Diagnostic ultrasound ( PDFDrive )

1836 PART V Pediatric Sonography
1 2
T
C
Pseudothick
Normal
Pseudothick
Normal
A
B
C
D
FIG. 53.4 Pyloric Muscle Tangential Imaging Artifacts. (A) When imaging the antrum in cross section, the muscle will appear thickened if
obtained through plane 1, but will show normal thickness if obtained through plane 2. (B) Longitudinal scan, tangential plane (T), shows pseudothickening.
Imaging in center (C) shows true normal muscle thickness. (C) Tangential scan shows muscle pseudothickening (arrows). D, Duodenum.
(D) Antrum distended with luid shows normal muscle (arrows).
soter, more pliable, and thinner. Rarely, HPS manifests during the
irst 14 days of life and can be challenging to diagnose because
most consider HPS to occur ater 2 weeks of age. hese infants
are oten thought to have severe relux, and ultrasound criteria
for these younger infants are also not established. hose with
presentation before the expected age range are more likely to
have a positive family history than those with presentation
ater 2 weeks of age, and more of these infants have been
breast fed. he muscle thickness is also decreased relative to
the older HPS patient, with some advocating a muscle thickness
of greater than or equal to 2.5 mm and channel length of
greater than or equal to 14 mm for criteria in these younger
patients. 23-25
Ultrasound also is very useful for the evaluation of persistent
vomiting in the postpyloromyotomy patient. he luoroscopic
upper GI series is of limited value in such cases because it tends
to show persistent deformity and narrowing of the canal even
in asymptomatic patients. However, sonography can deinitively
identify persistently thickened muscle, although cautious interpretation
in postpyloromyotomy patients is recommended because
the pyloric muscle may not reach its normal thickness until 8
months ater surgery 26 (Fig. 53.7).
Pylorospasm and Minimal Muscular Hypertrophy
In some vomiting infants, sonography shows a persistently
contracted and elongated canal, but the degree of muscular
thickening is less than the criterion of 3 mm for surgically correctible
HPS. With extended observation, eventually the canal
opens and luid is seen to pass into the duodenum, 27 but the
periods of spasm predominate (Fig. 53.8). In the vast majority
of cases, there is no thickening of the pyloric muscle or mucosa,
and the problem is primarily nonspeciic pylorospasm (antral