Intestinal Hyperechogenicity Confirmed by Evaluation of Gray Spectra

Hyperechoic bowel is an ultrasound anomaly observed in screening and diagnostic ultrasound, and associated with various fetal pathologies including cystic fibrosis, chromosomal abnormalities, maternal-fetal infections (notably Cytomegalovirus CMV) and intrauterine growth retardation. Suspicion of hyperechogenic intestines in a fetus during a screening ultrasound leads to referral of the mother to a specialized antenatal diagnostic consultation. If the diagnosis is confirmed, this may lead to further investigations, including genetic analyses, which are costly for the healthcare system. However, many of the patients referred after a screening examination for this reason actually have their diagnosis invalidated during the specialized consultation. These "false alarms" lead to an overload of specialist consultations, and are a source of concern for couples.

. However, many of the patients referred after a screening examination for this reason actually have their diagnosis invalidated during the specialist consultation. These "false alarms" lead to an overload of specialist consultations, and are a source of concern for couples.

The diagnosis of intestinal hyperechogenicity is difficult because it is based on the sonographer's subjective impression, with a 3-grade gradation according to the echogenicity of the intestine in relation to the bone (Slotnick and Abuhamad. 1996). According to this method, the evaluation is carried out by progressively decreasing the gain applied to the image: if the hyperechoic bowel disappears before the iliac bone, it's a grade 1; if the bowel and iliac bone disappear at the same time, it's a grade 2; and finally if the bowel is still visible on the image while the iliac bone has disappeared, it's a grade 3.

In addition to gain, which, if too high, tends to overestimate the diagnosis of hyperechoic bowel, other ultrasound parameters can vary the subjective impression of bowel echogenicity, such as the use of high-frequency probes or the application of harmonics, which also lead to overdiagnosis (Lee and Cho. 2003).