Intestinal Ultrasonography as an Alternative to Fecal Calprotectin to Monitor Patients with Crohn’s Disease: Experience from a Novice Sonographer

Background

While fecal calprotectin (Fcal) is now recommended, the positioning of intestinal ultrasonography (IUS) is still unknown to monitor patients with CD.

Aims

To assess the agreement between IUS performed by a novice sonographer and Fcal to detect active CD and to compare these two monitoring tools to determine the need for therapeutic escalation.

Methods

In this cross-sectional prospective study, we consecutively included CD patients ≥ 18 years-old with concomitant IUS and Fcal testing within 7 days. IUS was performed by a novice sonographer. The endpoints were the agreement between IUS and Fcal (> 150 µg/g) to detect active CD and the need for therapeutic escalation.

Results

Among 66 patients undergoing IUS, 56 patients had also Fcal testing. The agreement between IUS and Fcal to detect an active CD was 80.4% (κ-coefficient = 0.536 ± 0.127). Fcal, IUS or both had respectively the following positive (76.9%[54.0–99.8], 70.0%[49.9–90.1], and 81.8%[59.0–100.0]) and negative (81.4%[69.8–93.0], 88.9%[78.6–99.2], and 80.0%[68.3–91.7]) predictive values to detect active CD requiring therapeutic escalation. Using a 10 points-acceptability numerical scale, IUS presented with a better acceptability than Fcal (9.5 ± 1.2 vs 8.0 ± 2.3, p < 0.0001). Contrary to the agreement with Fcal and the performances of IUS to identify the need for therapeutic escalation, the duration of IUS procedure decreased over time (correlation coefficient = − 0.54, p = 0.001) and plateaued between 15 and 20 min-long from the 24th procedure.

Conclusion

IUS and fecal calprotectin do not give the same information and could be complementary to monitor patients with CD.

Graphical Abstract