meckel diverticulum

Technetium-99m
(99mTc) pertechnetate "Meckel"s Scan" with radiotracer activity (black) becoming more intense over time (from top left to bottom right) at the stomach and right lower quadrant, indicating a Meckel"s diverticum with gastric mucosa.
Wikipedia • CC BY-SA 4.0
School ager
with massive lower GI bleeding. AP and lateral images from a Technetium-99m Meckel scan (above left) show no areas of abnormal uptake of radiotracer in the abodmen. Axial CT with contrast of the abdomen (above right) shows a small, round, primarily solid soft tissue mass just to the right of the midline between the loops of bowel that on coronal (below left) and sagittal (below right) images is seen to be tubular in appearance and connecting to the anterior abdominal wall near the umbilicus.The diagnosis was Meckel diverticulum.
pediatricimaging.org • CC-by-nc-sa 4.0
Meckel
diverticulum • Small bowel obstruction due to internal hernia associated with Meckel's diverticulum - Ganzer Fall bei Radiopaedia
Kumar K, Small bowel obstruction due to internal hernia associated with Meckel's diverticulum. Case study, Radiopaedia.org (Accessed on 13 Jul 2023) https://doi.org/10.53347/rID-164039 • CC by-nc-sa 3.0 (modified)
Meckel
diverticulum • Small bowel obstruction due to internal hernia associated with Meckel's diverticulum - Ganzer Fall bei Radiopaedia
Kumar K, Small bowel obstruction due to internal hernia associated with Meckel's diverticulum. Case study, Radiopaedia.org (Accessed on 13 Jul 2023) https://doi.org/10.53347/rID-164039 • CC by-nc-sa 3.0 (modified)
Meckel
diverticulum enterolith complicated with diverticulitis. Diffusely distended small bowel loops filled with fluid. Calcification with entrapped gas, surrounded by soft tissue with signs of inflammation in lower quadrants.
www.eurorad.org • CC by-nc-sa-4.0
Toddler with
drainage of stool from the umbilicus. AP delayed image (left) from a Tc-99m pertechnetate scan (Meckel’s scan) shows a focal round concentration of radiotracer in the right lower quadrant superior and lateral to the midline bladder which is seen in the middle of the lower abdomen superior to the bladder on the lateral (right) delayed image.The diagnosis was Meckel’s diverticulum with a patent omphalomesenteric duct.
pediatricimaging.org • CC-by-nc-sa 4.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 39-year-old woman with surgically proven ileal intussusception related to the Meckel’s diverticulum as the lead point. a Intravenous- and oral-enhanced CT scan shows the intussusception of the ileum (arrow) along with its mesentery (asterisk), creating the “target sign.” b Image at a lower level than a demonstrates the invaginated mesenteric fat (arrow), along with thickening of the intussuscepted ileum (arrowhead).
insightsimaging.springeropen.com • CC-by-2.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 63-year-old patient with small bowel obstruction due to inflammation of the Meckel’s diverticulum (surgery proven). Intravenous abdominal CT shows the diverticulum as an enhancing, blind-ending digestive structure, with thick wall and fluid content (arrow); this finding was demonstrated to be an inflamed Meckel’s diverticulum situated at the transition point with the dilated small bowel loops and surrounded by inflammatory changes in the mesenteric fat.
insightsimaging.springeropen.com • CC-by-2.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 22-year-old man with massive gastrointestinal bleeding due to heterotopic gastric mucosa in a Meckel’s diverticulum (surgery proven). a Nonenhanced CT scan at the same level as b shows no spontaneously dense material in the bowel lumen. b Intravenous-enhanced CT scan shows contrast extravasation seen as linear hyperattenuating pooling of contrast at the neck of the Meckel’s diverticulum (arrow), arising from a distal ileal loop.
insightsimaging.springeropen.com • CC-by-2.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 22-year-old woman with surgically proven perforated Meckel’s diverticulitis and Crohn’s disease. Intravenous- and oral-enhanced CT shows the collection due to the perforated Meckel’s diverticulum (arrow) in the right lower quadrant. Thickened-wall ileal loops (arrowheads) and prominently dilated mesenteric vessels (asterisk), proving active Crohn’s disease are also demonstrated.
insightsimaging.springeropen.com • CC-by-2.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 32-year-old woman with surgically proven Meckel’s diverticulitis. a Intravenous- and oral-enhanced CT shows the inflamed diverticulum as a round, contrast-filled, thickened-wall collection (arrowheads) in continuation with an ileal loop; associated fat stranding (asterisk) is also demonstrated. b CT scan at a higher level than a shows the peridiverticular inflammatory changes (arrowheads) along with normal aspect of the appendix (arrow) and of the ileal loops proximal to the inflamed diverticulum (double arrows).
