NM Flashcards
PET –> how does it work?
1) radiotracer –> emit positron –> travel small distance in tissue
2) meet electron –> positron & electron annihilate
3) create two 511 keV photons –> travel 180 deg apart
PET –> what radiotracer?
Fluorine-18 fluorodeoxyglucose (F-18 FDG)
PET –> F-18 FDG –> MOA?
glucose analog –> GLUT1 & 3 -> transport into cells –> phosphorylated by hexokinase –> trapped in cell
F-18 –> half life?
110 min
standardized uptake value (SUV) –> proportional to what formula?
(ROI activity x body wt) / administered activity
PET: FDG uptake –> depend on what lab values?
serum glucose & insulin levels
PET: inc insulin –> what happen to FDG uptake?
inc uptake by muscle –> dec sensitivity for mild FGD-avid lesions
PET: how long NPO?
at least 4hr –> insulin at basal level
PET: blood glucose level should be?
<200 –> prefer
PET: inject F-18 FDG –> rest in quiet room –> how long?
1hr
PET –> effect of metformin?
- inc colonic uptake
- small inc small bowel uptake
PET: salivary gland, tonsil, thyroid –> normal uptake?
symm –> mild-mod uptake
PET: bowel –> normal uptake?
diffuse –> mild-mod uptake
PET: heart –> normal uptake?
variable
PET: muscle –> normal uptake?
- usu low
- if elevated insulin –> inc uptake
- if recent exercise –> inc uptake
PET: brown fat –> normal uptake? exacerbating factor?
mild-mod
cold
brown fat –> MC location?
- supraclavicular
- intercostal
PET/CT –> evaluate what type of lung cancer? why?
only non-small cell lung cancer
small cell –> considered metastatic at dx
LN staging –> gold standard?
mediastinoscopy
PET –> malig LN –> sens? spec?
- very sens
- not spec
pulm nodule –> smallest size that can be eval by PET?
8 mm
solitary pulm nodule –> not FDG avid –> next step?
short term f/u
solitary pulm nodule –> FDG avid –> next step?
- bx
- resect
colon CA –> role of PET?
- local colon cancer –> limited role
- good for mets eval
colon CA –> initial tx –> when can do f/u PET? why?
2mo
peritx period –> inc FDG uptake –> flare phenomenon
head/neck CA –> tx –> when can do f/u PET? why?
4mo
chemorad –> alter anatomy, inflamm –> dec specificity for recurrent dz
inc thyroglobulin –> whole body radioiodine scan –> neg –> next step?
PET –> look for thyroid CA:
- undiff
- medullary
PET –> lymphoma –> inc marrow uptake –> diffuse –> ddx? (3)
- granulocyte colony-stimulating factor (G-CSF)
- ctx –> rebound effect
- malig marrow infiltration
esophagus CA –> role of PET?
ID mets –> not surg candidate
esophagus CA –> initial neoadjuvant tx –> dec FDG avid by how much –> favorable prognosis?
at least 30%
esophagus CA –> initial neoadjuvant tx –> unchanged FDG avid –> indicates what in terms of tx?
ctx ineffective –> stop ctx
cancers w limited role for PET? (4)
- HCC
- RCC
- bladder CA
- prostate
HCC –> limited role for PET –> why?
high phosphatase –> dephosphorylate FDG –> FDG diffuse out of cells
bladder CA –> limited role for PET –> why?
surrounding high urine FDG uptake
LV perfusion imaging –> evaluates what?
blood flow to myocardium
LV perfusion imaging –> perfusion abnormality –> factors to eval? (5)
- ir/reversible?
- size?
- severity: mild (subendocardial), mod, severe (transmural)?
- coronary A territory?
- assoc abnormalities? –> RV uptake, ischemia dilation, wall motion abnormal?
LV perfusion imaging –> stress –> 3 methods?
- physical –> treadmill
- pharmacologic-adrenergic –> dobutamine
- pharmacologic-vasodilatory –> dipyridamole, adenosine
myocardial perfusion imaging –> indications? (6)
- eval acute chest pain
- eval hemodynamic significance of coronary stenosis
- risk stratification after MI
- preoperative risk assessmt for noncardiac surg
- eval viability prior to revasc therapy
- eval myocardial revasc s/p CABG
risk stratification after MI –> myocardial perfusion imaging –> “high risk” findings? (5)
- sig peri-infarct ischemia
- defect in diff vascular territory –> mult-vessel dz
- sig lung uptake –> LV dysfx
- LV aneurysm
- low EF <40%
what is “hibernating” myocardium?
myocardium:
- hypoperfused
- viable
myocardial viability imaging –> 2 methods?
- # 1 F-18 FDG PET
- thallium-201 perfusion imaging
myocardium –> region of perfusion defect –> FDG uptake –> dx? tx?
viable myocardium –> CABG or percutaneous intervention
myocardium –> region of perfusion defect –> no FDG uptake –> dx?
non-viable scar –> medical therapy only
radionuclides used in nuclear cardiology? (5)
- thallium-201
- technetium-99m sestamibi (cardiolite)
- rubidium-82
- nitrogen-13 ammonia
- F-18 FDG
thallium-201:
- half life?
