Gastro Classic NM Flashcards
After I131 therapy
10% decline in stimulated saliva flow
Functioning salivary gland tumor
Warthin tumor (history of smoking)
Oncocytoma
Oxyphilic adenoma
Primary salivary tumor
Increased perfusion
Decreased uptake
Multi swallow approach
6 liquid bolus
Regular peristaltic waves at swallow intervals 10-15 sec
Condensed image
Quantitative indices of esophageal transit scan
Oral transit time - <1 sec normal, <5% residual activity
Pharyngeal TT - <1.2 sec, <5%
Esophageal TT - <10 sec, <20%
Esophageal emptying rate =
(Emax - E10s)/Emax * 100 >80% normal
Nutcracker esophagus
Chest pain, dysphagia, peristaltic waves in distal esophagus
Achalasia
Degeneration of neurons in the wall of esophagus
Relaxation - - LES pressure rise
Impaired clearance and delayed transit times
Most sensitive esophageal transit scan
Diffuse esophageal spasm
Simultaneous contractions induced by liquid swallows
100% sensitivity
10% Manometry
Scleroderma
Fibrosis and vascular obliteration of muscle
Retention in lower esophagus
Clearance after upright or glass of water
Neurogenic dysphagia
Stroke
Brain tumor
Brain injury
Paralysis
Neurodegenerative disease
Gastric emptying scan preparation
Fast 4 hours
Stop prokinetics, opiates, antispasmodic, atropine, nifedipine, progesterone, octreotide, benzodiazepine for 2 days
Diabetes - - glucose <270 mg/dL
No smoke
Gastric emptying tracer
Tc-Sulfur colloid 0.5-1 mCi mix with 2 liquid eggs white - - cook in microwave
+ 2 slices of white bread, 30g jam, 120 ml water
Eat within 10 min
Contra - - food allergy and hypoglycemia
Anterior and posterior for 1 min - - geometric mean
Gastrointestinal bleeding scan = GIBS
Bleeding flow
Monitor GIT up to 24h
Detect bleeding at low flow rate 0.04mL/min
No preparation
Gastrointestinal bleeding scan radiopharmaceutical
Tc-labeled RBC - intravascular half-life allows continuing imaging over many hours
Tc-Sulfur colloid
RBC label
Tc bind
In vitro - recommended - least pert free - - 15-30 mCi in adult, 1.51*weight of child
Modified in vivo
In vivo
Tc bind beta chain of Hemoglobin
Poor RBC labeling caused by
Heparin
Iodine contrast
Doxorubicin
Lidocaine
Dd rectal from bladder activity
Lateral views
Meckel diverticulum
80-100 cm of ileocaecal valve
2 cm length
57% contain Ectopic gastric mucosa
50% at age of 2 years
Gross rectal bleeding +- abd symptoms
Meckel scan
When no active bleeding (unlike RBC)
Tc-pert 10 mCi adult, min 20 MBq child
Pretreatment with cimetidine, pentagastrin, glucagon (prevent release of pert from gastric mucosa)
Potassium perchlorate block secretion from gastric mucosa - - false negative
False - positive - genitourinary uptake - - SPECT
>1 cm diameter - - 90% accuracy
Hepatobiliary scan preparation
Fast 2-6h, children 2-4h, infant 2h with clear liquids possible (not milk)
Fast >24h–false positive , gallbladder don’t fill - - treat with sincalide
Stop opioids 4 half lives or give naloxone
No fast - - false positive, no gallbladder within 1h
Most common indication - - acute cholecystitis
Hepatobiliary scan
Tracer, mechanism
Tc-labeled HIDA bind to albumin - - extracted by hepatocyte similar to bile salts, free fatty acids, bilirubin - - secreted in biliary canaliculi without conjugation
2/3 enter gallbladder via cystic duct
1/3 into duodenum via CBD and sphincter Oddi
Dynamic 60 min - - activity in biliary ducts 10-30 min, in bowel by 60 min
HIDA
Tc-Disofenin - even when bilirubin >25 mg/dL
Tc-mebrofenin - higher liver extraction 98% vs 89%, more rapid biliary clearance 17 min vs 19 min - - preferred if moderate-severe hepatic dysfunction, in neonates with hyperbilirubinemia min 1 mCi
Adult 3-5 mCi - - more if high bilirubin
Child 0.05 mCi/kg, min 0.5 mCi
Acute cholecystitis
Non visualized gallbladder - - acute or chronic cholecystitis
Acute acalculous cholecystitis sensitivity 70-80% vs calculous 95%
Gallbladder not seen after 60 min - - morphine sulfate 0.04 mg/kg IV over 2-3 min only when tracer in small bowel (or second injection of Tc) - - continue for 30-60 min
False negative - 25% acalculous have no cystic duct obstruction, only inflammation of gallbladder wall
Contra morphine
Abs - increased intracranial pressure in children, respiratory depression
Rel - acute pancreatitis
Non visualized gallbladder
Fast >24h or recently ate - - false positive
CBD obstruction or severe cholestasis
Cholecystectomy
