Sonofistulogram Ultrasound Scan

A Sonofistulogram, often referred to as a fistula ultrasound, is a safe, non-invasive, and highly detailed diagnostic imaging test. Its primary purpose is to accurately map the complex paths of fistula tracts, which are abnormal tunnels connecting different parts of the body. This test is particularly effective for evaluating perianal fistulas—those occurring near the anus.

At Cadabams Diagnostics, our experienced radiologists use state-of-the-art ultrasound technology combined with a safe contrast agent, such as agitated saline or hydrogen peroxide. This technique allows us to visualize the entire fistula tract in real-time, providing clear and precise images that are crucial for your doctor to plan the most effective treatment.

What is a Sonofistulogram?

In simple terms, a Sonofistulogram is a specialized ultrasound designed to evaluate abnormal connections or tunnels, known as fistulas. Unlike a standard ultrasound, this procedure involves enhancing the images with a contrast agent.

During the test, a small, specialized ultrasound probe is gently inserted (most commonly endoanally for perianal fistulas). The contrast solution is then slowly injected into the external opening of the fistula. As the solution travels through the tract, the ultrasound machine captures dynamic images, highlighting its exact path, size, and any associated complications like abscesses.

This detailed visualization provides your surgeon with an essential "roadmap" of the fistula. Understanding this anatomy is critical for planning a successful surgery that aims to cure the fistula while preserving important surrounding structures, like the anal sphincter muscles.

Types of Sonofistulogram

The overwhelming majority of Sonofistulogram procedures performed are endoanal or transperineal ultrasounds, specifically for diagnosing and mapping perianal fistulas. This is the primary and most established application of the technique.

While the same principle can theoretically be adapted to evaluate fistulas in other accessible parts of the body (e.g., enterocutaneous fistulas on the abdominal wall), its use is less common for these areas. For most patients, when a doctor orders a Sonofistulogram, they are referring to the specialized ultrasound for anal fistula evaluation.

During the procedure, our radiologist meticulously evaluates several key parameters to create a comprehensive report. These details are vital for your surgeon.

• Primary Fistula Tract: The main path of the fistula is identified and classified based on its route (e.g., intersphincteric, transsphincteric, suprasphincteric).
• Internal and External Openings: The exact locations where the fistula begins (internal opening, usually inside the anal canal) and ends (external opening, on the skin) are precisely located.
• Relationship to Anal Sphincter Muscles: The report details how the tract passes through or around the internal and external anal sphincter muscles, which are crucial for bowel control.
• Associated Abscesses: The presence, size, and location of any connected pockets of infection (abscesses) are noted.
• Secondary Tracts or Ramifications: The exam identifies any additional branches or complex pathways extending from the primary tract.

A Sonofistulogram is a powerful diagnostic tool ordered for several important reasons:

• To Investigate Symptoms: It provides a definitive diagnosis when a patient has symptoms of an anal fistula, such as persistent pain, discharge, or skin irritation.
• To Plan for Surgery: This is a critical role. By providing a detailed map, the ultrasound for anal fistula allows the surgeon to plan the most effective and safest surgical approach, aiming to minimize recurrence rates and preserve sphincter function.
• To Evaluate Healing: In some cases, it can be used after surgery to confirm that the fistula has healed completely.
• To Clarify an Unclear Diagnosis: When a physical examination is inconclusive, the Sonofistulogram can accurately confirm or rule out the presence of a fistula.

When and Who Needs to Take a Sonofistulogram?

Your doctor may recommend a Sonofistulogram if you are experiencing symptoms suggestive of a fistula, or if you have a condition known to be associated with fistula formation.

Common indications for the test include:

• Persistent pain, swelling, or tenderness around the anus.
• Chronic discharge of pus or blood from an opening near the anus.
• Skin irritation or a visible hole in the skin around the perianal area.
• Recurrent perianal abscesses that don't heal properly.

Patient groups who frequently require this test are:

• Individuals with a suspected or diagnosed anal fistula: This is the most common reason for the test.
• Patients with Crohn's Disease: This inflammatory bowel disease is a major cause of complex perianal fistulas.
• Patients with a history of recurrent anal abscesses: An abscess can be the starting point for a fistula tract.
• Patients requiring pre-operative planning: Surgeons need to know the fistula's exact anatomy before performing surgery to reduce the risk of recurrence.