- decay?
- charact Xray?
- MOA?
- 73hr
- electron capture
- 69-81 keV
- potassium analog –> ATP-dep Na-K transmembrane pump –> into cell –> uptake directly proportional to myocardial perfusion
thallium-201 –> myocardial perfusion imaging –> max exercise –> perfusion defect –> at least what % stenosis?
50%
thallium-201 –> undergoes redistribution –> T/F?
T
technetium-99m sestamibi (cardiolite) –> undergoes redistribution –> T/F?
F
technetium-99m sestamibi (cardiolite) –> MOA?
passive diffusion –> into cell –> bind to mitochondrial membrane proteins –> uptake proportional to myocardial perfusion
rubidium-82:
- half life?
- decay?
- MOA?
- perfusion vs viability?
- 76 sec
- positron
- potassium analog
- perfusion
rubidium-82 –> type of stress –> exercise vs pharmacologic –> why?
pharm only –> very short half life
nitrogen-13 ammonia:
- half life?
- decay?
- perfusion vs viability?
- 10min
- positron
- perfusion
myocardial imaging –> nitrogen-13 ammonia –> pro (2) vs con (2)?
pro:
- don’t travel far in tissue –> high resolution
- short half-life –> can give lrg dose
con:
- short half life –> must be produced by cyclotron on-site
- pharm stress only
F-18 FDG:
- half life?
- decay?
- perfusion vs viability?
- 110 min
- positron
- viability only –> must correlate w sestamibi perfusion study
myocardial perfusion study:
- NPO how long? why?
- should stop what meds? why?
NPO 6hr –> dec splanchnic blood flow –> reduce liver/bowel uptake
hold CCB/BB –> allow to reach target HR
myocardial perfusion study –> stress –> max heart rate? target heart rate?
max HR = 220 bpm - age
target HR = 85% of max HR
myocardial perfusion study –> dipyridamole –> MOA?
adenosine deaminase inh –> adenosine accumulate –> vasodilate –> coronary blood flow inc 3-5x
myocardial perfusion study –> dipyridamole –> what subst must be held for 24hr prior to study? (2) why?
- theophylline
- caffeine
reverse effects of dipyridamole
myocardial perfusion study –> dipyridamole –> antidote?
aminophylline
myocardial perfusion study –> differentiate: dipyridamole vs adenosine (3)
adenosine:
- same effect as dipyridamole
- faster effect
- very short half life –> no reversal agent required
myocardial perfusion study –> regadenoson –> MOA? pro compared to adenosine?
adenosine receptor agonist –> vasodilate
easier to administer than adenosine
myocardial perfusion study –> dobutamine –> MOA?
B1 agonist –> inc myocardial O2 demand
myocardial perfusion study –> dobutamine –> indication?
adenosine contraindicated:
- severe asthma
- COPD
- recent caffeine
Tc-99m sestamibi perfusion study –> when image after injection (min)? why?
30min after inject –> allow liver activity to clear
Tc-99m sestamibi perfusion study –> gated SPECT show wall motion at time of what? perfusion imaging shows perfusion at time of what?
gated SPECT –> wall motion at time of imaging
perfusion imaging –> perfusion at time of inject
cardiac imaging –> Tc-99m sestamibi perfusion study vs PET perfusion –> which has grter sens, spec, accuracy?
PET perfusion
myocardial imaging –> significant RV uptake –> ddx? (2)
- R heart dz
- pHTN
myocardial imaging –> pulm uptake –> ddx? (1)
LV dysfx
myocardial imaging –> stress –> LV dilate –> ddx? (1)
transient ischemic dilation (TID) –> 3-vessel dz (even if no focal defect)
myocardial imaging –> what is a small perfusion defect? med? large?
- small: 1-2 segmts
- med: 3-4
- lrg: >5
myocardial imaging –> fixed perfusion defect –> ddx? (2)
- myocardial scar
- hibernating myocardium
LV –> vertical vs horizontal long axis –> U-shape point in which direction?
- vertical: U to the left
- horizontal: U point down
I-131:
- half life?
- decay?
- how produced?
- 8day
- beta particles & gamma photon (364 keV)
- generator
I-131 –> use?
therapy only:
- thyroid cancer s/p thyroidectomy
- hyperthyroid (Graves, multinodular goiter)
I-123:
- half life?
- decay?
- how produced?
- mode of administration?
- 13hr
- electron capture & gamma photon (159 keV)
- cyclotron
- PO
I-123 –> use?
thyroid imaging
thyroid –> radiotracers? (3)
- I-131
- I-123
- Tc-99m pertechnetate
Tc-99m pertechnetate:
- half life?
- decay?
- mode of administration?
- 6hr
- gamma photon (140 keV)
- IV
thyroid radiotracers –> ok during pregnancy? why?
no –> cross placenta –> taken up by fetus
when can resume breastfeeding?
- I-131
- I-123
- Tc-99m
- I-131: never
- I-123: 2-3 days after administration
- Tc-99m: 12-24hr
I-131/I-123 therapy/imaging –> patient pre-procedure prep? why?
non-suppressed TSH (high TSH level):
- stop exogenous thyroid hormone for 4wk
- 2 IM injection of TSH
inc thyroid uptake of radiotracer
ectopic thyroid tissue –> 3 types?
