Diagnostic Ultrasound - Abdomen and Pelvis

Intussusception
Diagnoses: Bowel
TERMINOLOGY
• Invagination or telescoping of 1 segment of
gastrointestinal tract and its mesentery (intussusceptum)
into lumen of adjacent distal segment (intussuscipiens)
IMAGING
• "Bowel within bowel" appearance
• Occurs anywhere from stomach to rectum
• Ultrasound: High sensitivity (98-100%) and specificity (88-
100%); first-line in children
• Concentric parallel rings of bowel wall (target, doughnut, or
bull's-eye sign)
• Layering of fluid trapped between compressed bowel
segments
• Signs of vascular compromise with reduced or absent mural
vascularity of intussusceptum; indicates risk of
ischemia/infarction and perforation
KEY FACTS
TOP DIFFERENTIAL DIAGNOSES
• Tumor, inflammation, infection
PATHOLOGY
• Children: Idiopathic in 95%
• Adults: Identifiable etiology in 90%, lead point, or
underlying condition such as celiac or Whipple disease
• Transient intussusception: Nonobstructing, spontaneous
resolution
CLINICAL ISSUES
• Children: Acute pain, palpable mass, "red currant jelly"
stools
• Adults: Insidious, vague abdominal symptoms, vomiting,
red blood in stool
• Complications: Obstruction, bowel ischemia, or infarction
• Surgery indicated where lead point identified or
complications evident on CT
(Left) Graphic shows ileo-colic
intussusception. Note entering
layer ſt, returning layer ,
and apex of
intussusceptum (terminal
ileum). Intussuscipiens (cecum)
and neck of
intussusception st are noted.
(Right) Transverse
transabdominal US shows
classic "bowel within bowel"
appearance of ileocolic
intussusception. Note the
inner intussusceptum (ileum
and mesentery ) and
outer intussuscipiens
(hypoechoic layer of
edematous bowel ſt) and
intervening fluid .
(Left) Longitudinal
transabdominal US shows the
layers of bowel wall involved
in the intussusception. Outer
layer of edematous bowel wall
(intussuscipiens) and
compressed inner layers st
(intussusceptum) are noted.
(Right) Longitudinal color
Doppler US shows
intussusception. Hyperemia of
edematous outer
intussuscipiens and inner
layers of intussusceptum st is
noted. Presence of vascularity
is favorable for bowel viability
and potential reducibility.
(Courtesy V. Godhamgaonkar,
MD.)
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