GRADING SYSTEM FOR ECHOGENIC BOWEL (1)

Grade	Sonographic appearance	Frequency of associated abnormalities
0	Normal bowel echogenicity	0%
1	Echogenicity increased but less than the iliac crest	0%
2	Echogenicity similar to that of the iliac crest	5%
3	Echogenicity greater than that of the iliac crest.	46%

• Iliac crest is used as an internal standard as it can usually be imaged at the same level as the bowel.
• Increasing echogenicity (and therefore a higher grade) correlates with increased risk of a fetal abnormality.
• Bowel must be investigated with a 3.5 or 5.0Mhz transducer as some workers (2,3) have observed hyperechogenic bowel in normal fetuses when scanned with 6.5 or 8Mhz transducers.

Echogenic bowel – 7.5 MHz transducer

REFERENCES

1. Slotnick R, Abuhamad A. Prognostic implications of fetal echogenic bowel. Lancet 1996;347:85-87.
2. Perez CG, Goldstein RB. Sonographic borderlands in the fetal abdomen. Seminars in Ultrasound, CT, and MRI 1998;19(4):336-346.
3. Vincoff NS, Callen PW, Smith-Bindman R, Goldstein RB. Effect of ultrasound transducer frequency on the appearance of the fetal bowel. J Ultrasound Med 1999;18:799-803.