The Essential Role of High-resolution MRI Fistulogram Imaging with Ultrasound Gel Enema in Diagnosing Complex Rectovaginal Fistulas Post-Chemoradiation for Rectal Cancer: A Case Study Review

BACKGROUND: Rectovaginal fistula (RVF) is a rare and severe complication that may follow chemoradiation treatment of rectal cancer. The limitations of traditional imaging modalities are due to the diagnostic difficulty of rectovaginal fistula (RVF) caused by vague symptomatology. However, because pelvic MRI fistulogram offers better contrast in soft-tissue and multi-planar image viewing, which are very important for accurate diagnosis and efficient treatment planning, it has become the ultimate choice for the evaluation of RVF. CASE PRESENTATION: A 36-year-old female who had previously been diagnosed with rectal cancer and had undergone a chemoradiation regimen experienced a clinical response to treatment. Subsequently, she returned to our office with complaints of new-onset pelvic pain. The patient underwent a high-resolution pelvic MRI fistulogram using an ultrasound gel as an enema agent. The imaging revealed a well-defined fistulous tract between the rectum and vagina, with uncertain residual mural thickening, which significantly impacted her clinical course. CONCLUSION: This case demonstrates how to use high-resolution ultrasound gel to visualize an undetected rectovaginal fistula and reinforces the importance of this technique in understanding associated disorders and helping the interdisciplinary team make decisions regarding RVF.