Ileal Crohn's disease: CEUS determination of activity.

Transabdominal ultrasound is currently accepted as a clinical first-line tool in the assessment of Crohn's disease activity. During recent years, great improvements have been achieved in ultrasound examination with the introduction of high-frequency transducers, ultrasonographic microbubble contrast agents, and dedicated contrast-specific ultrasound software. Therefore, contrast-enhanced ultrasonography (CEUS) is emerging as one of the most important imaging techniques in the diagnosis and follow-up of patients with ileal Crohn's disease. It is non-invasive and non-ionizing, easily repeatable, well-tolerated by patients and has significant diagnostic accuracy. Moreover, the possibility to monitor response to therapies, describing, and quantifying contrast enhancement behavior by specific software, represents an interesting aspect of its utilization, considering the still open questions about the correct use of immunosuppressive and biological agents. The aim of our review is to provide an updated overview of the role of CEUS in the patients who have an ileal localization of Crohn's disease, defining its qualitative and quantitative features.