- lingual thyroid
- retrosternal thyroid (substernal goiter)
- ovarian teratoma (struma ovarii)
ectopic thyroid tissue –> imaging options? (2)
- I-123
- Tc-99m
thyroid nodule –> cytology indeterminate –> next step?
nuclear imaging
thyroid nodule –> hyperfxing –> ddx? (1)
benign adenoma
thyroid nodule –> cold –> ddx? (2)
- 70-75% benign colloid cyst
- 20% malig
thyroid nodule –> warm –> ddx? (1)
cold nodule –> overlapping thyroid tissue
thyroid nodule –> warm –> next step?
oblique view –> still indeterminate –> bx
what is discordant thyroid nodule? next step?
- Tc-99m –> hot –> can uptake technetium
- I-123 –> cold –> can’t trap iodine
may be malig –> bx
thyroid imaging –> normal 6hr uptake? 24hr?
- 6hr –> 6-18%
- 24hr –> 10-30%
Graves dz –> thyroid imaging –> dec/normal/inc?
- 6hr uptake
- 24hr
- 6hr –> elevated
- 24hr –> elevated
thyroid imaging –> how can differentiate if I-123 vs Tc-99m?
Tc-99m –> salivary uptake
Graves dz –> how can differentiate if I-123 vs Tc-99m?
often not possible –> thyroid uptake too strong –> salivary glands often not seen
Graves dz –> definitive tx? MC?
- # 1 I-131
- surg
MC inflamm dz of thyroid?
Hashimoto thyroiditis
Hashimoto thyroiditis -> thyroid scan –> appearance?
- diffuse inc activity (like Graves)
- patchy uptake (like MNG)
subacute thyroiditis –> thyroid imaging –> dec/normal/inc?
- 6hr uptake
- 24hr
- 6hr –> dec
- 24hr –> slight inc
thyroid cancer –> thyroidectomy –> 1-2mo later –> I-131 tx –> goal?
image + trt:
- residual dz
- potential mets
I-131 –> low dose (<30 mCi) vs high dose (100-200) –> indication?
low risk pt –> low dose:
- <1.5 cm
- no invasion of thyroid capsule
risk high –> high dose
thyroid cancer –> s/p I-131 ablation –> monitor?
follow thyroglobulin levels
thyroid cancer –> s/p I-131 ablation –> inc thyroglobulin –> next step?
I-123 scan –> assess for dz recurrence/mets
thyroid cancer –> s/p I-131 ablation –> inc thyroglobulin –> I-123 scan positive –> next step?
repeat I-131 ablation
thyroid cancer –> s/p I-131 ablation –> CI to monitor with thyroglobulin levels?
presence of anti-thyroglobulin Ab
Graves dz –> I-131 tx –> CI? (3)
- preg
- lactation
- unable to comply w radiation safety guidelines
I-131 tx –> Graves dz vs multinodular goiter –> # of tx?
- Graves –> single dose
- MNG: mult tx may be required
parathyroid imaging –> radiotracer?
Tc-99 sestamibi
nuclear imaging –> parathyroid –> indication?
localize suspected parathyroid adenoma
nuclear imaging –> parathyroid adenoma –> findings?
- early phase: inc uptake
- delayed phase: persistent retained activity
nuclear imaging –> thyroid adenoma –> findings?
- early phase: inc uptake
- delayed phase: washout
Tc-99m sulfur colloid –> uptake by what tissues?
reticuloendothelial cells:
- # 1 liver –> Kupffer cells
- # 2 spleen
- # 3 BM
Tc-99m sulfur colloid:
- Tc-99m physical half life?
- sulfur colloid biologic half life?
- Tc-99m: 6hr
- sulfur colloid: 2-3min
sulfur colloid scan –> what is photopenic defect? MCC?
complete absence of radiotracer
hepatic cyst
sulfur colloid scan –> focal dec uptake –> ddx? (3)
most hep mass:
- HCC
- adenoma
- abscess
sulfur colloid scan –> focal inc uptake –> ddx? (3)
- focal nodular hyperplasia
- liver cirrhosis –> regenerating nodule
- Budd-Chiari (hep V thrombosis) –> late stage –> inc uptake in caudate lobe
sulfur colloid scan –> what is colloid shift? ddx? (1)
spleen & BM –> inc sulfur colloid
liver dysfx –> #1 cirrhosis
sulfur colloid scan –> diffuse pulm uptake –> ddx? (4)
nonspecific:
- cirrhosis
- COPD w infx
- Langerhans cell histiocytosis
- high aluminum (antacids, excess Al in colloid preparation)
sulfur colloid scan –> focal nodular hyperplasia (FNH) –> appearance? (3)
- normal liver (contain Kupffer cells)
- inc uptake (Kupffer cells + hypervasc)
- photopenic defect (insuff colloid concentration)
focal nodular hyperplasia (FNH) –> nuclear imaging options? (2)
- sulfur colloid scan
- HIDA
focal nodular hyperplasia (FNH) –> HIDA finding?
contain bile ductules –> positive on HIDA
intra-pancreatic spleen –> nuclear imaging options? (2)
- sulfur colloid scan
- Tc-99m damaged red cell study
GI bleed –> nuclear imaging options? (2)
- Tc-99m labeled RBCs
- Tc-99m sulfur colloid
GI bleed –> Tc-99m sulfur colloid study –> cons? (2)
- sig prep time
- vasc half-life 2-3min –> rapid blood clearance
GI bleed –> Tc-99m labeled RBCs study –> in vitro vs in vivo –> which is more commonly used? why?
