MR Enterography is a non-invasive imaging method of examining the intestine throughout, in which electromagnetic pulses emitted by hydrogen atoms in a strong magnetic field are used to obtain images and their volumetric reconstruction. It is used as a screening method for detecting primary tumors and metastatic processes, intestinal polyps. It is of diagnostic value in identifying abnormalities of the gastrointestinal tract, foreign bodies, diverticula, intestinal obstruction, and the source of bleeding. In order to improve the visualization of intestinal loops, per os contrast or double contrast enhancement (oral and intravenous contrast) can be used.
MR Enterography is rarely used in diagnostics. The main indication is the search for neoplasms, clarifying their location and the boundaries of the pathological process for the purpose of further surgical treatment. The study allows not only to reliably detect the tumor, but also to determine its internal structure, to assess vascularization. In addition, the images can visualize hard-to-reach places, such as the mesentery root and basal lymph nodes, which may contain neoplasia metastases. Benign formations, polyps and intestinal diverticula are also detected by scanning. For the diagnosis of inflammatory diseases, MR enterography is prescribed when the process is localized in the small intestine or there are contraindications to colon contrast.
MRI examination is used in the diagnosis of intestinal obstruction, and may also be required to detect foreign bodies of non-metallic nature. Another indication for the procedure is intestinal bleeding and intestinal infarctions. The examination is prescribed to monitor the effectiveness of surgical treatment of tumors. MR enterography is required in cases where there are contraindications to the use of other diagnostic methods, for example, if you are allergic to iodine-containing contrast agents used during CT of the abdominal cavity.
Examination is contraindicated in the presence of any metal-containing elements in the patient’s body, since vascular clamps, staples, traumatological and orthopedic metal structures, as well as metal fragments in the patient’s body are dangerous due to possible heating and displacement under the influence of an electromagnetic field. The procedure is also not carried out in the presence of implanted electronic devices, the operation of which may be disrupted in a magnetic field. During pregnancy, MRI is prescribed with great caution and only if absolutely necessary. The doctors’ alertness is due to the unexplored influence of magnetic fields on the fetus.
MRI of the intestine is always performed with contrast, so a separate group of contraindications is associated with a contrast agent. The main conditions for the safe use of contrast are the absence of allergies and the preserved excretory function of the kidneys. During the examination, the patient should be motionless, the inability to ensure complete immobility (childhood, epilepsy, mental disorder) also becomes an obstacle to the study. Pronounced obesity is considered as a relative contraindication, the admissibility of the examination depends on the capacity and load capacity of a particular device.
Accurate visualization of the intestine during the scan may be hindered by the food there and natural peristaltic waves. Careful preparation for the procedure is required to minimize these factors. Two days before the MR enterography, black bread, legumes, cereals, fruits and other products that increase gas formation are excluded from the diet. A cleansing enema is performed the night before. If the patient suffers from constipation, it is necessary to take a laxative.
A light breakfast is allowed on the day of the procedure. A remedy for normalization of peristalsis is also prescribed. About an hour before the examination, the patient drinks 1 liter of still water and takes an antispasmodic drug. Half an hour before the start of the scan, the patient drinks 1 liter of water with a contrast agent diluted in it. During the scanning process, M-holinoblockers are often introduced to weaken peristalsis. All stages of preparation allow you to achieve maximum image clarity.
Methodology of conducting
Previously, it is necessary to leave all metal objects (watches, hairpins, etc.) in the room to get results. During MR enterography, the patient is on a couch in the center of a cylindrical tomograph. The recommended position is lying on your stomach. For convenience, you can put rollers under your head and legs. During the scanning process, the device makes loud noises, so the subject can use earplugs or headphones. Throughout the procedure, the doctor and the patient communicate through a two-way communication system.
The scan takes about an hour, taking into account the preparation, the duration of the examination is about two hours. During the operation of the tomograph, the patient may feel heat in the area under study. Some images are taken at the moment of breath retention, which the radiologist previously informs the patient about. Possible complications of MR enterography are associated with the medications taken. In particular, M-holinoblockers can cause diarrhea in the next few days after the procedure. The contrast agent injected is hypoallergenic, but can cause complications in chronic renal failure. The result of an MR enterography is prepared within a day and is given to the patient in the form of snapshots. It is also possible to write to disk or USB.