Diagnostic ultrasound ( PDFDrive )

300 PART II Abdominal and Pelvic Sonography
A
B
FIG. 8.52 Peptic Ulcer. (A) Cross-sectional sonogram of the stomach shows a hypoechoic eccentric mass with a bright, central echogenic
focus representing air in the ulcer crater. (B) Conirmatory scan with barium swallow.
Bezoars
Bezoars are masses of foreign material or food, typically found
in the stomach ater surgery for peptic ulcer disease (phytobezoars)
or ater ingestion of indigestible organic substances such
as hair (trichobezoars). hese masses may produce shadowing
intraluminal densities on the sonogram and have been documented
as a rare cause of small bowel obstruction. 78 hey may
also form in the small bowel in association with chronic stasis.
Intraluminal Foreign Bodies
Large foreign bodies, including bottles, candles, sexual vibrators,
contraband, tools, and food, may be identiied in the GI tract,
particularly in the rectum and sigmoid colon, where they produce
fairly sharp, distinct specular echoes with sharp, acoustic shadows.
heir recognition is enhanced by suspicion of their presence.
Celiac Disease
Undiagnosed adult patients with celiac disease are encountered
infrequently in general ultrasound departments. Nonetheless, I
have occasionally seen patients in whom sonography is the irst
test to suggest the correct diagnosis. Sonographic observations
include abnormal luid-illed small intestine with moderate
dilation of the involved loops. Abnormal morphology is observed,
which Dietrich et al. 93 describe as a reduction in Kerckring plicae
circulares (valvulae conniventes) with loss of density and uniformity.
Peristalsis is increased above normal. An increase in
the caliber of the superior mesenteric artery and portal vein may
also be seen. 94
Cystic Fibrosis
Aggressive treatment of the pulmonary problems of cystic ibrosis
(CF) increases the likelihood of encountering adult patients in
a general ultrasound department that performs abdominal
sonography. hickening of the gut wall, particularly of the right
hemicolon and to a lesser extent the let colon and small bowel,
may be seen in association with iniltration of both the pericolonic
and the mesenteric fat. 95 hese may oten be incidental observations
without signiicant associated symptomatology. In advanced
CF, a ibrosing colonopathy with stricture may be seen. 96,97 he
culture of C. diicile is also documented in some patients with
CF and colon wall thickening, without the accompanying
symptoms of abdominal pain and diarrhea. 98 However, positive
stool culture is not the rule in CF patients with detectable colon
wall thickening.
ENDOSONOGRAPHY
Endoscopic sonography, performed with high-frequency transducers
in the lumen of the gut, allows for detection of mucosal
abnormality, delineation of the layers of the gut wall, and deinition
of the surrounding sot tissues to a depth of 8 to 10 cm from the
transducer crystal. hus tumors hidden below normal mucosa,
tumor penetration into the layers of the gut wall, and tumor
involvement of surrounding vital structures or lymph nodes may
be well evaluated. Staging of previously identiied mucosal tumors
is one of the major applications of endosonographic technique.
Upper Gastrointestinal Tract
Rotating, high-frequency transducers, using 7.5-MHz crystals
itted into a iberoptic endoscope, are most suitable for endosonography
of the esophagus, stomach, and duodenum. Light
sedation of the patient is usually required. he patient is placed
in the let lateral decubitus position and the endoscope inserted
to the desired location. Intraluminal gas is aspirated, and a balloon
covering the transducer crystal is inlated with deaerated water.
Localization is determined from the distance of insertion from