Slotnick R N, Abuhamad A Z
Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk 23507, USA.
Lancet. 1996 Jan 13;347(8994):85-7. doi: 10.1016/s0140-6736(96)90210-x.
An increased frequency of hyperechogenic bowel on ultrasound has been reported in fetuses with cystic fibrosis (CF) and trisomy-21. However, the diagnostic application of this observation has been hampered by the absence of a means of measuring echogenicity.
We devised an ultrasonic grading system in which echogenicity was quantified by linear gain reduction and comparison with fetal iliac crest. From 7400 second-trimester ultrasound referrals, 145 patients were identified as having a fetus with abnormally echogenic bowel. They were offered genetic counselling, parental and (if appropriate) CF carrier testing, and amniocentesis for karyotype and CF status if parents were informative. Follow-up was to 4 months of age.
Of 40 fetuses with mild increase in bowel sonodensity (grade 1), none had CF or aneuploidy. Of 81 patients identified with a moderate increase (grade 2), 2 had trisomy 21 and 2 had CF. And of 24 pregnancies with a pronounced increase (grade 3), 5 had CF and 6 had trisomy-21.
Parental CF carrier testing and amniocentesis to identify aneuploidy or fetal CF status has a high positive ascertainment rate in fetuses with echogenic bowel grades 2 and 3.