1 in vitro –> 95% labeling efficiency
in vivo –> worse labeling eff –> free pertechnetate –> noisier images
GI bleed –> tagged RBC study vs IR angiography –> can detect bleeding rate of?
- tagged RBC: 0.2 ml/min
- IR angio: 1 ml/min
GI bleed –> tagged RBC study –> appearance?
activity –> over time –> peristalsis of intraluminal blood –> change shape & position
Tc-99m pertechnetate –> localize to what tissue?
gastric mucosa
Meckel diverticulum –> radiotracer?
Tc-99m pertechnetate
Meckel diverticulum –> Tc-99m pertechnetate study –> finding?
- RLQ –> focal inc activity
- lat view –> activity is ant, not post
RLQ pain –> suspect Meckel diverticulum –> Tc-99m pertechnetate study –> diffuse regional inc uptake –> ddx? (2)
hyperemia:
- appendicitis
- intussusception
Meckel diverticulum –> embryology?
omphalomesenteric duct remnant
HIDA scan –> radiotracer?
Tc-99m iminodiacetic acid (IDA)
HIDA scan –> disofenin vs mebrofenin:
- max bili level?
- % hep uptake?
disofenin:
- bili 20 mg/dL
- 90% hep uptake
mebrofenin:
- 30
- 98%
HIDA scan: NPO how long?
- must have eaten within 24hr
- NPO 6hr
HIDA scan: NPO for >24hr –> next step?
cholecystokinin –> empty GB –> wait 2hr –> HIDA scan
HIDA scan –> gallbladder visualized –> dx?
no acute cholecystitis
HIDA scan –> 1hr –> gallbladder NOT visualized –> next step? why?
morphine –> contract sphincter of Oddi –> redirect bile into cystic duct
HIDA scan –> 1hr –> gallbladder NOT visualized –> can’t give morphine in what situation? why?
tracer –> nonvisualized in small bowel
theoretical risk of worsening potential CBD obstruction
HIDA scan –> 1hr –> gallbladder NOT visualized –> morphine –> when image again?
30min
HIDA scan –> 1hr –> gallbladder NOT visualized –> morphine allergy –> next step?
image for total 4hr
HIDA scan –> tracer in small bowel –> indicates?
patent CBD
HIDA scan –> 1hr –> gallbladder NOT visualized –> morphine –> 30 min –> gallbladder NOT visualized –> next step?
finished
86-98% sens for acute cholecystitis
6% –> false positive HIDA (GB non-visualized WITHOUT acute cholecystits) –> ddx (7)
- recent meal or prolong fasting
- admin CCK immed prior to exam –> persistent sphincter of Oddi relaxation
- total parental nutrition
- pancreatitis –> biliary stasis
- severe illness
- chronic cholecystitis
- cholangioCA of cystic duct
HIDA scan: what is rim sign?
inc hep activity surrounding GB fossa:
- hyperemia
- gangrenous cholecystitis
very rare –> false negative HIDA (GB non-visualized WITHOUT acute cholecystits) –> ddx (3)
- acalculous cholecystitis w patent cystic duct
- duodenal diverticulum –> simulate GB
- biliary cyst –> simulate GB
what is chronic cholecystitis?
GB –> longstanding inflamm:
- loss of GB fx
- inc risk of stone formation
chronic cholecystitis –> HIDA MC finding?
normal
HIDA scan –> finding suggestive of chronic cholecystitis?
low GB ejection fraction <35%
biliary leak –> nuclear imaging option? (1)
HIDA scan
biliary leak –> HIDA scan –> what can do to inc detection?
do study in R lat decubitus position –> promote dep pooling of bile
severe hepatic dysfx –> HIDA scan –> findings? (2)
- very poor hep uptake
- delayed blood pool clearance
hepatic mass –> HIDA scan –> finding?
focal photopenic defect
V/Q scan –> radiotracers? (3)
- Tc-99m-MAA –> perfusion
- Xenon-133 –> vent
- Tc-99m DTPA –> vent
V/Q scan –> Tc-99m-MAA –> who should get half dose? (4)
- child
- preg
- mild pHTN
- R-L shunt
V/Q scan –> Tc-99m-MAA –> relative CI? (1) why?
severe pHTN
obstruct pulm capillaries –> clinical worsening
V/Q scan –> Tc-99m-MAA –> what is clumping of MAA?
