Intussusception

Published on 19/07/2015 by admin

Filed under Radiology

Last modified 19/07/2015

Print this page

rate 1 star rate 2 star rate 3 star rate 4 star rate 5 star
Your rating: none, Average: 0 (0 votes)

This article have been viewed 1909 times

 Outer layer = intussuscipiens; inner layer = intussusceptum

image “Coiled spring” appearance on small bowel follow-through or enteroclysis
• CT: Alternating layers of mesenteric fat and soft tissue density bowel walls

image Enhancing mesenteric vessels accompany intussusceptum
image CT may identify lead mass
image Short segment, nonobstructing intussusceptions  are commonly seen, rarely significant
• US: “Target,” “doughnut,” or bull’s-eye sign

TOP DIFFERENTIAL DIAGNOSES

• Primary bowel tumor
• Metastases and lymphoma
• Endometrial implant
• Meckel diverticulum

PATHOLOGY

• Tumor-related lead point

image Benign: Polyp, leiomyoma, lipoma
image Malignant: Primary (more common in colon), metastases and lymphoma (more common in SB)
• Physical cause, but no neoplasm

image Postoperative causes are most common (e.g., adhesions, anastomoses)
• Intussusception in children

image Usually attributed to lymphoid hyperplasia in distal SB

CLINICAL ISSUES

• Obstruction and ischemia are more common in long-segment intussusception with lead mass
image
(Left) Graphic shows an ileocolic intussusception with a tumor in the bowel wall image as the lead mass. Note the vascular compromise and ischemia of the intussusceptum image.

image
(Right) Coronal CECT shows invaginated mesenteric fat image and vessels image from an ileocolonic intussusception. The lead mass proved to be carcinoma.
image
(Left) Transverse color Doppler ultrasound of SB intussusception shows vascular flow within an intraluminal mass image and 2 echogenic submucosal rings representing intussusceptum image and intussuscipiens image.

image
(Right) Transverse power Doppler ultrasound in the same patient reveals marked hyperemia image within the mass, which proved to be a metastatic melanoma.

TERMINOLOGY

Definitions

• Invagination or telescoping of proximal segment of bowel (intussusceptum) into lumen of distal segment (intussuscipiens)

IMAGING

General Features

• Best diagnostic clue

image Bowel-within-bowel, “coiled spring” appearance
• Location

image Ileoileal > ileocolic > colocolic
image Usually small bowel (SB) in adults, ileocolic in children
image Colon: Malignant tumors more common than benign
image SB: Benign tumors more common than malignant

Radiographic Findings

• Radiography

image Air-fluid levels, proximal bowel dilatation, absence of gas in distal collapsed bowel

Fluoroscopic Findings

• Barium study

image Classic “coiled spring” appearance

– Trapping of contrast between folds of intussusceptum and intussuscipiens
image Bowel obstruction, proximal dilatation, distal collapsed loops

CT Findings

• “Bowel-within-bowel” appearance

image Outer layer represents intussuscipiens, inner layer represents intussusceptum
image Alternating layers of mesenteric fat and soft tissue density bowel walls
image Enhancing mesenteric vessels accompany intussusceptum
• Reniform or sausage-shaped mass
• Features of intestinal obstruction

image Air-fluid levels, proximal bowel distension
image Obstruction and ischemia are more common in long-segment intussusception with lead mass

– CT may identify lead mass
• Short segment, nonobstructing intussusceptions 

image Commonly seen on CT
image Usually of no clinical significance

MR Findings

• “Bowel-within-bowel” or “coiled-spring” appearance
• Best seen on turbo spin-echo T2WI

Ultrasonographic Findings

• Grayscale ultrasound

image Transverse US: “Target,” “doughnut,” or bull’s-eye sign

– Peripheral hypoechoic halo: Edematous wall of intussuscipiens
– Intermediate hyperechoic area: Space between intussuscipiens and intussusceptum
– Internal hypoechoic ring: Wall of intussusceptum
image Longitudinal US: Pseudokidney or hay fork sign

– Multiple, thin, parallel, hypoechoic and echogenic stripes
• Color Doppler

image Mesenteric vessels dragged between entering and returning wall of intussusceptum

Imaging Recommendations

• Best imaging tool

image Depends on patient age/presentation
image Sonography may be sufficient for diagnosis in children

Buy Membership for Radiology Category to continue reading. Learn more here