Diagnostic ultrasound ( PDFDrive )

CHAPTER 8 The Gastrointestinal Tract 297
A
B
C
FIG. 8.47 Small Bowel Edema Secondary to Vasculitis. (A) and (B)
Sonograms show marked edema of the valvulae conniventes of the entire
small bowel. (C) is a conirmatory CT scan with identical observations.
(With permission from Wilson S. Evaluation of the small intestine by
ultrasonography. In: Gourtsoyiannis N, editor. Radiologic imaging of the
small intestine. Heidelberg: Springer-Verlag; 2002. pp. 73-86. 18 )
Pseudomembranous colitis should be suspected in any patient with
difuse colonic wall thickening but without a previous history of
IBD. Because the history of concurrent or prior antibiotic therapy
is not always given, direct questioning of the patient is frequently
helpful.
Congenital Cysts
Duplication cysts, characterized by the presence of the normal
layers of the gut wall, can occur in any portion of the GI tract.
hese cysts may be visualized on sonogram, either routine or
endoscopic, and should be considered as diagnostic possibilities
whenever unexplained abdominal cysts are seen. Tailgut cysts
are variants of abdominal cysts that are seen in the presacral
region and are related to the rectum (Fig. 8.49).
Ischemic Bowel Disease
Ischemic bowel disease most oten afects the colon and is most
prevalent in older persons with arteriosclerosis. In younger
patients, it may complicate cardiac arrhythmia, vasculitis,
coagulopathy, embolism, shock, or sepsis. 12 Sonographic features
of ischemic bowel disease have been poorly described, although
gut wall thickening may be encountered. Pneumatosis intestinalis
may complicate gut ischemia with a characteristic sonographic
appearance.
Pneumatosis Intestinalis
Pneumatosis intestinalis is a relatively rare condition in which
intramural pockets of gas are found throughout the GI tract. It
has been associated with a wide variety of underlying conditions,
including chronic obstructive pulmonary disease, collagen
vascular disease, IBD, traumatic endoscopy, and post–jejunoileal
bypass. In many situations, afected patients are asymptomatic
and the observation is incidental. However, its demonstration
is of great clinical signiicance when necrotizing enterocolitis or
ischemic bowel disease is present. Both conditions are associated
with mucosal necrosis in which gas from the lumen passes to
the gut wall.
Sonographic description of pneumatosis intestinalis is limited
to isolated case reports. High-amplitude echoes may be demonstrated
in the gut wall, with typical air artifact or shadowing 89,90