MAA –> inadvertently drawn back into syringe –> coagulation w pt blood
V/Q scan –> Tc-99m-MAA –> renal uptake –> ddx? (2) how differentiate?
free pertechnetate:
- thyroid uptake
- no brain uptake
R-L shunt:
- no neck uptake
- brain uptake
Xenon-133:
- physical half life?
- biological half life?
- decay?
- critical organ?
- physical half life: 5.3day
- biological half life: very short
- decay: gamma photon & beta emitter
- critical organ: trachea
preg –> PE –> CTA PE vs V/Q scan –> fetal rad dose?
CTA: similar to slightly higher than VQ
PIOPED II –> high probability for PE?
> 2 large (>75% segmt) mismatched segmental defect –> no assoc XR abnormality
PIOPED II –> intermediate probability for PE? next step?
1 lrg segmtal mismatched perfusion defect
not clinically helpful –> further imaging required
VQ scan –> lower lung –> what is triple match? dx?
perfusion defect –> vent defect –> matching abnormality on CXR ==> intermediate probability
PIOPED II –> low probability for PE? (3)
- 1 mod-lrg MATCHED defect
- > 3 small segmental lesions
- entire lung –> no perfusion
PIOPED II –> very low probability for PE? (3)
- nonsegmtal lesion
- stripe sign
- mid-upper lung –> 1 triple match defect
VQ scan –> what is stripe sign?
perfusion defect –> thin line of MAA uptake bw defect & pleura –> intervening perfused lung
VQ scan –> possible impressions? (5)
- normal
- very low prob
- low prob
- interm
- high
bone scan –> radiotracer?
Tc-99m MDP
bone scan –> diffuse soft tissue uptake –> ddx? (1)
renal fail
bone scan –> 3 phases?
- angiogram (flow): eval blood flow
- blood pool: eval extracellular distribution
- delayed (skeletal)
cancer pt –> bone scan –> 1 rib –> focal uptake –> low/high probability of mets?
low (10%)
cancer pt –> bone scan –> 2 adj rib –> uptake in similar location–> low/high probability of mets? ddx? (1)
low
trauma
cancer pt –> bone scan –> mult adj photopenic lesions –> low/high probability of mets? ddx? (3)
low
- infarction
- avascular necrosis
- sequela of rad tx
breast cancer pt –> bone scan –> 1 sternal lesion –> low/high probability of mets?
high
cancer pt –> bone scan –> multifocal lesions in nonadj ribs –> low/high probability of mets?
high
cancer pt –> bone scan –> 1 photopenic lesion –> low/high probability of mets?
high
bone scan –> inc uptake in brain –> ddx? (1)
recent infarct
bone scan –> inc uptake in heart –> ddx? (1)
recent infarct
soft tissue mets –> positive on bone scan –> ddx? (4)
Ca-containing:
- osteosarcoma
- neuroblastoma
mucin-producing:
- GI
- ovarian
inflamm dz –> bone scan –> uptake in soft tissues & muscles –> ddx? (3)
- myositis ossificans
- dermatomyositis
- rhabdomyolysis
bone scan –> what is superscan?
diffuse inc osseous uptake
bone scan –> superscan –> ddx? (4)
- # 1 metastatic prostate Ca
- breast Ca
- lymphoma
- hyperPTH
positive bone scan –> which bone tumors? (3)
- osteosarcoma
- Ewing sarcoma
- osteoid osteoma
bone scan –> double density sign –> ddx? (3)
- osteoid osetoma
- Brodie abscess
- stress fx
fx –> bone scan appearance:
- acute (up to 3-4wk)
- subacute (up to 2-3mo)
- chronic
- acute: 1day after injury –> uptake surrounding fx
- subacute: more focal uptake
- chronic: gradual dec uptake
what is medial tibial stress synd (shin splint)?
exercise-induced stress injury that occurs at the medial tibial mid-to-distal shaft
medial tibial stress synd (shin splint) –> bone scan appearance?
- blood flow phase: normal
- blood pool phase: normal
- delayed: tibia –> postmed –> linear inc uptake
osteoporosis –> sacrum –> insuff fx –> bone scan finding?
“Honda” sign –> sacrum –> H shaped uptake
bone scan –> indications? (9)
- bony mets
- bone tumor
- fx
- jt prosthesis –> loose or infx
- osteomyelitis
- hypertrophic pulm osteoarthropathy
- AVN
- Paget
- complex regional pain synd (reflex sympathetic dystrophy)
cemented jt prosthesis –> bone scan –> normal appearance?
up to 1yr –> activity around prosthesis
non-cemented jt prosthesis –> bone scan –> normal appearance?
up to 2yr –> activity around prosthesis
hip prosthesis –> bone scan –> finding suggestive of loosening?
focal activity at lesser trochanter
hip prosthesis –> bone scan –> finding suggestive of osteomyelitis?
generalized inc activity
hip prosthesis –> bone scan –> grter trochanter/intertrochanteric region –> mild-mod activity –> ddx? (1)
heterotopic ossification
normal XR –> bone scan –> positive on all 3 phases –> dx?
osteomyelitis
methods to inc specificity for osteomyelitis? (2)
- WBC imaging + Tc-99m sulfur colloid BM scan
- gallium-67 scan
WBC imaging –> radiotracer? (2)
- Indium-111 - WBC
- Tc-99m - WBC
WBC imaging + Tc-99m sulfur colloid BM scan –> indication? (1)
underlying abnormality –> ie fx, prosthesis –> eval for osteomyelitis
osteomyelitis –> WBC imaging + Tc-99m sulfur colloid BM scan –> appearance?
focal WBC activity –> no colloid activity
osteomyelitis –> gallium-67 scan –> appearance?
area of concern:
- bone scan –> inc activity
- gallium scan –> high inc activity
cellulitis –> bone scan findings?
