Prognostic implications of fetal echogenic bowel

Area of Science:

• Medical Imaging
• Prenatal Diagnostics
• Genetics

Background:

• Increased fetal echogenic bowel on ultrasound is linked to cystic fibrosis (CF) and trisomy-21.
• Previous diagnostic limitations were due to the lack of standardized echogenicity measurement.
• This study addresses the need for quantitative assessment of fetal bowel echogenicity.

Purpose of the Study:

• To develop and validate an ultrasonic grading system for fetal echogenic bowel.
• To assess the diagnostic utility of this grading system for identifying fetal genetic abnormalities.
• To determine the positive ascertainment rate of genetic testing in fetuses with echogenic bowel.

Main Methods:

• A novel ultrasonic grading system was devised, quantifying echogenicity by linear gain reduction and comparison with the fetal iliac crest.
• 145 fetuses with abnormally echogenic bowel were identified from 7400 second-trimester ultrasound referrals.
• Genetic counseling, carrier testing for CF, and amniocentesis for karyotype and CF status were offered.

Main Results:

• No cases of CF or aneuploidy were found in fetuses with mild echogenic bowel (grade 1).
• Moderate echogenic bowel (grade 2) was associated with trisomy 21 (2 cases) and CF (2 cases).
• Pronounced echogenic bowel (grade 3) showed a higher association with CF (5 cases) and trisomy-21 (6 cases).

Conclusions:

• The developed ultrasonic grading system effectively quantifies fetal bowel echogenicity.
• Grades 2 and 3 echogenic bowel in fetuses have a high positive ascertainment rate for genetic conditions like CF and aneuploidy.
• Parental CF carrier testing and amniocentesis are valuable tools for diagnosing fetal CF and aneuploidy when echogenic bowel is detected.