insightsimaging.springeropen.com • CC-by-2.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 44-year-old man with surgically proven necrotic Meckel’s diverticulum (images courtesy of Dr. K. Bider and Dr. C. Beynon). a Intravenous-enhanced CT shows the inflamed diverticulum as an air-fluid collection (arrow) with thin, nonenhancing wall adjacent to an ileal loop. b Photograph taken during surgery before opening the specimen shows a 7 cm large, necrotic Meckel’s diverticulum.
insightsimaging.springeropen.com • CC-by-2.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 33-year-old woman with surgically proven perforated Meckel’s diverticulum. a Intravenous- and oral-enhanced CT shows the perforated Meckel’s diverticulum as a gas-containing collection in the right lower quadrant (asterisk), situated between the ileal loops and surrounded by fat stranding (arrow). b Coronal reconstructed CT demonstrates the perforated diverticulum (asterisk), contiguous with a thickened ileal loop (arrow).
insightsimaging.springeropen.com • CC-by-2.0
School ager
with nausea and vomiting. AXR supine (upper left) and coronal CT with contrast of the abdomen (lower left) show multiple dilated loops of small bowel with thin walls throughout the abdomen. The lower axial CT (upper right) shows a small cystic structure in the midline with a thicker wall than the surrounding dilated bowel which is also seen on the midline sagittal CT (lower right) just beneath the umbilicus.The diagnosis was distal small bowel obstruction due to Meckel’s diverticulum.
pediatricimaging.org • CC-by-nc-sa 4.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 37-year-old man with inflamed Meckel’s diverticulum and abscess formation (surgery proven). Intravenous- and oral-enhanced CT scan shows a contrast-filled tubular diverticulum with a “mucosal triangular plateau” pattern at its ileal attachment (curved arrow); there is a fluid-filled collection at the diverticulum’s tip and associated fat stranding (arrowhead).
insightsimaging.springeropen.com • CC-by-2.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 76-year-old patient with surgically proven Meckel’s diverticulitis. Intravenous contrast-enhanced CT shows the Meckel’s diverticulum as a fluid-filled, blind-ending digestive structure (arrow), arising from a distal ileal loop, along with peridiverticular mesenteric fat stranding (asterisk), suggestive of inflammation.
insightsimaging.springeropen.com • CC-by-2.0
Intussuscepted
Meckel diverticulum. Coronal reformatted CT, showed small bowel distention, and ileocolic intussusception with a central core of fat density suggesting an intussuscepted, inverted Meckel diverticulum.
www.eurorad.org • CC by-nc-sa-4.0
Meckel
diverticulum enterolith complicated with diverticulitis. Calcification with entrapped gas, surrounded by soft tissue with signs of inflammation in lower quadrants.
www.eurorad.org • CC by-nc-sa-4.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 71-year-old woman with surgically proven inflamed Meckel’s diverticulum with tip perforation. Intravenous- and oral-enhanced CT shows the diverticulum as a tubular, thickened-wall, blind-ending digestive structure (asterisk) surrounded by an important fat infiltration (arrowheads); the diverticulum is situated in the right lower quadrant. Caecum and terminal ileum are normal (arrow).
insightsimaging.springeropen.com • CC-by-2.0
Computed
tomography of complicated Meckel’s diverticulum in adults: a pictorial review. A 20-year-old woman with surgically proven needle retention in a giant Meckel’s diverticulum. Oral-enhanced CT shows the needle (arrow) located at the collar of a fluid-filled, blind-ended tubular structure (asterisk) that is the Meckel’s diverticulum.
insightsimaging.springeropen.com • CC-by-2.0
Infant with
bilious vomiting and abdominal distension. AXR upright (left) shows multiple dilated loops of small bowel with air fluid levels. Sagittal US of the abdomen (above right) shows multiple dilated loops of peristalsing small bowel, however an intussusception was not seen. AP image from an upper GI exam (below right) shows the duodenal-jejunal junction to be low in position and to be to the right of the spine.The diagnosis was Meckel diverticulum causing a small bowel obstruction and a false positive diagnosis of malrotation with midgut volvulus due to displacement of the duodenal-jejunal junction by dilated loops of small bowel.
pediatricimaging.org • CC-by-nc-sa 4.0
Radiopaedia • CC-by-nc-sa 3.0 • de