- blood flow phase: inc activity
- soft tissue phase: inc activity
- delayed skeletal phase: normal
septic arthritis –> bone scan findings?
jt –> both sides –> positive –> all 3 phases
bone scan –> delayed skeletal phase –> inc activity in 2 adj vertebral bodies –> ddx? (1)
discitis
what is hypertrophic pulm osteoarthropathy?
pulm dz (ie lung CA) –> long bone –> diaphysis –> periosteal rxn
hypertrophic pulm osteoarthropathy –> bone scan finding?
long bone –> cortex –> parallel line –> inc activity
avascular necrosis –> bone scan –> finding? (2)
- initial phase –> dec activity
- hyperemic phase –> inc activity
avascular necrosis –> bone scan –> SPECT finding? (1)
- rim of inc activity
- central photopenia
spontaneous osteonecrosis of knee (SONK) –> bone scan finding?
med femoral condyle –> intense inc activity
Paget dz –> lytic phase –> XR appearance? bone scan?
- XR: normal
- bone scan: positive
Paget dz –> mixed phase –> XR appearance? bone scan?
- XR: positive
- bone scan: positive
Paget dz –> sclerotic phase –> XR appearance? bone scan?
- XR: positive
- bone scan: activity subside
Paget dz –> bone scan –> persistent cold lesion –> ddx? (1)
malig degeneration –> central necrosis
complex regional pain synd (reflex sympathetic dystrophy) –> MCC? ssx?
minor trauma –> persistent pain/tender/swell
complex regional pain synd (reflex sympathetic dystrophy) –> bone scan –> appearance?
- blood pool: variable –> usu inc
- soft tissue phase: variable –> usu inc
- skeletal: hand/foot –> mult small jts –> juxta-articular –> diffuse inc activity
kidney –> radiotracers? (3)
- Tc-99m DTPA
- Tc-99m MAG3
- Tc-99m DMSA
kidney –> Tc-99m DTPA –> what eval?
- eval renal perfusion
- measure GFR
kidney –> Tc-99m MAG3 –> what eval?
- eval renal perfusion
- estimate renal plasma flow
kidney –> Tc-99m DMSA –> what eval?
renal scarring assoc w pyelonephritis
kidney –> Tc-99m DTPA –> excreted by?
glomerular filtration
kidney –> Tc-99m MAG3 –> excreted by?
tubules
kidney –> Tc-99m MAG3 –> better than Tc-99m DMSA –> for which conditions? (2) why?
- renal insuff
- obstruction
higher extraction fraction –> better images for renal insuff/obstruction
nuclear renogram –> flow phase –> slow upslope –> suggests?
dec perfusion
nuclear renogram –> cortical fx phase –> delayed uptake –> suggests?
dec renal fx
nuclear renogram –> clearance phase –> slow/lack of clearance –> suggests?
hydronephrosis
renal A stenosis –> nuclear imaging options? (2)
- Tc-99m MAG3
- Tc-99m DTPA
Tc-99m MAG3/DTPA study –> what med is administered for eval renal A stenosis?
ACE-inh
renal A stenosis –> Tc-99m MAG3/DTPA study –> appearance?
after ACE-inh –> renogram –> abnormal or more abnormal
renal A stenosis –> Tc-99m MAG3 –> findings:
- % uptake at 2-3min
- difference in cortical activity
- time to peak activity
compared to pre-ACE inh):
- <40% uptake
- 20% difference in cortical activity
- > 2min delay in time to peak
diuretic renogram –> general procedure?
Tc-99m MAG3 –> 20min after –> administer lasix
diuretic renogram –> goal?
hydronephrosis –> cause:
- obstruction
- non-obstructive cause
diuretic renogram –> clearance half time:
- normal?
- borderline
- obstruction
- <10min –> normal
- 10-20min –> borderline
- > 20min –> obstruction
diuretic renogram –> false positive? (3)
- dehydration
- distended bladder
- renal fail (dec response to diuretic)
Tc-99m DMSA –> normal –> dx?
no acute pyelonephritis
pyelonephritis –> Tc-99m DMSA –> appearance? (3)
- focal cortical defect
- multifocal cortical defect
- diffuse dec activity
pediatric vesicoureteral reflux –> radionuclide cystography vs voiding cystourethrogram:
- sens
- rad exp
radionuclide cystography:
- no sens
- less rad exp
radionuclide cystography –> radiotracers? (3)
- Tc-99m pertechnetate
- Tc-99m DTPA
- Tc-99m sulfur colloid
radionuclide cystography –> general procedure?
radiotracer –> retrograde inject into bladder
I-123 MIBG –> use? (2)
- adult –> image pheochromocytoma
- ped –> image neuroblastoma
MIBG –> uptake by what conditions? (5)
- pheochromocytoma
- neuroblastoma
- carcinoid
- medullary thryoid CA
- paraganglioma
I-131 MIBG –> use? (1)
ped –> tx neuroblastoma
I-123 MIBG –> normal distribution?
sympathetic innervation:
- salivary glands
- heart
- thyroid
- liver
- kidney
- bladder
I-123 MIBG –> how dec thyroid uptake?
