The last decade brought a shift in therapeutic goals in pediatric Crohn's Disease (CD), from symptom control to mucosal (MH) and transmural healing. Ileocolonoscopy remains the gold standard in assessing MH, however, the use of ileocolonoscopy in pediatric patients is fraught with limitations. Surrogate markers of MH are investigated. Our study aimed to assess the utility of magnetic resonance enterography (MRE) and clinimetric methods in monitoring Leśniowski - Crohn disease treatment in pediatric patients. This preliminary, observational, single-centre research involved 60 consecutive newly diagnosed CD pediatric patients (diagnosed between 2015 and 2017 at the Department of Pediatric Gastroenterology and Nutrition, University Children’s Hospital of Cracow, Poland). The study was approved by the Bioethics Committee of the Jagiellonian University, Krakow (No: 122.6120.52.2015). The obtained results were published in a series of articles in 2021-2022. The results from a series of articles show that both MRE- based CD activity indices as well as newly developed noninvasive activity scores are helpful during the clinical decision-making process and may contribute to effective and tight monitoring of pediatric patients with Crohn’s disease.