceptions).
- Mechanical artificial heart valves (with exceptions).
- ICD (implanted defibrillator)
- Metallic foreign body in dangerous localization (e.g., in close proximity to vessels or eyeball)
- Other implants such as: Cochlear/ocular implant, implanted infusion pumps, vascular clips, Swan-Ganz catheters, epicardial wires, neurostimulators, etc.
Contrast administration should be avoided in cases of severe renal insufficiency (renal impairment) and existing pregnancy.
The procedure
Magnetic resonance imaging is one of the non-invasive imaging procedures, meaning that it does not penetrate the body. By using the magnetic field, protons (mainly hydrogen) are excited in the body to produce nuclear magnetic resonance. This is a change in the orientation of the particle due to a magnetic field. This is picked up as a signal by the coils placed around the body during the examination and sent to the computer, which calculates the exact image of the body region from the many measurements that take place during an examination. In these images, the differences in the shades of gray are thus caused by the distribution of hydrogen ions. In MRI, one can distinguish between different imaging techniques, such as T1-weighted and T2-weighted sequences. MRI provides very good visualization of soft tissue structures. A contrast agent can be administered for even better differentiation of tissue types. Thus, the radiologist can obtain even more detailed information about any disease processes that may be present through this examination.
The examination usually takes about half an hour and is performed with the patient lying down. During the examination, the patient is in a closed room in which there is a strong magnetic field. Since the MRI machine is relatively loud, headphones are placed on the patient.
Magnetic resonance imaging of the spine is a very precise diagnostic procedure that is used today for many diseases and complaints.
Possible complications
Ferromagnetic metal bodies (including metallic makeup or tattoos) can lead to local heat generation and possibly cause paresthesia-like sensations (tingling).
