Gastric Emptying Flashcards
indications
- rate of gastric emptying
- quantitate gastric function and motility
- response to therapy
patient prep
- NPO min 4 hrs
- good diabetic control
- d/c non-gastric therapeutic drugs for 48-72 hrs
- d/c prokinetic agents 48hrs
- no smoking morning of and throughout the test
examples of pro kinetic agents
- Metoclopramide (Reglan)
- Domperidone (Motilium)
- Cisapride (Propulsid)
- Erythromycin (Motilin Agonist)
RP and dose for SOLID gastric emptying
99mTc-SC
18.5-38 MBq
RP and dose for LIQUID gastric emptying
99mTc-SC or DTPA
or 111In-DTPA
37 MBq
what’s considered standardized meal?
- 2 toasts
- 30 g jam
- 4 oz egg whites
- 100 ml water
SC and eggs
binds to albumin in egg whites during cooking
imaging protocol
1 min ANT/POST
immediately, 1 hr, 2 hr, 4 hr
imaging protocol for liquid emptying
30 min study at 1 min framing rate
imaging to be done immediately after ingestion of 300 ml H2O + RP
FOV for gastric emptying
distal esophagus and proximal duodenum
(stomach at top of FOV)
camera position and geometric mean calculations
ANT/POST
geometric mean calculation required
camera position and geometric mean calculations
LAO
no geometric mean calculation required
false positive or false negative
patient consumed a hamburger 1 hr ago
false pos
false positive or false negative
last solid meal consumed was 28 hrs ago
false pos
false positive or false negative
patient is on TPN
false pos
false positive or false negative
chronic cholecystitis
false pos
false positive or false negative
acalculous cholecystitis
false neg
false positive or false negative
hepatocellular dysfunction
false pos
false positive or false negative
“nubbin” sign
false neg
false positive or false negative
partial cystic duct obstruction
false pos
formula to calculate % empty
% emptying at time (t) = [(corrected ct IMMED - corrected ct at t)/corrected ct IMMED] * 100
normal emptying rate at 2H
> 40% emptying
normal retention rate at 2H
<60% retention
normal retention rate at 4H
<10% retention
normal emptying rate at 4H
> 90%
half time emptying for liquid emptying
<25 min
symptoms of Gastroparesis
- post prandial nausea - early satiety
- reflux
- abdominal pain
- vomiting
- bloating
symptoms of rapid gastric emptying
- post prandial abdominal cramps
- diarrhea
- palpitations
- diaphoresis and weakness
treatment for altered gastric emptying rates
- gastrectomy
- surgical implant to stimulate vagus nerve
- drug therapy (pro kinetics)
causes of abnormal delays
- peptic ulceration
- surgery
- diabetic gastroparesis
- scleroderma
- amyloidosis
- smooth muscle disorders
- mechanical obstruction
diabetic gastroparesis (delayed GE)
partial paralysis of the stomach due to damage to vagus nerve as it is linked to diabetic neuropathy
treatment for delayed GE
- medication
- diet management
- feeding tube (jejunostomy)
what is the process of gastric emptying?
~3 ml of liquid chyme escaping through the pyloric sphincter
where are markers placed?
iliac crest (+ uah has it on sternal notch)
fundus sits more ____.
antrum sits more ____.
fundus - posterior
antrum - anterior
formula to calculate geometric mean @ Tt
geometric mean @ Tt = sqrt(anterior ct x posterior ct)
why are counts seen rising over time in the ANT image?
food moving from the fundus to antrum over time
what %s at 0.5H and 1H indicates
“dumping”?
> 30% at 0.5H
70% at 1H
what are normal study results?
when 2H and 4H % emptying values are met
OR
2H and 4H % retention values are met
2H emptying %
> 40% emptied
4H emptying %
> 90% emptied
2H retention %
<60% retained
4H retention %
<10% retained
why is there a lag phase?
time taken for food to grind into small particles
