A Study Comparing Transperineal Ultrasound, Magnetic Resonance Imaging, Endoscopic Ultrasound, and Examination Under Anesthesia to Detect and Classify Perianal Fistulas in Patients With Crohn's Disease or Fistulas of Unknown Cause

Condition(s) studied

Investigational drug(s) / intervention(s)

Transperineal Ultrasound (TPUS): Participants will undergo TPUS using a high-frequency linear and microconvex probe to evaluate fistula tracts, internal openings, and abscesses.

Magnetic Resonance Imaging (MRI): MRI of the pelvis will be performed using standardized T2-weighted, STIR, and post-contrast sequences for anatomical characterization of fistulas.

Endoscopic Ultrasound (EUS): EUS of the anorectal canal will be performed using a linear echoendoscope to visualize internal openings, fistula tracts, and perirectal collections. EUS serves as the reference standard.

Examination Under Anesthesia (EUA): Participants will undergo EUA by a colorectal surgeon to probe fistula tracts and identify internal openings. EUA serves as the gold standard comparator.

Study summary

The goal of this study is to learn how well different imaging tests detect and describe perianal fistulas in adults with Crohn's disease or fistulas with no known cause (cryptogenic). Perianal fistulas are painful tunnels that form near the anus and can lead to discharge, swelling, or infection. The main questions this study aims to answer are:

How accurate is transperineal ultrasound (TPUS) compared to magnetic resonance imaging (MRI) in finding fistulas? How well do these tests identify key features like internal openings and abscesses? Do the test results help doctors make better treatment decisions?

Researchers will compare TPUS and MRI to two other imaging methods:

Endoscopic ultrasound (EUS), which uses a small camera and ultrasound inside the rectum Examination under anesthesia (EUA), in which a surgeon checks the area while the participant is asleep

All participants will:

Be adults between the ages of 18 and 75 Have a suspected or confirmed perianal fistula Be able to complete all four tests-TPUS, MRI, EUS, and EUA-within 10 days Participants will not receive any experimental treatments. The tests are part of routine care and will be done using advanced equipment by expert doctors. Each test result will be used to compare how accurate and useful the test is in real-life diagnosis and treatment planning.

This study may help make fistula diagnosis faster, safer, and more affordable-especially in settings where access to MRI or surgery is limited. It may also support the use of TPUS as a first step in evaluating perianal fistulas in people with Crohn's disease.

Eligibility

Primary outcome measure(s)

• Per-lesion sensitivity of transperineal ultrasound (TPUS) and magnetic resonance imaging (MRI) for detecting perianal fistulas — Within 10 days of enrollment (all four imaging modalities completed within this window)
  To determine and compare the diagnostic sensitivity of TPUS and MRI for identifying individual fistulous tracts, using endoscopic ultrasound (EUS) as the reference standard and examination under anesthesia (EUA) as the gold standard.

Trial sites (1)

More Asian Institute of Gastroenterology, India trials in India

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