Learn techniques of pelvic floor dynamic magnetic resonance imaging, defecography (MRI)

The article was written by Dr. Dang Manh Cuong - Department of Diagnostic Imaging - Vinmec Central Park International General Hospital.

Magnetic resonance imaging (MRI) is a non-invasive imaging technique used to diagnose many different diseases. An MRI uses a strong magnetic field, radio waves, and a computer to create detailed images of structures inside the body.

Pelvic floor dynamic magnetic resonance imaging, defecography (MRI) is a special imaging technique, it records images at different stages of defecation. It captures a sequence of images such as video during defecation and provides information about the anatomical structure and function of the rectum and pelvic floor, the tense muscles between the pubic bone and the spine, and the support of the organs. abdomen in the pelvis.

The doctor will order pelvic floor dynamic magnetic resonance imaging, defecography (MRI) in the following cases:
Get information about how the pelvic floor muscles work during bowel movements convenient; Evaluation of rectal function; Determine the cause of bowel incontinence (faecal incontinence); Identify the cause of constipation; Diagnose and evaluate diseases that affect rectal function and pelvic floor disorders (also called pelvic floor dysfunction), such as hernias, pelvic organ prolapse (eg. bladder, urethra, uterus, and vagina) or rectal prolapse (a condition in which part or all of the wall of the rectum recedes from its normal position); Provides information for surgical and treatment planning.

In order to conduct a pelvic floor MRI session to be effective, the patient needs to prepare a few things as follows:
The patient may need to wear a hospital gown or the patient may need to wear a hospital gown. to wear one's own clothing if it is loose and does not contain any metallic materials; Get specific instructions about eating and drinking from your doctor before having a pelvic floor MRI; When a contrast agent injection is indicated, the patient may be asked about his or her medical condition, whether the patient has asthma or is allergic to iodinated contrast agents, drugs, foods, or the environment; Tell the technician or radiologist if the patient has any serious health problems or has had recent surgery. Certain conditions, such as severe kidney disease, may require the use of special gadolinium contrast agents that are considered safe for patients with kidney disease. The patient may need kidney function tests to determine if the patient's kidneys are working properly; Tell the doctor and technician if the patient is pregnant. MRI has been used since the 1980s with no reports of any adverse effects on pregnant women or their unborn babies. However, the baby will be in a strong magnetic field, so pregnant women should not have an MRI during the first trimester unless the benefits of the scan outweigh the potential risks. Pregnant women should not receive gadolinium contrast injection unless absolutely necessary; If the patient has claustrophobia (fear of confined spaces) or anxiety, the patient may ask the doctor to prescribe a mild sedative prior to the examination; Leave all jewelry and other accessories at home or remove them before the MRI scan. Metal and electronic items can interfere with the magnetic field of the MRI machine and they are not allowed in the imaging room. They can cause burns or become harmful in the MRI machine room. These include: Jewelry, watches, credit cards, and hearing aids. Because all can be broken; Pins, hairpins, metal zippers and similar metal objects. These objects can distort the MRI image; Removable dentures; Pens, pocket knives and eyeglasses; Recommended to wear on the body; Cell phones, electronic watches and tracking devices. In most cases, an MRI is safe for patients with metal implants, with some exceptions. People with the following implants may not be screened and should not enter the MRI area without first being evaluated for safety:
Certain cochlear implants; Several types of clips are used for brain aneurysms; Some types of metal coils are placed in the blood vessels; Some older defibrillators and pacemakers. Immediately notify the technician if the patient has medical devices or electronic devices in the body. These devices may interfere with the shooting process or pose a risk. Many implantable devices will have an instruction manual for the device that explains the MRI risks for that particular device. The patient needs to bring it to the doctor to see when the scan is done. MRI cannot be performed without confirmation and documentation of implant type and compatibility with MRI.
Metal objects used in orthopedic surgery generally pose no risk in MRI. However, some metallic materials may not be compatible with MRI and need to be indicated using a different imaging technique.
The patient should tell the technician or doctor about any shrapnel, bullets or other metal present in the body. Foreign objects near and especially in the eye are important because they can move or heat up during the scan and cause blindness. The dye (tattoo ink) used in tattoos may contain iron and can heat up during the MRI scan and cause burns, which are rare.
Dental fillings, braces, eyeshadows and other cosmetics are generally unaffected by magnetic fields. However, they can distort images of the face or brain area.

