Fistula MRI Scan: Cost, Report Analysis, Preparation, Result

Fistula magnetic resonance imaging (MRI) is a technique that creates a clear image of the anal canal, sphincter muscles and soft tissues surrounding the anus.

In a fistula MRI scan, strong electronic and magnetic waves are used to create multiple 3D images. These images are stored on electronic devices and studied by a doctor to determine a suitable treatment plan or surgical procedure. 

A fistula MRI exam helps in determining the exact location of fistula tracts. It also helps in checking if any abscess has formed. Moreover, these scans assist in assessing the site of a fistula's external and internal openings before surgery. 

Types of Fistulas

A fistula is an abnormal structure connecting two hollow spaces like intestines, blood vessels or other hollow organs. Depending on their location and course, fistulas can be categorised into different types. These include:

1. Entero-enteral fistula: It occurs between two different parts of the intestine.
2. Enterocutaneous fistula: It occurs between the skin and the small intestine.
3. Perianal fistula: A tunnel-like structure in the tissue around the anus. 
4. Rectovaginal fistula: It occurs in females between the rectum and the vagina.
5. Anovaginal fistula: It occurs in females between the anus and the vagina.
6. Anal fistula: A tunnel-like structure between the skin around the anus and the end of the bowel. Anal fistulas can be further classified into the following types:
   1. Intersphincteric fistula: It originates from the anus and runs between its outer and inner sphincter muscles.
   2. Trans-sphincteric fistula: It originates from the anus and runs through its outer sphincter muscle into the surrounding tissue.
   3. Suprasphincteric fistula: It originates from the anus and runs above its sphincter muscles and into the surrounding tissue.
   4. Extrasphincteric fistula: It originates from the anus and runs outside its sphincter muscles and into the surrounding tissue.

A fistula MRI is a sensitive and particular diagnostic test for detecting fistulas. It helps in determining how many tracts there are as well as their location. A fistula MRI scan can serve a variety of purposes. These include:

1. Diagnosis of various fistulas: A fistula MRI exam helps diagnose anal fistulas, perianal fistulas, and other fistulas, including those in urinary and gastrointestinal tracts.
2. Check for obstetric fistula: An MRI fistulogram can help detect an obstetric fistula, which is a major complication of childbirth.
   It occurs when the head of the baby puts pressure on the mother's pelvis for a prolonged period, resulting in a hole in the wall of the rectum or bladder. 
3. Rule out inflammatory bowel disease (IBD): A contrast-enhanced fistula MRI exam can help doctors check large and small intestines and associated fistulas for IBD, which causes ulceration, inflammation and scarring in the digestive tract. 
4. Measure the success of fistula surgery: An MRI fistulogram is also ordered immediately after surgery to assess the procedure's success. The MRI conducted for this purpose is usually done without contrast.

Doctors order an MRI fistulogram to scan and detect the current condition of fistulas in the body. A doctor may ask a patient to get a fistula MRI scan in case the following symptoms of anal fistulas are present:

1. Swelling or redness around the anus
2. Skin irritation around the anus
3. Fever
4. Blood or pus in stools
5. Foul-smelling discharge near the anus
6. Difficulty controlling bowel movement
7. Consistent, throbbing pain around the anus, which increases on moving around, sitting, passing stools, or coughing

A doctor may also order a fistula MRI exam in case of the presence of the following symptoms of rectovaginal and anovaginal fistulas:

1. Passage of gas and faeces through the vagina
2. Vaginal discharge
3. Inflammation of the vagina (vaginitis)

Who cannot get a fistula MRI scan done?

People with one or more of the following medical implants cannot get a fistula MRI scan done without being assessed for MRI compatibility. This is because these implants can interfere with the MRI machine and damage the machine or the patient.

1. Ear implants
2. Artificial joints
3. Metal coils placed inside blood vessels
4. Cardiac defibrillators and pacemakers
5. Clips used for brain aneurysms

How is fistula MRI performed?