Acute calculus cholecystitis
Chronic cholecystitis
Images at 4h
GBEF procedure
Gallbladder not filled by 60 min - - acute or chronic cholecystitis
Gallbladder filled - - gamma camera 35-40° LAO
Sincalide 0.02 microg/kg into 30-50 mL syringe dilute with saline - - infusion pump for 60 min
Dynamic imaging starts simultaneously frame/min
GBEF = (max-min)/max*100
GBEF <38% = abnormal
Sphincter of Oddi dysfunction
Pain after Cholecystectomy
Delay in bile flow into duodenum (>10 min)
Delayed entry of tracer into bowel (>30-60 min)
Failure of sincalide
Morphine immediately after HIDA injection - - sensitivity >80%
Biliary atresia
Neonatal jaundice
Early diagnosis within 60 days
Kasai procedure - hepato porto enterostomy
Unresponsive - - liver transplant
DD neonatal hepatitis
Phenobarbital to increase bile flow and specificity
Persistent hepatogram and no biliary-to bowel transit over 24h
Postmorphine gallbladder visualized
No acute cholecystitis
Yes chronic cholecystitis
Phenobarbital
Biliary atresia
Morphine
After HIDA to speed the study for suspected acute cholecystitis
Spasm of sphincter Oddi - - raise CBD pressure - - facilitate gallbladder filling
Only when tracer in liver, CBD and small bowel
Sincalide
Synthetic cholecystokinin
Longer delay in bowel because of accumulation in empty gallbladder
Severely prolonged - - biliary obstruction (stone)
Indication: Biliary dyskinesia, fast >24h, Sphincter Oddi dysfunction, Calculate GBEF, TPN
Action: contraction of gallbladder and relaxation of sphincter Oddi
Contra - - allergy, pregnancy
Visualized gallbladder
No acute cholecystitis
Tracer in small bowel within 60 min
No CBD obstruction
Persistent in blood pool >20 min
Reduced hepatocellular function
Normal - - clear from blood pool within 5 min
Salivary gland scan preparation and protocol
Fast
Stop smoking
No thyroid blocking agents 48h
Tc pert - - dynamic frame/sec 1-2 min - - sialagogue - - frame/2-3 min for 20 min
Salivary gland scan interpretation
Acute Sialoadenitis - - hyperemia and edema - - increased uptake and retention
Chronic Sialoadenitis - - variable uptake - - little or no uptake in late stage
Sialolithiasis - - 80-90% Submandibular - - poor or absent excretion, dilated ducts possible
Early dry mouth - - affects excretion phase
Mass lesion - - increased perfusion, decreased uptake - - кроме Warthin tumor, Oncocytoma, Oxyphilic adenoma
Esophageal transit indication
Dysphagia after surgery
Mechanical obstruction
After radiotherapy
Manometry not possible
Response to treatment
Esophageal transit preparation and protocol
Fast 3h or overnight
Test - swallow water 10 ml
Stand, face 80° oblique to the left
Low energy high resolution parallel hole collimator
FOV - from mouth to epigastric area
Keep in mouth 10 ml 1 mCi Tc-colloid - - swallow 2 sec after start dynamic - - frame/0.125 sec 1 min, 64*64, zoom 1 - - static 60 sec
After 30 min repeat with semisolid bolus jellied drink 10 ml 1 mCi - - static 60 sec
Single swallow
Poor sensitivity
Low specificity
Assess reflux
Dynamic 120 sec
4-5 Valsalva maneuver - - increased intra abdominal pressure
Gastric emptying lag phase
Frequent acquisition every 15 min in first hour
GIBS indication
Mid or lower gastrointestinal bleeding
When upper gastrointestinal bleeding is excluded by nasogastric lavage
Anemia and sometimes melena
Gastrointestinal bleeding classification and causes
Upper - - above ampulla of Vater
Mid - - from ampulla of Vater to terminal ileum - - angiodysplasia, Crohn, diverticul, Meckel
Lower - - colonoscopy - - angiodysplasia, diverticulosis, neoplasm, adenomatous polyp, IBD, infection
GIBS protocol and interpretation
Dynamic - - frame/1-5 sec for 1-2 min - - vascular mass
Frame/min for 60-90 min
No bleeding - - delayed image 2-6h or 18-24h - - better accuracy
Bleeding - - area of extravascular activity increase over time or focus of activity that move - - SPECT
Meckel protocol
1 image every 30-60 sec for 30 min
Static
SPECT
No bowel and no gallbladder
Stone in CBD
Biliary dyskinesia
Biliary pain
No stones
Gallbladder dysmotility - - stasis - - chronic inflammation
Check GBEF
Benefit from Cholecystectomy
Normal
No bowel
Stone in CBD
No gallbladder
Duodeno-gastric reflux
Dyskinesia of Sphincter Oddi
Gallbladder and choledochus fully distended
No stones
No duodenum
Postmorphine gallbladder visualized
Delayed visualisation of gallbladder - - chronic cholecystitis