This technique can be performed on outpatients as well. Patients will be asked to drink fluids 30 minutes before the scan. Your rectum will be filled with a gel that looks like an ultrasound gel. A pad will be placed under the buttocks to absorb the urine or gel expelled during the procedure The patient will be placed on a movable table, lying on his back A device with coils capable of sending and receive radio waves (radio waves) that will be placed over the patient's pelvis Examination will be performed by a technician at a computer outside the room Image will be obtained during bowel movements including contractions, straining, and defecation Images will also be taken while the patient's muscles are at rest The technician will guide the patient during the scan. This technique is usually done in about 30 - 45 minutes

Most MRI exams are painless. However, there are some patients who are uncomfortable for the following reasons:
Feeling claustrophobic in the MRI scanner (clautrophobic syndrome). So some patients who feel anxious may need to be sedated Feeling noisy when the MRI machine pulses The patient's lying area may feel a bit hot, but that's normal. However, if you feel any discomfort, it is important to inform the technician or doctor, because it is important that the patient remain completely still during the scan. Feel the loud knocking sound when the coils that generate the radio frequency pulses are activated. Some centers provide earplugs, while others use headphones to reduce the intensity of the sound produced by the MRI machine. This will allow the patient to relax between pulses, but remain in the same position without moving as much as possible. The patient will usually be alone in the MRI room. However, the technician can still see, hear and talk to the patient at all times using the two-way intercom. If you are concerned about the need for a loved one to be with you, a request can be made as long as the loved one is also screened for safety before entering the MRI room. Children will be fitted with properly sized earplugs or headphones during the search. Music can be played through headphones to help a child get through long periods of lying down Some patients experience mild bloating or cramping when the contrast material is inserted into the rectum Patients can resume normal activities normal and normal diet immediately after examination.

Benefits:
Pelvic floor dynamic MRI helps to evaluate pelvic floor abnormalities that are difficult to diagnose clinically and other imaging techniques such as computed tomography, rectal endoscopy and colonoscopy MRI is a technique non-invasive imaging, no radiation exposure MRI images of the body's soft tissue structures (such as the heart, liver, and many others) are clearer and more detailed than conventional imaging methods other photo. This makes MRI a valuable tool in the early diagnosis and evaluation of cancer. musculoskeletal MRI can help doctors evaluate both the structure of an organ and how it functions. Risks:
An MRI scan poses almost no risk to the patient if proper safety instructions are followed Although strong magnetic fields are not harmful by themselves, implanted medical devices that contain metal can may be damaged or cause problems during the MRI scan.

For high quality, shake-free images, the patient must lie still during the scan and follow instructions to hold their breath while the image is being recorded. If the patient is in pain or anxious, it is difficult to lie still and the image will be blurred
People who are too heavy may not be suitable for certain types of MRI machines. Because there is a weight limit on the camera.
Implants and other metal objects can make the image not clear. Patient movements can be of a similar nature.
Very irregular heartbeat may affect image quality. This is because some techniques are based on the electrical activity of the heart.
Although there is no evidence that MRI harms an unborn baby, pregnant women should not have an MRI during the first trimester, unless it is absolutely medically necessary.
Vinmec International General Hospital put into use the magnetic resonance imaging machine 3.0 Tesla Silent technology. Magnetic resonance imaging machine 3.0 Tesla with Silent technology of GE Healthcare (USA).
Silent technology is especially beneficial for patients who are children, the elderly, weak health patients and patients undergoing surgery. Limiting noise, creating comfort and reducing stress for customers during the shooting process, helping to capture better quality images and shorten the shooting time. Magnetic resonance imaging technology is the technology applied in the most popular and safest imaging method today because of its accuracy, non-invasiveness and no use of X-rays. Customers can go directly to the system. Vinmec Health System nationwide to visit or contact the hotline HERE for support.
References: https://www.radiologyinfo.org/en/info.cfm?pg=defecography-mri

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