Meckel's Flashcards
purpose of Meckel’s scan
detect and localize meckel’s diverticulum or ectopic/heterotopic gastric mucosa
difference between ectopic and heterotopic gastric mucosa
ectopic: organ migrated
heterotopic: tissue at site of origin
symptoms of Meckel’s
- painless hematochezia
- presentation of GI bleed in child
- maybe tenderness at umbilicus
what are other causes of heterotopic gastric mucosa
- gastrointestinal duplications
- post-operative retained gastric antrum
- Barrett’s esophagus
where are meckel’s usually found?
LRQ in distal ileum
meckel’s diverticulum is usually caused by…
remnant of fetal omphalomesenteric duct causing outpouching
what are the 4 rules of 2?
- present in 2% of population
- 2cm outpouching
- 2 feet from ileocecal value
- usually diagnosed by 2 yo
if obstruction is present, what are the symptoms?
abdominal pain, bloating and nausea
treatment for Meckel’s
bowel/diverticulum resection
RP and dose
pert at 296-444 MBq (adults)
or 1.85 MBq/kg for peds
patient prep
- npo for 2-4 hours
- good hydration
- pharm pre-treatment
- d/c thyroid blocking meds for 48 hrs
what does cimetidine do?
inhibits gastric secretions and enhances pert accumulation
how does cimetidine do that?
it is antagonist to histamine H2 receptors
dose of cimetidine for adults
300 mg, po
given 2 days prior
dose of cimetidine for kids
10-20 mg/kg/day for two days prior
what is the other pharm that does the same thing as cimetidine?
ranitidine
dose of zantac for kids
1 mg/kg up to 50 mg max
slow IV infusion over 20 mins
dose of zantac for adults
150-300 mg po
2-3 hours prior
what does glucagon do?
decreases peristalsis in bowel = stasis of secreted pert
what is glucagon usually coupled with?
pentagastrin
dose of glucagon
50 ug/kg to 1 mg/kg IV
imaging time when using glucagon
10 mins prior or 10 mins post pert admin
what does pentegastrin do?
stimulates gastric secretions = increase rate of TcO4- uptake from blood
another name for pentegastrin
peptavalon
another name for Ranitidine
zantac
dose of pentegastrin
6 ug/kg SQ
imaging time with pentegastrin
5-20 mins prior to pert admin
fov for meckel’s study
abdomen and pelvis (including stomach and bladder)
pos for meckel’s
- focal area of increased uptake in abdomen (ant LRQ)
- uptake increases over time
- same timing and intensity as stomach
- appears prior to bladder activity
normal appearance for meckel’s
cardiac blood pool, large vessels that decrease over time, hepatic and splenic pool, stomach (increase over 10-20 mins then decreases over time), early renal activity, collecting system, scrotal/testicle activity
false positives
- *urinary tract activity
- aneurysms, AVM, hemangioma
- bowel inflammation
- neoplasms
- ulcers, Crohns disease, colitis, peptic ulcer
- intussusception
- barium enema
false negatives
- minimal gastric mucosa, small diverticula
- rapid washout
- competing meds
what other pathologies can be identified with NMT pert scintigraphy?
- gastrointestinal duplications
- retained gastric antrum
- Barrett’s esophagus imaging
method of localization
active transport
critical organ
large bowel
what are pharm pre-treatments used for?
to improve the sensitivity of the study
false positives
- inflammatory or obstructive lesion in GI
- vascular lesions
- normal excretion in GI or urinary tract
- ectopic gastric mucosa
- recent colonoscopy or laxatives
false negs
- small, no gastric mucosa
- necrotic mucosa
- rapid peristalsis
- recent barium or perchlorate