Lugol’s soln
Indium-111 pentetreotide (Octreoscan) –> indication? (2)
image:
- carcinoid
- islet cell tumor –> gastrinoma
Indium-111:
- half life?
- decay?
- production?
- 67hr
- electron capture
- cyclotron
Indium-111 pentetreotide (Octreoscan) –> uptake MOA?
octreotide analog –> somatostatin receptor:
- carcinoid
- islet cell tumor
- amine precursor uptake and decarboxylation (APUD) tumor
- head/neck –> glomus tumor (extra-adrenal pheochromocytoma)
Indium-111 pentetreotide (Octreoscan) –> normal distribution?
- kidney –> intense uptake
- spleen –> intense uptake
- liver –> less uptake
Gallium-67:
- half life?
- decay?
- production?
- 78hr
- electron capture
- cyclotron
Gallium-67 –> uptake MOA?
bind to transferrin:
- infx
- inflamm
- neoplasm
Gallium-67 –> normal distribution?
- bowel, colon –> high activity
- liver –> less
- skull
- BM
- salivary glands
Gallium-67 –> 24hr –> kidney –> activity –> dx?
renal dz
Gallium-67 –> lungs –> diffuse uptake –> dx?
infx/inflamm
Gallium-67 –> what is panda sign?
inflamm –> inc uptake:
- nasopharynx
- parotid gland
- lacrimal gland
Gallium-67 –> panda sign –> ddx? (4)
- classically –> sarcoidosis
- Sjogren
- lymphoma after irrad
- AIDS
sarcoidosis –> Gallium-67 study –> signs? (2)
- panda sign
- lambda sign –> bilat hilar + R paratracheal LAD
thallium-201:
- half life?
- decay?
- production?
- 73hr
- electron capture
- cyclotron
thallium-201 –> normal distribution?
- kidney
- heart
- liver
- thyroid
- bowel
indium-111 oxine leukocytes (WBCs) –> normal distribution?
spleen > liver»_space; BM
indium-111 oxine leukocytes (WBCs) –> pro (1) vs con (3) –> compared to gallium study?
pro:
- no physiologic bowel accumulation –> can eval abd/bowel infx/inflamm
con:
- tedious labeling procedure
- higher rad dose
- less accurate for spinal osteomyeltis
gallium study –> liver –> focal uptake –> dx?
HCC
gallium + thallium study –> indication? (3)
- Kaposi sarcoma
- TB, atypical myobacteria
- lymphoma
Kaposi sarcoma –> gallium + thallium study –> findings?
KaT: Kaposi is Thallium avid
- thallium avid
- no gallium uptake
TB, atypical myobacteria –> gallium + thallium study –> findings?
TuG: Tuberculosis is Gallium avid
- gallium avid
- no thallium
lymphoma –> gallium + thallium study –> findings?
Lymphoma likes both:
- gallium avid
- thallium avid
brain –> radiotracers? (3)
- Tc-99m DTPA
- Tc-99m HMPAO
- Tc-99m ECD
brain –> Tc-99m HMPAO vs ECD –> demonstrates what?
- HMPAO: perfusion
- ECD: living cells
brain death scan –> what is hot nose sign?
inc collateral flow –> nonspecific –> abnormal cerebral perfusion –> ie. brain death
brain –> acetazolamide challenge –> indication?
eval cerebral perfusion reserve
brain –> acetazolamide challenge –> appearance?
after acetazolamide:
- normal brain –> inc perfusion
- areas that have already maxed their autoregulatory mechanisms –> relatively lower activity compared to rest of brain
seizure –> Tc-99m HMPAO/ ECD –> appearance?
- ictal imaging (inj during sz or 30 sec after end of sz) –> hypermetabolic
- inter-ictal —> hypometab
dementia –> Tc-99m HMPAO/ ECD –> appearance?
- Alzheimer dz
- Lewy body dementia
- multi-infarct dementia
- Pick dz
symm dec activity:
- Alzheimer –> post temporal + parietal lobes
- Lewy body –> + occipital calcarine cortex
- mult-infarct dementia –> mult asymm foci
- Pick dz –> frontal lobes + ant temporal lobes
brain tumor –> recurrence vs radiation necrosis –> nuclear imaging options? (2)
- thallium-201
- dual phase F-18 FDG PET
brain –> malig glioma –> thallium-201 study –> recurrence vs radiation necrosis –> appearance?
- tumor –> uptake
- granulation tissue –> no uptake
what is crossed cerebellar diaschisis?
supratentorial lesion –> ie. tumor, stroke, trauma –> disrupt corticopontine-cerebellar pathway –> contralat cerebellar hemisphere –> dec radiotracer uptake
how to recognize MIBG scan?
