Diagnostic ultrasound ( PDFDrive )

CHAPTER 53 The Pediatric Gastrointestinal Tract 1839
A
B
FIG. 53.9 Hypertrophic Pyloric Stenosis. (A) Echogenicity artifact at 6 and 12 o’clock positions (anisotropic effect). Cross-sectional image
through the pylorus shows the thickened muscle with increased echogenicity at 6 and 12 o’clock positions. (B) Posteriorly directed canal artifact.
Note the squared-off appearance of the gastric antrum (arrows). The thickened pylorus (P) is only partially visible in this imaging plane.
A
B
FIG. 53.10 Empty Stomach Artifact. (A) Before luid is administered, the antrum is contracted and the pyloric muscle appears thickened
(arrows). (B) When luid distends the antrum, the true normal thickness of the muscle is seen (arrows).
Gastric Diaphragm
he gastric diaphragm, or antral web, consists of a congenital
membrane that extends across the gastric antrum. hese diaphragms
most oten lie less than 2 cm from the pylorus and are
therefore usually visible on ultrasound examination. Complete
diaphragms are considered one form of gastric atresia, but many
diaphragms are incomplete and cause variable degrees of obstruction.
On sonography, the web appears as an echogenic band
across the distal gastric antrum (Fig. 53.11). Care must be taken
to image such webs in the true midlongitudinal plane because
if an incomplete diaphragm is imaged at its periphery, a complete
diaphragm may be erroneously suggested.
Gastritis and Ulcer Disease
Peptic ulcer disease in pediatric patients is probably more common
than generally is appreciated. 29 Gastric ulcers are more common
than duodenal ulcers in younger children (median age of 6.5
years) and Helicobacter pylori infection is less prevalent with
gastric ulcers than with duodenal ulcers. 29 Sonography is not
particularly helpful with duodenal ulcers, but gastric inlammatory
disease may be visible sonographically. Barium radiographic
studies oten reveal nothing more than persistent deformity or
spasm of the antropyloric region. Ultrasound of the luid-illed
stomach permits direct visualization of the thickened gastric
mucosa and submucosa, 30 which oten is accompanied by loss