50% contain ectopic gastric mucosa
90% present with GI bleeding in children
IMAGING
•
Rule of 2s
Seen in ∼ 2% of population
Located within 2 feet of ileocecal valve
Length of 2 inches (on average)
Symptomatic usually before age 2
2 main complications in adults: Diverticulitis (20%) and intestinal obstruction (40%)
•
CT: Meckel diverticulitis
Blind-ending pouch containing fluid, air, or particulate matter (including calculi)
Inflamed: Mural thickening of diverticulum and adjacent SB
Shows mural enhancement on CECT
Mesenteric fat infiltration and fluid
–
Extraluminal gas and lymphadenopathy in some cases
± partial or complete small bowel obstruction
± intussusception
–
Inverted diverticulum may form lead mass
TOP DIFFERENTIAL DIAGNOSES
•
Mesenteric adenitis and enteritis
CLINICAL ISSUES
•
Children: Present with GI bleeding before age 2
•
Adults: Present with diverticulitis or obstruction
(Left) Graphic shows a blind-ended outpouching 
from the antimesenteric border of the distal ileum, typical of a Meckel diverticulum.
(Right) Axial CECT shows enteroliths 
within a blind-ended sac in the right lower quadrant that proved to be a Meckel diverticulum at surgery.
(Left) Axial CECT in a 27-year-old man with RLQ pain shows calcified enteroliths 
lying within a blind-ending sac in the RLQ.
(Right) Surgery confirmed a Meckel diverticulum with mild chronic inflammation of the wall and multiple calcified enteroliths (shown here) within it.
TERMINOLOGY
Abbreviations
•
Meckel diverticulum (MD)
Definitions
•
Ileal outpouching due to persistence of omphalomesenteric or vitelline duct
IMAGING
General Features
•
Best diagnostic clue
Blind-ended sac or outpouching on antimesenteric border of distal ileum
•
Size
4-10 cm in length
•
Morphology
Tubular outpouching of ileum
•
Other general features
Most common congenital anomaly of GI tract
True diverticulum (contains all layers of bowel wall)
Arises from antimesenteric border of distal ileum
Formed by incomplete obliteration of ileal end of vitelline duct
Usually located within 50-60 cm of ileocecal valve
50% contain ectopic gastric mucosa
–
± pancreatic, duodenal, and colonic mucosa
90% of cases with bleeding contain gastric mucosa
Fibrous band (obliterated part of vitelline duct may connect apex of diverticulum to umbilicus)
Rule of 2s
–
Seen in ∼ 2% of population
–
Located within 2 feet of ileocecal valve
–
Length of 2 inches (on average)
–
Symptomatic usually before age 2
–
2 main complications in adults: Diverticulitis (20%) and intestinal obstruction (40%)
Radiographic Findings
•
Radiography
Radiograph A-P abdomen
–
Round collection of gas ± solitary or multiple calcified densities (enteroliths) within it in right lower quadrant (RLQ)
•
Fluoroscopic-guided enteroclysis
Superior due to maximum luminal distention
Blind-ended sac on antimesenteric border of ileum with either broad base or narrow neck
Broad-based diverticulum
–
Enteroclysis shows distinctive triangular junctional fold pattern at site of origin
Narrow neck diverticulum
–
Diagnosis depends on demonstration of blind end of diverticulum and its antimesenteric origin
Appears small initially but fills more completely with increased distention of lumen
Inverted Meckel diverticulum
–
Solitary, elongated, smoothly marginated, often club-shaped intraluminal mass parallel to long axis of distal ileum; may lead to intussusception
•
Double-contrast barium enema
Occasionally demonstrates MD by reflux into ileum
