Comparative Accuracy of Transperineal Ultrasound (TPUS) Versus Magnetic Resonance Imaging (MRI) for the Assessment of Perianal Fistulae in Patients With Crohn's Disease (CD): a Prospective Observational Longitudinal Cohort Study

Crohn's disease (CD) is a life-long chronic inflammatory bowel disease (IBD) that may affect any site of the gastrointestinal tract, most frequently the ileum and colon. It is characterized by transmural inflammation and it can lead to strictures, due to activation of reparation of inflamed tissues and consequent fibrosis, or penetrating lesions, such as fistulas, between two different intestinal tracts or between intestine and surrounding organs. Fistula occurrence can lead to formation of abdominal or pelvic abscesses. Such complications cause intestinal damage and usually require surgery, leading to disability, impairment of patients' quality of life, with significant impact on direct and indirect health-care costs