A fistula MRI scan can take anywhere between 30 minutes and 60 minutes. The procedure for a fistula MRI includes the following steps:

1. The patient is positioned on a movable examination table. In some cases, straps may be used to keep the patient still during the procedure.
2. An intravenous (IV) line is inserted into a vein in the patient's hand or arm to inject the contrast material that helps in improving the visibility of fistulas in images.
3. A device equipped with coils that receive and send radio waves is placed around the part of the body to be scanned.
4. Then, the patient is moved to the scanner’s centre while the MRI operator works on a connected computer in the adjoining room. 
5. Sometimes, a rectal enema is given to the patient using a catheter, particularly when the doctor suspects that all present fistulas will not be visible on the MRI scan. 
6. When the catheter is removed, the patient will be asked to pass stool as the increased rectal pressure forces the contrast through fistulas. 
7. Then, the scan is repeated and the images are saved in the computer. 

How to prepare for a fistula MRI exam?

MRI for detecting fistulas is a very simple test and doesn't require much preparation. There are just a few things that patients should remember before going in for the test. Here is a list of a few things a patient will have to do before getting a fistula MRI scan done:

1. Give detailed history: A patient must inform the doctor of any allergies, ongoing medications and previous reactions to contrast materials. 
2. Get the blood test done: A doctor will ask the patient to get a blood test done beforehand. This test is vital before an MRI fistulogram.
3. Remove all metal objects: The patient must remove all metal objects before the test. These include jewellery, hair clips and watches as these objects can interfere with the MRI machine.
4. Keep the doctor informed: It is essential to inform the doctor of any implanted medical devices or metallic implants that need to be checked for MRI compatibility. 
5. Loose, comfortable clothes: The patient should wear comfortable and loose clothes to the procedure, where they may or may not be asked to wear a hospital gown.
6. Avoid drinking or eating: The patient should not eat or drink anything before the procedure as the contrast material may cause vomiting or nausea if the patient’s stomach is full.

What happens after a fistula MRI exam?

After a fistula MRI exam, the patient will be monitored to check for any reaction to the contrast material.

The IV line will be removed, and the patient may or may not experience mild side effects like warm sensation or dizziness due to contrast materials. These side effects usually resolve quickly on their own. 

If a patient is not sedated during the fistula MRI exam, then no recovery period is necessary, and he/she can carry on with routine activities like usual.

The doctor will then discuss the results of fistula MRI with the patient and offer all the necessary information related to follow-up care. In some cases, the doctor may advise the patient to:

1. Not to lift heavy weights
2. Avoid running or driving
3. Avoid smoking or drinking alcohol
4. Wear tight clothes to keep the skin away from getting air

Fistula MRI is a clean, quick and simple procedure to obtain necessary information about fistulas within the body. It helps patients as well as doctors in a plethora of ways. Following are some of the significant benefits of a fistula MRI scan:

1. It is entirely non-invasive.
2. A fistula MRI exam is highly accurate in the assessment of fistulas.
3. These scans are quite helpful in planning the surgery for fistulas.
4. A fistula MRI exam does not cause any radiation exposure.
5. It provides sufficient information that helps avoid invasive procedures.

An MRI fistulogram is typically a safe and painless procedure. However, like with most procedures, it comes with its own set of risks. The following are some risks associated with a fistula MRI scan:

1. Exposing a pregnant woman to strong magnetic fields during the first trimester can be dangerous to the foetus.
2. The strong magnetic field of the MRI machine can distort the images or adversely affect the functioning of any implanted medical devices. 
3. The procedure can cause discomfort to the patient due to its loud noise, confined space, and need for lying still for a prolonged period.
4. The contrast material used during the procedure may cause allergic reactions, leading to hives, itching, rash, chest pain, trouble breathing and swelling.
5. In rare cases, this contrast material can also cause kidney damage, especially in those suffering from pre-existing kidney disease.

There is no fixed price of an MRI fistulogram. The cost of a fistula MRI scan can vary depending on:

1. Location of fistula: The cost of the procedure can vary as per the location of fistula, which means it can be different for anal fistulas, rectovaginal fistulas and anovaginal fistulas.
2. City in which a diagnostic lab is located: Diagnostic labs in tier 1 cities like Hyderabad, Bengaluru and Delhi NCR charge more than those in tier 2  and tier 3 cities.