Meckel diverticulum is a congenital intestinal diverticulum due to fibrous degeneration of the umbilical end of the omphalomesenteric (vitelline) duct that occurs around the distal ileum. It is considered the most common structural congenital anomaly of the gastrointestinal tract.

Epidemiology

Approximately 2% (range 0.3-3%) of all individuals may have a Meckel diverticulum (see the rule of 2s). While traditionally described to have increased male predilection, it may occur with equal frequency in both sexes although symptoms from complications are more common in male patients . Most patients with a complication are thought to present in the first two years of life .

Clinical presentation

A large proportion of individuals remain asymptomatic although up to a third of them may experience clinical symptoms.  The incidence of complications with a Meckel diverticulum is reported to wide range between 4% and 40% of patients; however, one retrospective study showed the lifetime risk of developing complications of the Meckel diverticulum is 4% up to the age of 20 years, 2% up to the age of 40 years, and zero in the elderly population . There is an increased incidence of the Meckel diverticulum in Crohn patients compared to the general population:

  • gastrointestinal hemorrhage (melena/hematochezia): most common complication and may account for ~30% of symptomatic cases . Large mostly self-limiting bright red rectal bleed.
  • small-bowel obstruction: second most common presentation
    • adhesion or mesodiverticular band
    • luminal obstruction from diverticulitis or foreign body impacted in the diverticulum or enterolith formation
    • volvulus
    • intussusception: particularly if the diverticulum inverts
    • internal hernia from a persistent attachment of the diverticulum to the umbilicus by the obliterated omphalomesenteric duct
    • Littre hernia: inclusion of the diverticulum into a hernia
    • neoplastic obstruction
    • inclusion of a Meckel diverticulum in a true knot that forms between the ileum and sigmoid.
  • inflammation (diverticulitis): Meckel diverticulitis
  • perforation
  • neoplasm arising in a Meckel diverticulum

Pathology

Gross anatomy

Meckel diverticulum is a true diverticulum (i.e. all layers of the gastrointestinal tract are present in its wall) and arises from the antimesenteric border of the small intestine.

It can be as long as 5 cm with diameters up to 2 cm. Most (75%) Meckel diverticula are found within 60 cm (range 40-100 cm) of the ileocecal valve . It can be seen in the midline, or on either side of the midline. However, midline and right iliac fossa location are the commonest. Its level on CT can be either superior or inferior to the terminal ileum .

Blood supply
  • arterial supply typically arises from the omphalomesenteric artery (arising from an ileal branch of the superior mesenteric artery)
Histology

Meckel diverticula are lined with heterotopic mucosa in up to 60% of cases:

  • gastric mucosa ~62%
  • pancreatic ~6%
  • gastric and pancreatic ~5%
  • jejunal ~2%
  • Brunner glands ~2%
  • gastric and duodenal ~2%
Development

It is considered a remnant of the omphalomesenteric-vitelline duct, which connects the yolk sac to the midgut through the umbilical cord. This duct is typically obliterated by the 5-8 week of gestation. Failure of closure results in:

Radiographic features

Imaging these may occasionally be detected incidentally or may be identified if there is a complication.

Fluoroscopy

Small bowel enemas have sometimes been used for the diagnosis in some centers, although a precise technique is required if the diagnosis is to be excluded with any degree of certainty .

Ultrasound

Usually of limited use in the diagnosis of an uncomplicated Meckel diverticulum. Ultrasound may show a blind-ending peristaltic loop connected to the small bowel.

CT

CT is of limited value in uncomplicated cases, as the diverticulum may resemble a normal bowel loop. CT may show a fluid- or air-filled blind-ending pouch that arises from the antimesenteric side of the distal ileum.

It is possible for the diverticulum to invert and appear as an intraluminal polypoid lesion .

Angiography or CT angiography

When investigated in the context of gastrointestinal hemorrhage, angiography/CT angiography may show the persistent omphalomesenteric artery in most individuals with a Meckel diverticulum although recognition of the artery may be difficult due to overlying vessels.

Scintigraphy

Scintigraphy with Tc-Na-pertechnetate has a limited sensitivity (~60%) ; however, it aids in the diagnosis of diverticula with ectopic gastric mucosa. Pertechnetate is taken up by mucin-secreting cells of the gastric mucosa and ectopic gastric tissue. Higher sensitivity may be present in children (~85-90%).

History and etymology

It is named after the German anatomist Johann Friedrich Meckel (the younger), (1781-1833) who described its anatomy and embryology in 1809 .

Siehe auch:
und weiter:
Assoziationen und Differentialdiagnosen zu Meckel-Divertikel:
Divertikulitis
 
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Appendicitis
epiploica
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Appendizitis
 
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Dünndarmdivertikulitis
 
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