Anal Fistula is an infected tunnel which is formed between the skin and the anus. Anal fistulas are mostly formed due to an infection in the anal gland. The infected gland keeps producing abscess or pus which creates a path to drain out of the body. This path or tunnel from the infected gland to the opening near the anus is called Anal Fistula. Knowing the complete path of an anal fistula is important for effective treatment. The opening of the tunnel at the skin (external) generally appears as a red, inflamed area that may ooze pus and blood. This external opening is usually easily detected. Finding the fistula opening in the anus (internal opening) is more complicated.
MRI Fistulogram is used for mapping the fistula tract and providing detailed images of the sphincter muscle and other structures of the pelvic floor. This helps the surgeon in planning the surgery. In Fistula surgery the surgeon has to remove the infected tissue and then flatten the tunnel either by scraping the surface of the tunnel and then stitching or using Laser Technology to burn the internal walls of the tunnel which will result in scarring and healing.
You would be required to come in fasting as MR Fistulogram might require contrast injection. In MRI we can use Gadonlinium contrast as compared to the Iodized Contrast in CT Scan which is less harmful for patients having poor kidney function. During the MRI exam, you would be in a room which has strong magnetic field. You should not be wearing any jewellery and should inform the technician if you have any kind of implant inside your body. In any case our technician would be checking you with a metal detector before taking you inside the magnet room. Before the MRI examination you are required to clear your bowels. Gadolinium or Non-ionic contrast might be used after cleaning the fistula opening with alcolhol swab. The study would take around 30-45 minutes to complete.
You are advised to leave your mobile phone, wallet and all clothes inside a locker which is provided to you. You would be given a hospital gown to wear for the test. There is a humming sound which resembles the sound of a running train while the exam is going on. You would be given ear plugs to minimize this sound. You would be required to go inside a cylinderical tunnel and lie still while the exam is going on. On completion of the test, you can change into your own clothes and leave for your home. The MRI Fistulogram exam will produce several hundred images which will be reviewed by the radiologist and the report would be made available within 24 hours of the scanning.
MRI Machines are of two types - Permanent Magnet and Superconducting Magnet. The Permanent Magnet MRI or Open MRI as it is called comes in two strengths - 0.2 Tesla and 0.3 Tesla. The Superconducting Magnet comes in strengths of 1.5 Tesla and 3.0 Tesla. Tesla is the unit for magnetic strength. The common belief is that higher the Tesla, better is the imaging quality but this is not the case. Higher magnetic strength can produce greater noise and result in lower signal to noise ratio. MRI of the Brain, Joints and Spine can be done equally well on a 0.3 Tesla Permanent Magnet as it is done on a 1.5 Tesla Magnet. However inner ear imaging is best done on a 3 Tesla MRI. Many doctors would prescribe MRI scan on a 3 Tesla Machine without knowing the difference in imaging quality. The quality of imaging also depends on the quality of coils, channels in the machine and specialized applications for doing the scanning. Finally the quality of reporting is of paramount importance in any MRI Imaging. At EHL Diagnostics we have the optimum combination of all these factors. We have all types of machines at different centres. So patients who are claustrophobic, are advised to get their MRI on open magnet of 0.3 Tesla. Patients who require extensive testing like MRI brain and whole spine would do better to go for 3 Tesla as the imaging time is lesser.
The cost of MRI Fistulogram at our centres is in the range of Rs. 8000 - 10000. If Gadolinium contrast is needed then additional amount of Rs. 3500 - 4000 is charged for the test.