Fetal echogenic bowel: what is real echogenicity?A quantitative method based on histogram analysis of the grayscale

Introduction: The aim of this study was to use computerized analysis of the grayscale spectrum (histogram) to provide an objective assessment of the echogenicity of the fetal bowel. Moreover, we investigated the role of histogram analysis in the prenatal prediction of postnatal outcomes in fetuses with echogenic bowel (FEB). Methods: This is a single-center retrospective study including all fetuses with a diagnosis of echogenic bowel (FEB) in the mid-second trimester between 2015 and 2021. Ultrasound images were analyzed using ImageJ software. The mean of the grayscale histograms of bowel, liver, and iliac/femur bone was obtained for each patient and the ratio between these structures was used to overcome gain variations. We compared these values with those of a matched control group of singleton uncomplicated pregnancies and with a group of patients referred for FEB, where the FEB was not confirmed by the expert operator (FEB false positive, FEBfp). Results: There was a statistically significant difference between Bowel/Liver and Bowel/Bone histogram ratios between the FEB group and the control groups (p<0.05). Mean ratio cut-offs were provided for the diagnosis of FEB. Among the patients with confirmed FEB, both ratios were not able to discriminate the cases with adverse outcomes. In contrast, the presence of dilated bowel or other markers was associated with an adverse outcome. Conclusions: Histogram analysis may refine the diagnosis of FEB and reduce the number of false positive diagnoses. For the prediction of fetal outcome, the presence of additional features is clinically more significant than the degree of bowel echogenicity.

Automated summary

This study aims to objectively assess the echogenicity of the fetal bowel using computerized analysis of the grayscale spectrum (histogram) and investigate its role in predicting postnatal outcomes in fetuses with echogenic bowel. The results show that histogram ratios can aid in diagnosing echogenic bowel and reduce false positive diagnoses. Additionally, the presence of additional features is more clinically significant in predicting fetal outcomes than the degree of bowel echogenicity.