Magnetic resonance imaging (MRI) of the abdomen (synonyms: Abdomen MRI; MRI abdomen; nuclear magnetic resonance imaging (NMR) of the abdomen) refers to a radiologic examination procedure in which a magnetic field is used to image the structures in the abdominal region containing the abdominal organs. 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 computed tomography (CT) are performed.
Indications (areas of application)
- Tumors in the abdomen (abdominal region) such as gastric carcinoma, pancreatic carcinoma (pancreas) or liver carcinoma, or renal tumors
- Gynecological tumors such as cervical carcinoma (cervical cancer) to exclude metastases.
- Inflammatory processes such as abscesses in the abdomen.
- Changes in the blood vessels such as atherosclerosis (arteriosclerosis, hardening of the arteries).
- Malformations in the abdomen and abdominal organs.
Contraindications
The usual contraindications apply to abdominal MRI as they do to any MRI examination:
- Cardiac pacemaker* (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.
* Some manufacturers now offer MRI-enabled pacemakers and ICDs that contain fewer metal components and have been shown to be safe in studies. In cases of severe renal insufficiency (kidney weakness) and existing pregnancy, contrast administration should be avoided.
The procedure
Magnetic resonance imaging is one of the noninvasive imaging procedures, meaning that it does not penetrate the body. By using the magnetic field, protons (primarily 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 abdomen is a very precise diagnostic procedure that is used today for many diseases and conditions.
Possible complications
Ferromagnetic metal bodies (including metallic makeup or tattoos) can lead to local heat generation and possibly cause paresthesia-like sensations (tingling). Allergic reactions (up to life-threatening, but only very rare anaphylactic shock) may occur due to contrast medium administration. The administration of a contrast medium containing gadolinium can also trigger nephrogenic systemic fibrosis in rare cases.
