Three-dimensional ultrasonographic technology to assess and compare echodensity of fetal bowel, bone, and liver in the second trimester of pregnancy

Increased fetal bowel echogenicity in the second trimester is used as a marker for prenatal diagnosis of Down syndrome. The diagnosis of hyperechogenicity is subjective. We sought to quantify and correlate fetal bowel echogenicity with liver and bone in 47 normal fetuses, using three- dimensional ultrasonographic technique and objective measurement of gray scale distribution. No significant change was found in the organs' echogenicity between 15 and 24 weeks of gestation, the optimal time for detection of fetal chromosomal anomalies. A wide variability in bowel density was noted within the normal group, which could explain its poor sensitivity for the detection of Down syndrome. Bowel echodensity correlates better with liver density than with bone density. Thus, comparison of bowel to liver echogenicity, even with two-dimensional sonography, may prove to be a more effective clinical tool in the evaluation of fetal intraabdominal echodensities.