The disease activity index under intestinal color ultrasound was evaluated by SUS-CD, and the disease activity index under capsule endoscopy was evaluated by CECDAI. All subjects underwent intestinal color ultrasound and capsule endoscopy at baseline and at the third month of treatment. To compare the correlation between SUS-CD and CECDAI before and after treatment, and to compare the role of intestinal color ultrasound and capsule endoscopy in monitoring Crohn's disease in small intestine.

The disease activity index under intestinal color ultrasound was evaluated by SUS-CD, and the disease activity index under capsule endoscopy was evaluated by CECDAI. Active lesions under intestinal color ultrasound were defined as SUS-CD ≥ 1, and active lesions under capsule endoscopy were defined as CECDAI ≥ 3.9. All subjects underwent intestinal color ultrasound and capsule endoscopy at baseline and 3 months after treatment. To compare the correlation between SUS-CD and CECDAI before and after treatment, and to compare the role of intestinal color ultrasound and capsule endoscopy in monitoring Crohn's disease in small intestine.

Inclusion Criteria:

• 1.Patients diagnosed with Crohn's disease according to the 2019 European Guidelines for Crohn's disease;
• 2.At the time of inclusion, there were active lesions under color ultrasound or capsule endoscopy;
• 3.Voluntarily sign an informed consent form.

Exclusion Criteria:

• 1.Patients with contraindications for capsule endoscopy;
• 2.In the judgment of the investigator, it is not suitable to participate in this study.

Patients diagnosed with Crohn's disease according to the 2019 European Guidelines for Crohn's disease.