Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

322 Small Animal Radiolo g y and Ultrasono graphy
Fig. 3-87 A 10-year-old female
Miniature Schnauzer with a 1-week
history of vomiting. There is an
irregularly shaped tissue-dense mass
in the pylorus on all ventrodorsal
views of this series (white arrows).
Differential diagnoses include
polyps, leiomyosarcoma, or granulomas.
Diagnosis: Pyloric polyps.
Fig. 3-88 A 4-year-old female Poodle with projectile vomiting for 3
weeks. The ventrodorsal view shows a round donut-shaped ring of
muscular hypertrophy at the pylorus that is covered with a minimal
amount of barium. The narrowed pyloric outflow tract is also visible
as a faint, narrow stream of barium extending rostrally (black arrow).
These findings were present on all ventrodorsal views. Differential
diagnoses include pyloric muscular hypertrophy, neoplasia, or granuloma.
Diagnosis: Pyloric muscular hypertrophy.
near the pyloric sphincter (Fig. 3-87). These may function as a ball valve causing the outflow
obstruction. Hypertrophy of the muscular layer of the pylorus and proximal duodenum
may not be apparent radiographically. However, concentric rings of hypertrophy,
which appear as circular, smooth, ridgelike filling defects encircling the pyloric outflow
region with the lumen and coming to a sharp point known as the parrot’s beak sign, may be
identified (Fig. 3-88). Hypertrophy of the gastric mucosa may not be identifiable radi-