Reply to comment on "Ultrasonographic scores for ileal Crohn's disease assessment: better, worse or the same as contrast‑enhanced ultrasound?

We read the comments by Nylund K et al. regarding our paper "Ultrasonographic scores for ileal Crohn's disease assessment: Better, worse or the same as contrast‑enhanced ultrasound?". Intestinal ultrasound has become one of the most valuable developments in the past decade, a non-invasive, well-tolerated exam, with an easy repeatability, and absence of sedation, ionizing radiation, or preparation. Particularly for inflammatory bowel disease, where there is a lack of agreement of patient's symptoms with disease activity, in an era where the paradigm of mucosal healing is changing to transmural healing, and with the emergence of several therapies leading to repeated imaging surveillance, it is essential to highlight the role of intestinal ultrasound. Although intestinal ultrasound is an increasingly used tool to monitor inflammatory bowel disease activity, there is no widely accepted reproducible activity index, since the methodology for the development of the scores was shown to be insufficient in most studies and none have been adequately validated (Bots et al., J Crohns Colitis 12:920-9, 2018). In our study, we showed that the contrast-enhanced ultrasound (CEUS) peak enhancement derived from the time-intensity curve (TIC) is a promising non-invasive emerging method with a good accuracy to correlate clinical and endoscopic activity in the terminal ileum, superior to intestinal ultrasound scores relying on bowel wall thickness and colour Doppler.