Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
62 Cards in this Set
- Front
- Back
|
agent for liver spleen scan
size of particles |
Tc99m-SC
0.3-1um |
|
|
size of Tc99m-SC used in lympho
|
<0.22um
|
|
|
how is SC taken up
|
by kupffer cells (phagocytes of reticuloendothelial system)
|
|
|
what is seen on a nml liver spleen scan
|
liver > spleen
nmlly should see very little bone marrow activity |
|
|
how is the manner of imaging different if you are doing a SC scan to look at bone marrow
|
dose is much higher if you are looking at BM
liver and spleen are shielded as well |
|
|
typical dose for liver-spleen scan
|
4-6mCi Tc99m-SC
|
|
|
nml length of liver
|
17-18cm
|
|
|
smallest lesion on SC scan that can be routinely imaged
|
8mm
|
|
|
what is colloid shift
|
incresaed concentration of Tc99m-SC by spleen and BM
|
|
|
causes of colloid shifft
|
hepatic dysfxn
and/or portal HTN |
|
|
mechanism of colloid shift
|
portal HTN --> shunting SC to spleen and BM
decreased fxn of kupffer cells (either or both mechanisms may be involved) |
|
|
ddx for diffuse lung uptake on liver-spleen scan
|
cirrhosis,
infx , DIC, trauma |
|
|
finding that can be assoc with SVC or innom vein obx
|
volus cna travel via collaterals into recanalized umbilical vein --> focal hot spot in quadrate lobe
|
|
|
what does xenon retention in liver during VQ scan indicate
|
fatty infiltrate
|
|
|
etiology for persistent activity in blood pool on liver-spleen scan
|
cirrhosis or etoh liver disease
|
|
|
ddx for enlarged liver with decreaeed SC activity in liver
|
nml variant
hepatitis mets DM |
|
|
what is often seen in mets to liver on SC scan
|
multiple focal defects
|
|
|
appearance of FNH on SC scan
|
usually indistinguishable from nml liver (b/c they contain kufpper cells)
rarely, they are photopenic |
|
|
appearance of hepatic adenoma on SC scan
|
appears as a defect
|
|
|
what is budd chiari syndrome
|
hepatic vein thrombosis
|
|
|
what happens to liver in budd chiari syndrome
appearance in liver spleen scan |
caudate lobe enlarges
liver can have mottled appearance |
|
|
appearance of hemangioma on SC scan
|
defect on SC scan
|
|
|
appearance of hemangioma on tagged RBC scan
|
increased activity on blood pool images
|
|
|
how to estimate spleen size in a kid
|
5.7 + (0.31xyrs)
|
|
|
ddx focal lesion in spleen
|
cyst
hematoma abscess infarct neoplasm |
|
|
if defect in spleen is wedge shaped, think ....
|
infarct
|
|
|
malignancy that has associated mets to spleen
|
lymphoma
melanoma chorioepithelioma sarcoma |
|
|
ddx n/v spleen
|
splenectomy
congenital asplenia autosplenectomy |
|
|
methods to do GIB scan
which method is preferred |
Tc99m-RBC**
Tc99m-SC |
|
|
what is the bleeding rate that can be detected on tagged RBC scan
|
0.2mL min or faster
|
|
|
what is bleeding rate that can be detected on angio
|
1mL/min
|
|
|
if activity on a bleeding scan stays in same spot, think...
|
vascular abn (aneurysm, angiodysplasia)
|
|
|
radiopharmaceutical for meckel's scan
|
Tc99m-pertechnetate
|
|
|
what can pt be pre-treated with for meckel's scan
|
cimetidine (blocks release of pertechnetate from ectopic gastric mucosa)
pentagastrin (in enhances mucosal uptake of pertech) glucagon (slows gut motility) |
|
|
things that can cause false + on meckel's scan
|
ureter activity
other ectopic gastric mucosa hyperemic inflammatory lesions AVM hemang aneurysm neoplasm intussusception |
|
|
how long should blood pool activity last in HB scans
|
no more than 5-10 mins
|
|
|
what if blood pool activity on HB scan is incresed
|
think hepatic dysfxn
|
|
|
how is disida dealt with in the liver
|
radiopharmaceutical is rapidly removed from circulation by active transport into hepatocytess, then secreted into bile canaliculi
|
|
|
what is the nml t1/2 for hepatic clearance on HIDA scan
|
15-20 min
|
|
|
what fraction of HIDa is nmly excreted directly into SB
|
2/3
1/3 enters GB |
|
|
dx of acute cholecystitis on HB scan
|
if n/v GB by 4hrs, then acute chole
|
|
|
appearance of rim sign
|
curvilinear band of activity along R inferior hepatic edge, above GB fossa
40% of these pts may have per or gangrenous cholecystitis |
|
|
mechanism of rim sign
|
radiopharm gets delivered peripherally to bile canaliculi, but then gets trapped there by edema
|
|
|
appearance of cystic duct sign
|
visualization of small nubbin of cystic duct, a/w acute chole
|
|
|
uses of CCK in HIDA scan
|
to empty GB in pt fasting >24h prior to exam
EF to evaluate spincter of Oddi dyskinesia Differentiate fxnal from anatomic duct obx |
|
|
uses of morphine in HB scan
|
used to shorten imaging time when GB is n/v at 1 h and there is still enough activity in liver
|
|
|
when should morphine not be given
|
when there is a cystic duct sign
|
|
|
when is phenobarbital given for HB scan
|
to prime hepatic enzymes to increased IDA excretion...
helps to distinguish btwn biliary atresia and neonatal hepatitis |
|
|
what should neonates be primed with before HB scan
|
phenobarb x5 days
|
|
|
downside of giving CCK
|
may cause a false neg for chronic chole by speeding up time it takes to visualize GB who may have otherwise been delayed
can prolong biliary to bowel transit time |
|
|
guidelines for giving morphine
|
can give when biliary tree and bowel are seen by 1h, but n/v GB
DO NOT USE IF THERE IS A CYSTIC DUCT SIGN! |
|
|
NM findings of chronic cholecystitis
|
delayed vis of GB
delayed biliary to bowel transit also suggestive |
|
|
nml GB EF
|
>50%
|
|
|
decreased GB EF
|
<35%
|
|
|
what does the liver scan sign suggest
|
mechanical or fxnal CBD obx
|
|
|
what is the "liver scan sign"
|
on HB scan, only visualize the liver
|
|
|
ddx for delayed vis of GB
|
chronic chole
vs partial cystic duct obx in setting of acute chole |
|
|
examples of mechanical obx of CBD
|
calculus
neoplasm |
|
|
ex of fxnal obx
|
ascending cholangitis
hepatitis meds |
|
|
what woudl you see in a parital CBD obx
|
persistent vis of CBD or delayed clearance from CBD
|
|
|
what is the "reappearing liver sign"
|
increased activity in liver after liver has emptied
seen in bile leak |
|
|
nml solid food t1/2 emptying time
liquids |
90 min
40 min |
