Purpose or Case Report: Use of ultrasound for detection of midgut malrotation and volvulus has evolved and become more accepted as the first line assessment for this emergent pathology given its portability, ubiquity, and cost savings. Despite best efforts and experienced sonographers, visualization of an intraperitoneal D3 segment is both the most specific for malrotation as well as the most inconsistently seen. Contrast enhanced ultrasound (CEUS) has been used in pediatric patients for many different applications. Initially for detecting vesicoureteral reflux and subsequently expanded its utility into numerous intravascular and intracavitary applications. We aim to test the feasibility of using enteric US contrast to visualize the D3 segment.
Methods & Materials: Ultrasound contrast dilution was performed in saline to assess visualization at a diluted concentration in volumes suitable for oral intake. One standard vial of ultrasound contrast (Lumason, Bracco Diagnostics, Monroe Township, NJ), containing 25 mg lipid-type A microspheres in 5 mL sodium chloride 0.9% solution, were diluted into 50-, 100-, and 200-mL volumes of saline (1:50, 1:100, and 1:200).
In vivo animal testing: Under fluoroscopic guidance, a nasoduodenal (ND) tube was advanced into the proximal duodenum of a pig model under anesthesia. US contrast was injected through the ND tube at 1:50, 1:100, and 1:200 dilutions under direct US visualization to assess visibility of US contrast transabdominally.

Adult and pediatric volunteers were scanned while drinking 1:50, 1:100, and 1:200 dilutions of US contrast in water under direct US visualization. The probe was placed in the mid abdomen and visualization of the pylorus and SMA were confirmed prior to contrast ingestion. The probe was positioned in the trans plane just below the origin of the SMA.
Results: US contrast visualization was demonstrated at three dilutions with adequate visualization noted up to the 1:200 dilution. Direct visualization of all three dilutions of US contrast was confirmed in the pig animal model. US contrast in water was visualized at three dilutions to adequately identify bowel coursing between the SMA and aorta.
Conclusions: Ingested US contrast is visible transabdominally at dilutions up to 200mL. Enteric US contrast may be used in conjunction with current midgut volvulus protocols to enhance visualization of the retro-mesenteric course of the D3 segment. Refinement of this technique has the potential to reduce the need for follow up fluoroscopic upper GI for small bowel rotation.