P1.229: Quantitative Ultrasound Assessment of Intestinal Motility for Evaluating Premature Infant Health and Necrotizing Enterocolitis

Background: Necrotizing Enterocolitis (NEC) is a life-threatening gastrointestinal disease, with a 20-40% mortality rate, that predominantly affects premature infants. The gold standard diagnosis of NEC is an abdominal x-ray. These X-ray findings can confirm diagnosis but are only made in severe stages of NEC. Computational analysis of intestinal deformation observed via abdominal ultrasound (US) is an emerging novel, non-invasive methodology to assess intestinal motility in premature infants that may provide reliable and accurate quantitative measures of intestinal functional motility to allow for assessment of intestinal health and improve the diagnosis and prognosis of NEC. We hypothesize that quantitative and objective assessment of intestinal motility from abdominal US imaging can provide critical clinical imaging biomarkers to improve the diagnostic precision of US imaging for NEC.

Methods: We performed a retrospective chart review acquiring a preliminary cohort of 16 premature infants with cine abdominal US videos of intestinal peristalsis. Using a validated intestinal motility analysis methodology, we evaluated the intestinal motility index for each US video within each abdominal quadrant for each premature infant. Deformation fields are extracted and computationally processed to yield an overall measure of the degree of expansion and contraction occurring within the intestinal tissue during the US video clip. We assessed the US motility index in subjects diagnosed with NEC and compared to the US motility index in subjects that had recovered from NEC. To assess measurement variability, we calculated the coefficient of variation for the motility indexes measured across the four quadrant locations in each subject. This study was approved by the Institutional Review Board of Wake Forest University Health Sciences.

Results: A total of 9 US scans were analyzed from 9 subjects, with 20 scans from subjects diagnosed with NEC and 20 scans from subjects recovered from NEC. Post-processing of data was performed to calculate the intestinal motility index scores for comparison between the NEC positive and recovered control subjects. The mean motility index for NEC positive subjects was found to be 0.06 +/- 0.019, while the mean motility index for the control subjects was 0.10 +/- 0.015. A two-tailed unpaired t-test showed a statistically significant difference in the US motility index between NEC and control with p< 0.0001.

Conclusion: There is a significant association between motility index scores and NEC diagnosis, whereby subjects diagnosed with NEC show a lower intestinal motility index score of approximately 40% as compared to control. This study is limited by the overall number of subjects that fit our criteria with usable US imaging data. This retrospective study serves as an important proof-of-concept demonstration of the utility of quantitative assessment of intestinal motility in the diagnosis of NEC and provides significant motivation for the prospective extension of this research with more subjects in the future.