Benefits of Taking the Test

Choosing a Sonofistulogram offers numerous benefits for both the patient and the treating physician.

• High Accuracy: It is a highly accurate method for diagnosing and classifying perianal fistulas, rivaling the accuracy of MRI in many cases.
• Radiation-Free: The test uses sound waves, not ionizing radiation, eliminating any risks associated with radiation exposure.
• Real-Time Imaging: It provides dynamic, real-time images, allowing the radiologist to see how the contrast fills the tract as it is injected.
• Improved Surgical Outcomes: By providing a precise preoperative roadmap, it helps surgeons select the best procedure, leading to higher success rates and a lower risk of incontinence.
• Cost-Effective: It is generally more accessible and less expensive than an MRI.

Illnesses Diagnosed with US Sonofistulogram

The primary condition diagnosed and evaluated with this test is:

• Perianal Fistula (Anal Fistula): This is the classic indication for a Sonofistulogram.

The test is also essential in assessing the complications and extent of disease in patients with other underlying conditions, such as:

• Crohn's Disease
• Diverticulitis
• Hidradenitis Suppurativa
• Post-surgical or post-trauma complications

For more information on the primary condition, please read our guide.

Proper sonofistulogram preparation is simple but important for ensuring the clearest possible images. Your comfort and the quality of the test are our top priorities at Cadabams Diagnostics.

• Bowel Preparation: You will most likely be asked to administer a simple enema (such as a sodium phosphate preparation) approximately 1-2 hours before your scheduled appointment. This helps clear the rectum of any stool, which can interfere with the ultrasound images.
• Clothing: Wear loose, comfortable clothing to your appointment. You will be asked to change into a hospital gown for the procedure.
• Diet: In most cases, you can eat and drink normally on the day of the test. Our staff will confirm if any specific dietary restrictions apply to you when you schedule your appointment.

Pre-requisites

• Doctor's Referral: A referral from your doctor or specialist is required to undergo a Sonofistulogram.
• Previous Imaging: If you have had any previous imaging tests of the area (like an MRI, CT scan, or a prior ultrasound), please bring the reports and images with you. This allows our radiologist to compare findings and track any changes.

Best Time to Take the Sonofistulogram

Unlike some tests that need to be timed with hormonal cycles, there is no specific "best time" to have a Sonofistulogram. The procedure can be scheduled at your convenience based on the availability at our Cadabams Diagnostics centres.

Eligibility

Most patients with symptoms of a perianal fistula are eligible for a Sonofistulogram. However, there are a few relative contraindications:

• Severe Pain or Inflammation (Stenosis): If the area is extremely painful or swollen, it might be difficult to insert the probe. The test may be postponed until the acute inflammation subsides.
• Known Allergies: While very rare, if you have a known allergy to hydrogen peroxide or other potential contrast agents, please inform our staff beforehand.

Procedure for Taking a Sonofistulogram

The fistula ultrasound procedure is performed by a specialized radiologist in a private and comfortable setting. Our team will explain every step to you. The entire process typically takes about 20-30 minutes.

• Step 1: Positioning: You will be asked to lie on your side on the examination table, with your knees drawn up slightly towards your chest. This position provides the best access for the radiologist.
• Step 2: Probe Insertion: The radiologist will apply a lubricating gel to a small, thin ultrasound probe (about the width of a finger) and gently insert it into the anus. This may cause a feeling of pressure, but it is not typically painful.
• Step 3: Contrast Injection: The radiologist will identify the external opening of the fistula on your skin. A very fine, flexible catheter will be placed just inside the opening, and the sterile contrast solution (saline or hydrogen peroxide) will be injected slowly and gently.
• Step 4: Imaging: As the contrast fills the fistula, the radiologist will carefully move and angle the ultrasound probe to capture detailed, real-time images of the entire tract, its branches, and its relationship to the sphincter muscles.

Caution Before Taking the Test

For your safety and to ensure the most accurate results, please inform the radiologist or technologist before the procedure if you:

• Are pregnant or think you might be pregnant.
• Have any known allergies, particularly to medical solutions.
• Are experiencing severe pain or tenderness in the perianal area.
• Have had recent surgery in the perianal region.