Photoacoustic imaging of intestinal physiological biomarkers in infants and children

Background

A major hallmark of necrotizing enterocolitis (NEC) is intestinal hypoxia, but detection of this feature is difficult. Photoacoustic imaging (PAI) is an emerging imaging method to noninvasively visualize intestinal oxygenation and microvasculature and is promising for improved NEC detection. Prior to clinical translation of PAI for NEC detection, initial studies must be performed in a pediatric population to assess safety and feasibility.

Methods

Under IRB approval, eighteen healthy pediatric participants underwent PAI scans before and after eating a lipid-rich snack. PAI was acquired in each abdominal quadrant with intestinal regions-of-interest (ROI) manually drawn on each image series to measure averaged values of deoxygenated hemoglobin (Hb), oxygenated hemoglobin (HbO ₂ ), total hemoglobin (HbT), and oxygen saturation (sO ₂ ).

Results

Minor temporary erythema and pressure from safety goggles in some participants were the only adverse events reported. Pre-/post-prandial changes for HbT, HbO2, Hb, and sO2 were assessed for each abdominal region and age cohort. Results showed significant post-prandial hyperemia in the intestines with no changes in bowel oxygenation.

Conclusions

PAI is a safe and feasible imaging modality for evaluating intestinal blood flow in pediatric patients that detects physiological changes in bowel microvasculature and shows strong potential as a quantitative biomarker for assessment and monitoring of intestinal vascular health.

Highlights

• Pediatric abdominal PAI is safe: Only minor, temporary, and immediately reversible adverse events were reported due to goggles

• Pediatric abdominal PAI is feasible: Excellent sensitivity for detecting changes in intestinal microvascular biomarkers

• First-in-early-pediatric study: Our findings support the translational use of PAI for assessing intestinal vascular health