Intestinal ultrasound may be a useful tool in monitoring acute rejection following intestinal transplantation

Acute rejection is the leading cause of mortality and morbidity for children following intestinal transplantation. Rapid detection and prompt treatment are critical; however, the only reliable method of diagnosis and monitoring is endoscopic graft biopsies. The required regular anesthetics are particularly problematic in children, and non-invasive strategies are needed.

We describe the intestinal ultrasound findings of three children before and after treatment for rejection. Ultrasounds were performed within 24 h of endoscopically obtained biopsies which were used to establish a diagnosis of rejection and to define severity. A single sonographer performed the ultrasounds and was blinded to biopsy results at the time of the scanning. These findings are provided in the context of the ultrasound appearance of seven children who had no features of rejection on surveillance biopsies.

Intestinal ultrasound demonstrated increased bowel wall thickness, vascularity, and mesenteric inflammation during moderate to severe rejection episodes. The submucosal layer was particularly thickened, which may represent a finding more specific for rejection. All patients demonstrated improvement in all quantitative ultrasound features correlating with the resolution of acute cellular rejection on histology. Patients with no evidence of rejection on biopsy had a bowel wall thickness range of 0.9-2.8 mm, suggesting a normal upper limit of 3 mm.

Moderate and severe acute rejection may be detected and response to treatment can be monitored by intestinal ultrasound and, correlating with clinical improvement, can aid in follow-up.