Diagnostic ultrasound ( PDFDrive )

CHAPTER 53 The Pediatric Gastrointestinal Tract 1843
A
B
FIG. 53.18 Midgut Volvulus. (A) The pylorus is widely patent and the proximal duodenum is dilated and shows vigorous peristalsis. The point
of obstruction is not clearly visible in this patient. (B) In a different child, vigorous peristaltic activity fails to empty the duodenum, and the third
portion of the duodenum has beak deformity (arrow). S, Stomach.
Small bowel obstruction from intestinal hematomas usually
occurs as a result of Henoch-Schönlein purpura, blunt abdominal
trauma, or coagulopathies. In any of these conditions, the
mural hemorrhage can be detected sonographically as asymmetric
or circumferential areas of intestinal wall thickening that can
vary from echogenic to hypoechoic. 53
FIG. 53.19 Midgut Volvulus “Whirlpool” Sign. Color Doppler
shows a clockwise whirlpool of vessels (arrows) around a volvulus.
Intussusception
Intussusception is the most common cause of small bowel
obstruction in children between the ages of 6 months and 4
years. Clinical indings of crampy, intermittent abdominal pain,
vomiting, palpable abdominal mass, and “currant jelly” stools
are classic. Patients with these characteristic symptoms probably
do not require ultrasound diagnosis before attempted enema
reduction. Many of these clinical features are present in young
children with abdominal pain for other reasons, and some children
with intussusception do not exhibit all the classic features. In
such children, sonography can help conirm or exclude intussusception.
Sensitivity and speciicity for the diagnosis of intussusception
with ultrasound are very high, approaching 100%. 56-60
If an intussusception is not demonstrated sonographically, an
enema need not be performed unless clinical suspicion is high.
False positives can occur occasionally in other conditions causing
thickened bowel wall 61 (Fig. 53.25).
calciications in the peritoneal cavity. In patients in whom larger
amounts of meconium have leaked, or in whom an active leak
remains ater birth, cystic masses can be found in the peritoneal
cavity, giving rise to the term cystic meconium peritonitis.
Sonographically, these cysts are of variable size and are fairly
well deined, oten with very heterogeneous cystic luid. 54,55 he
highly echogenic calciications can also be found with ultrasound
(Fig. 53.24). Echogenic ascitic luid may also be present ater
perforation, whether in utero or neonatal.
Sonographic Signs of Intussusception
Oval hypoechoic mass
Pseudokidney or doughnut sign
Hypoechoic rim with central echogenicity
Multiple layers and concentric rings
Small amount of peritoneal luid
Large amount of peritoneal luid suggests perforation,
especially echogenic ascites