Ultrasound microvascular flow imaging: evaluating fetal mesenteric blood flow and predicting postnatal surgery in meconium peritonitis.

Objective: This study explored the characteristics of fetal mesenteric blood flow perfusion across various gestational weeks and evaluated the efficacy of Microvascular Flow (MV-Flow) imaging technology in assessing intestinal wall blood flow in fetuses with meconium peritonitis (MP).

Method: In this retrospective study, we analyzed 35 fetuses with MP and 160 healthy fetuses. We examined the correlation between the Vascular Index (VI) of mesenteric perfusion and gestational age, conducted an analysis comparing MP operative and non-operative groups, and developed a predictive model for surgical intervention.

Results: The VI value demonstrated no significant change with increasing gestational age (correlation coefficient = 0.005,  = 0.946). For healthy fetuses, VI ranged approximately from 34.66% to 67.26% using the automatic ellipse method. The MP operative group exhibited significantly more cesarean deliveries (100% vs. 52.9%,  = 0.003), shorter gestational periods (34.76 ± 2.16 weeks vs. 37.48 ± 1.55 weeks,  < 0.001), lower birth weights (2762.14 ± 452.76 g vs. 3225.88 ± 339.98 g,  = 0.003), more persistent ascites (92.9% vs. 52.9%,  = 0.021), more frequent intestinal wall echo reductions (57.1% vs. 5.9%,  = 0.004), and lower VI (18.57 ± 5.51% vs. 39.41 ± 7.02%,  < 0.001). A predictive model was established: Logit (P)=8.86 - (0.37* VI) + (1.49* ascites), yielding an area under the curve of 0.857, with 78.6% sensitivity and 88.2% specificity. The VI value was significantly associated with the need for postnatal surgery (OR = 0.689, 95% confidence interval: 0.511 - 0.929,  = 0.015). A Receiver Operating Characteristic curve analysis for VI in predicting postnatal surgery showed an area under the curve of 0.971, with an optimal cutoff value of 35%, achieving 91% sensitivity and 94.4% specificity.

Conclusion: MV-Flow imaging effectively quantified fetal bowel wall blood flow perfusion. There was no significant change in VI across different gestational weeks. Significantly lower VI values in MP fetuses indicated an increased risk of intestinal wall necrosis and the potential need for postnatal surgical intervention.