Clinical presentation
Meckel’s diverticulum is usually asymptomatic.
Clinical symptoms arise from complications of the diverticulum in 2-4 % of patients such as :
Gastrointestinal bleeding :(Fig.1)
Gastrointestinal bleeding is common among adults and is caused by peptic ulcers of the diverticulum in the presence of heterotopic gastric mucosa.
Inflammation : diverticulitis/perforation/abcess(Fig.2-3)
Diverticulitis is a result of ulceration secondary to acid secretion from ectopic gastric mucosa.
In addition,
obstruction of a diverticulum by an enterolith and foreign body impaction also may lead to inflammation(Fig.4),
necrosis,
and eventual perforation.
small bowel obstruction :(Fig.5)
Intestinal obstruction may result from an inverted Meckel diverticulum,
with or without intussusceptions (the inverted meckel’s diverticulum acts like polypoid mass and thus causing intussusception); volvulus around fibrous bands; inflammatory adhesion; expulsion of enteroliths from the diverticulum
Rare neoplastic changes :
Neoplasms such as carcinoid tumor,
gastrointestinal stromal tumor,
and leiomyoma that arise from Meckel diverticulum are rare; however,
the most common such neoplasm is carcinoid tumor
Gastrointestinal bleeding is the most common complication in children with Meckel diverticulum,
whereas small bowel obstruction and diverticulitis are the most common complications in adults.
MDCT findings
At CT,
Meckel diverticulum may appear as a fluid- or air-filled blind-ending pouch that arises from the antimesenteric side of the distal ileum.
However,
CT has low sensitivity for the detection of uncomplicated Meckel diverticulum because its appearance resembles that of a normal bowel loop.
The diagnosis may be suggested if features of known complications of Meckel diverticulum are detected.
Such features are most often detected around the small bowel of the right lower quadrant or the mid lower abdomen.
For this reason,
the CT appearance of Meckel diverticulum often varies,
depending on the complications.Typical CT findings of Meckel diverticulum with complicating intestinal obstruction are isolated small bowel obstruction and intussusception with small bowel obstruction.
Inverted Meckel diverticulum that serves as a lead point for intussusception appears as a central area of fat attenuation surrounded by a thick collar of soft-tissue attenuation.
CT findings of volvulus resulting from fibrous bands and associated with small bowel obstruction are similar to those of isolated small bowel obstruction,
and it is difficult to differentiate between obstruction and fibrous bands or inflammatory adhesion in patients with volvulus at CT.
When Meckel diverticulitis is present,
CT depicts an inflammatory cystic mass attached to adjacent small bowel.
Inflammatory changes in the surrounding mesentery and adjacent fluid collections also help distinguish diverticulitis,
and calcification related to enteroliths may be seen within the inflamed diverticulum.
Neoplasms and heterotopic tissue in Meckel diverticulum appear as nodular or polyploid intraluminal masses that enhance on CECT.
Nuclear Medecine findings :
Tc-99m pertechnetate :
Most widely used method for diagnosing bleeding Meckel diverticulum.
Shows an accumulation of isotope in the right lower quadrant on positive scans.
Pentagastrin can be used to stimulate meckel diverticulum gastric mucosal uptake.
There are False-positive results such as appendicitis,
gastric ectopia,
inflammatory bowel disease ; and False negative results if the ectopic gastric mucosa is absent or minimal.
DIFFERENTIAL DIAGNOSIS :
Clinically the differential diagnosis is broad,
and unless a Meckel diverticulum is known to be present,
Meckel diverticulitis is usually not specifically suspected.
*Appendicitis
*Crohn Disease
*Mesenteric Adenitis and Enteritis
*Cecal Diverticulitis