Diagnostic Ultrasound - Abdomen and Pelvis

Crohn Disease
Diagnoses: Bowel
TERMINOLOGY
• Chronic, relapsing granulomatous inflammatory disease
with predominant involvement of gastrointestinal tract
IMAGING
• Ultrasound
○ Bowel wall thickening
– Adults: > 3 mm
– Children: Small bowel thickness > 2.5 mm and large
bowel wall thickness > 2 mm
○ Loss of normal bowel wall stratification
○ Hyperemia of bowel wall correlates with disease activity
○ Thickening/increased echogenicity of mesentery
• Can occur anywhere from mouth to anus
• Involvement: Terminal ileum (95%), colon (22-55%), rectum
(14-50%)
• Look for skip lesions: Normal bowel between areas of
involved bowel
KEY FACTS
○ Fistulas (enteroenteric, enteromesenteric,
enterocutaneous, enterovesical, enterovaginal)
○ Phlegmon/abscess
• Undiagnosed or suspected patients stratified into high or
low risk based on symptoms, laboratory values, physical
exam, and family history
○ Low risk: Ultrasound or MRE recommended
○ High risk: MRE or CTE
• Newly diagnosed patients
○ MRE or CTE
DIAGNOSTIC CHECKLIST
• Penetrating &/or stricturing disease alters clinical
management
• Evaluate for associated abnormalities in other organs
(primary sclerosing cholangitis, arthritis, gallstones, and
urolithiasis)
(Left) Short-axis ultrasound of
the sigmoid colon shows
marked thickening ſt of the
wall and loss of normal
stratification. (Right) Longaxis
ultrasound shows marked
thickening ſt, loss of bowel
wall stratification, and luminal
narrowing in this 17 year old
with Crohn disease.
(Left) Grayscale long-axis
oblique ultrasound shows a
thickened terminal ileum ſt.
(Right) Color Doppler
ultrasound in the same patient
shows hyperemia ſt in the
terminal ileum compatible
with active inflammation.
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