Meckel's Diverticulum

What is the patient prep?

-NPO 2-4 hours (preferable but not essential) -NPO (children)- normal feeding time minus 30 minutes -no barium within 3-4 days prior

What are some pharmaceutical interventions that help with detection of meckels?

-cimetidine (Tagamet) -pentagastrin (peptavin) -glucagon

What are abnormal results (positive for meckel's)?

-focal area of increased activity, usually in the RLQ -activity in meckel's appears at the same time as gastric mucosa, but remains despite peristalsis (doesn't move)

What is the general protocol?

-inject the patient *NOT a flow study -place the pt under the camera and take 30 minute anterior images -have patient void -take a 5 minute AP and lateral views

What radiopharmaceutical is used for this study?

Tc-99m TcO4- (pertechnetate)

What is a meckel's diverticulum?

a congenital abnormality that affects 2-3% of the population. a saclike pouch or bulge on the small intestine. it is a common cause of GI bleeding in children. usually seen in the RLQ. this outpouching of the intestinal wall can contain gastric mucosa (cells that act like stomach cells)

What is the MOL?

active transport

Why do meckel's diverticulum need to be addressed?

the diverticulum can become infected (diverticulitis), cause an obstruction of the intestine and/or cause bleeding from the intestine

How does cimetidine (Tagamet) work to improve detection?

-histamine H2 receptor antagonist -it inhibits the release of the radio tracer from the gastric mucosa by inhibiting/blocking gastric acid secretion, improving the lesion to background ratio

What are some indications for the study?

-localize ectopic gastric mucosa as a source of unexplained GI bleeding -evaluation of a patient with positive guaiac test (blood in feces) -evaluation of a patient with abdominal pain, cramping, tenderness near navel, bowel obstruction or swelling of intestinal wall (children)

What is the general rule of the 2's?

-occurs in only 2% of the population -occurs within 2 feet of the ileocecal valve (where the small and large intestine connect) -average length of 2 inches -usually symptoms appear by age 2

How does pentagastrin (peptavin) work to improve detection?

-potential stimulator of gastric mucosa uptake of TcO4- by stimulating gastric mucosa blood flow -procedure: 1)patient NPO 8 hours 2) inject pentagastrin (peptavin) 15 minutes before TcO4- administration

How does glucagon work to improve detection?

-relaxes the smooth muscles of the GI tract and decreases small bowel motility -reduces gastric secretions -prevents the washout of TcO4- from the stomach and the meckel's -usually used with pentagastrin (peptavin) to enhance the effects of pentagastrin (peptavin)

What is the dose for both adults and children?

adults: 10-15mCi children: 200uCi/kg

Are the majority of patients symptomatic or asymptomatic?

asymptomatic

How does the presence of ectopic gastric mucosa affect the meckel's?

ectopic gastric mucosa produces gastric acid which can cause ulceration and hemorrhage

What HAS to be present for a meckel's diverticulum to be visualized?

ectopic mucosa must be present for visualization. more sensitivity and specificity in children, as prevalence of ectopic gastric mucosa declines with age

What is the biodistribution?

it accumulates in normal and ectopic gastric mucosa. mucous cells of the gastric epithelium, when present in the diverticulum, accumulate and excrete the pertechnetate