- no bones
- liver > spleen
- no kidney!
high uptake in spleen & kidneys –> what study?
octreotide
how to differentiate Tc-WBC scan from In-WBC scan?
- Tc-WBC: kidney & GI uptake
- In-WBC: no kidney & GI uptake
Tc-MDP –> how localize?
phosphate analog –> chemiabsorption –> bind w hydroxyapatite on bone surface
F18-FDG –> how localize?
facilitated diffusion
I-123 & I-131 –> how localize?
Na/I symporter (NIS) –> into cell –> incorporate into thyroid hormone
thallium-201 –> how localize?
potassium analog –> Na/K ATP pump
brain death study –> Tc99m HMPAO vs Tc99m ECD –> main difference?
Tc99m ECD –> more rapid clearance from blood pool
bone scan –> abnormally low bone uptake –> ddx? (2) how to differentiate?
- poor renal fx –> too much soft tissue noise
- air in vial/syringe –> poor labeling –> free Tc –> stomach uptake
bone scan –> what is flare phenomenon?
bone mets –> ctx –> 2wk-3mo post –> look like inc size & number of lesions –> “pseudo-progression”
bone scan –> liver uptake –> ddx? (4)
- Al3+ contaminiation
- cancer –> ie hepatoma, mets
- amyloidosis
- necrosis
bone scan –> spleen uptake –> ddx? (1)
sickle cell –> auto-infarcted spleen
elderly –> fx –> bone scan –> should be positive at what time point?
1wk
bone scan –> tramline sign –> dx? next step?
hypertrophic osteoarthropathy –> CXR or CT chest –> look for lung cancer
lytic bone mets –> imaging modality of choice?
skeletal survey
blastic/sclerotic bone mets –> imaging modality of choice?
bone scan
bone scan –> single lesion –> equivocal –> next step?
XR
bone scan –> equivocal single lesion –> normal XR –> next step?
susp for bone met –> MRI
vertebral osteomyelitis –> study of choice?
- WBC scan + Gallium-67
- MRI
infx –> when would use Tc-HMPAO WBC over In-WBC? (2)
- peds: Tc99 –> lower absorbed dose, shorter imaging time
- small parts ie hands/feet
In-WBC –> critical organ?
spleen
Tc99m MAA –> particle size?
10-100 micrometer
Tc99m MAA –> when use fewer particles? (5)
- peds
- only 1 lung
- RtoL shunt
- pHTN
- preg
gallium –> critical organ?
colon
gallium scan –> panda sign –> ddx? (3)
- sarcoid
- sjogren
- treated lymphoma
differentiate: trapping vs organification?
- trapping: iodine tracer transported into thyroid gland
- organification: iodine incorporated into tyrosyl moiety
thyroid scan –> when would use Tc-99m over I-123/I-131?
recent thyroid blocker ie iodinated contrast
Tc-99m thyroid scan –> when can resume breastfeed?
24hr
I-123 thyroid scan –> when can resume breastfeed?
2-3 day
Hashimoto thyroiditis –> potential comp?
1ary thyroid lymphoma
I-131 radioiodine therapy –> dose for…
- thyroid only
- thyroid + nodes
- distant mets
- thyroid only: 100
- thyroid + nodes: 150
- distant mets: 200
I-131 radioiodine therapy –> pt should be admitted to hospital when how much residual activity?
33 mCi
hyperthyroid –> I-131 radioiodine therapy –> dose for…
- Graves
- MNG
- Graves: 15 mCi
- MNG: 30 mCi
parathyroid scan –> radiopharmaceutical?
Tc sestamibi
brain –> shunt scan –> radiopharmaceutical?
Tc-DTPA
brain –> sz scan –> finding?
- ictal: hot focus
- interictal: cold
Kaposi sarcoma –> uptake on…
- gallium
- thallium
- gallium –> neg
- thallium –> pos
HIDA scan –> CCK –> dose?
0.02 microgram/kg over 60min
HIDA scan –> morphine –> dose?
0.02-0.04 mg/kg over 60min
infant –> HIDA scan –> phenobarbitol –> dose?
5mg/kg for 5 days
sulfur colloid liver scan –> cold or hot?
- hepatic adenoma
- FNH
- cavernous hemangioma
- HCC
- cholangioCA
- mets
- abscess
- focal fat
- FNH –> hot
- rest are cold
sulfur colloid scan –> diffuse lung uptake –> ddx? (1)
Al contaminiation
sulfur colloid scan –> kidney uptake –> ddx? (2)
- CHF
- renal tx –> rejection
hemangioma scan –> radiopharmaceutical? findings?
Tc-RBC
- flow phase: no uptake
- pool: no uptake
- delayed: hot
which radiotracers are made by generator? (2)
- Tc99
- rubidium
hepatic adenoma
- sulfur colloid
- HIDA
- gallium
- sulfur colloid: photopenic
- HIDA: hot
- gallium: neg
thyroid scan –> meds that interfere w thyroid uptake?
- thyroid blockers
- IV contrast
- amiodarone
- nitrates