Nukes Flashcards
1
Q
knee jerk for ocreotide scan
A
hot spleen & kidneys
2
Q
I-123 vs I-131
A
- 1-123 lower E (159 keV)–> higher dose –> 24 hr imaging. 1/2 life 13 hrs. no b-emisison. Cardiac & adr act MC.
- I-131 high E (~364)–> crummier images. 1/2 life 8d. b-emission
3
Q
Tc WBC vs In WBC
A
- both spleen > liver
- Tc-renal & GI. In does NOT. Higher count –> cleaner
- WBC- lung (<24 hrs)–> GI.
4
Q
Tracer localization via chemisorption
A
- Tc-99 Medronate (MDP)
- binds HYDROXYAPATITE
5
Q
Tracer localization via facilitated diffusion
A
F-18 FDG
6
Q
Tracer localization via passive diffusion
A
T-99 sestamibi, tetrofosmin, HMPAO, ECD.
7
Q
Tracer localization via secretion
A
-T-99 IDA, pertechniate
8
Q
I-123, 131, T99 pertechnetate- mech of transport
A
I-analog transported via Na/I symported NIS.
9
Q
K analogues
A
Thallium, Rb (transplant via Na/K ATP pump)
10
Q
T-99 sestamibi-how is it transported
A
lipophilic cation with affinity to negatively charged mitochondria
11
Q
ECD vs HMPAO
A
ECD faster clearance from blood pool
12
Q
preparation bone scan
A
15-25mCi tracer
img at 2-4 hr (let ST clear)
13
Q
MDP uptake dep on…
A
1) OB act (1˚at cortex)
2) blood flow
3) vitD
14
Q
normal MDP uptake/localization
A
- bone
- kid, bladder
- breasts,
- ST
15
Q
ways of getting free Tc
A
1) no enough Sn
2) air (oxide)
3) H2O–> clumping
16
Q
Where is free Tc
A
- stomach
- thyroid
- salivary glad
17
Q
making a good bone scan in setting of poor renal function
A
1) oral hydration 2-6 hrs before
2) 4th phase (24 hr delay)-problem=T99 half life is 6hrs
18
Q
when does “flare phenomenon” occur. Why. How you know it’s flare?
A
2wk-3 mo
- bone healing
- xray: more sclerotis, start improving at 3 mo
19
Q
persistent visualization skull sutures on bone scan
A
renal osteodystrophy
20
Q
focal breast uptake on bone scan
A
-cancer
21
Q
renal cortex hotter than adj lumbar spine on bone scan
A
hemochromatosis
22
Q
diffuse renal uptake on bone scan
A
crx, urinary obstr
23
Q
Liver uptake on bone scan
A
1) Al3+ contamination
2) hepatoma, mets
3) amyloidosis
4) liver necrosis
24
Q
spleen uptake on bone scan
A
-autoinfarcted spleen
+ scattered hot & cold areas from mult bone infarcts
25
lung uptake on bone scan
* hetrotopic Ca (dystrophic or mets)-classically OS
- fibrothorax
- 1˚ lung tumor
- radiation change
- sarcoid, berrylliosis
- wegener's
- alveolar microlithiasis
26
muscle uptake on bone scan
rhabomyolysis
27
diffusely decreased skel uptake on bone scan
1) Free Tc
| 2) bisphos
28
arterial intravasation on bone scan
arterial--> distal
29
causes insufficiency sacral fractures
- OP
| - radiation
30
when should bone scan be performed to evaluate for fracture in elderly?
1 wk
31
AVN dx tests
MRi--> bone scan (if CI or need to image mult bones at once)
32
Donut sign-AVN femoral head
-hot on outside, cool in inside
33
AVN appearance on bone scan
dep on timing
- early=normal or cold (via interrupted bs)
- later-hot (at time that radiographs are becoming sclerotic)
34
hypertrophic osteoarthropathy affects what pt of bone
periosteum
35
donut sign-tumors
cystic (GCT, ABC, telangiectasia OS)
36
benign HOT bone lesions
- abc, gct
- oo, ob
- FD
37
use of PSA in predicting bone mets
<10 ng/ml nearly excludes
| >100 highly predictive
38
MC loc for single metastatic lesion
spine
39
Mets on a bone scan
1) rarely single (15-20%)
2) super scan
3) MULT, randomly distributed into diff sites
40
how many dying prostate cancer pts have mets?
85%
41
which nuc medicine scan is bone uptake always abN
MIBG, 1-131, ocreotide
42
where does breast bone met usually go
spine
43
what pt of skeleton does lung cancer met to?
appendicular
44
which scan is most sup at detecting NB bone met?
MIBI
45
what pt of bone does NB met to?
metaphysis
46
what pt of skeleton does osteopokilosis spare?
spine & skull
47
next step: equivocal lesion on bone scan
plain film- no corresponding lesion=more concerning --> MRI
48
radiation change on bone scan
- acute (2-3 mo)-warm
| - late (~6 mo)-cold. Persistent.
49
trickery re: bone scan and no kidneys
horseshoe
50
ways of showing FD on bone scan
- hot mandible
| - leg that looks like pagets
51
superscan causes
1) diffuse mets-breast & prostate
| 2) metabolic-hyperPTH, renal osteodystrophy, Pagets, thyrotoxicosis
52
cold lesions on bone scan
1) late radiation change
2) early AVN
3) infarct (very early or late)
4) anaplastic/lytic tumor (renal, thyroid, NB, myeloma)
5) artifact-prosthesis, PM, etc
6) hemangioma-vairable
7) bone cyst (w/o fx)
8) mature HO
53
utility of bone scan re: heterotypic ossification
- serial exams to detect if process is active-resect once mature (cold)
- *still active=higher rate recurrence
54
F18-NA PET vs T99-MDP
F18-Na-cleaner, shorter exam time, more expensive. critical orgn=bladder
-MDP: bone (critical) & kidney, fuzzy
55
F18-NA vs FDG PET
will look similar in pts w/ GCSF or EPO (diffuse bmarrow) but brain uptake on FDG
56
when would you use Tc99 HMPAO instead of In-WBC for infection? Why not use it all the time?
Uses:
1) kids (lower absorbed dose & shorter imaging)
2) small pts-T99 does better in hands, feet
Not all the time:
1) .T99 shorter half life
2) GI and gb act obscures act in those areas
57
In-WBC-which cells are labeled?
90% NP (lymphocytes tend to be killed by radiation)
58
In-WBC critical orgn
spleen
59
what happens if In-labeled cells fragment?
indium binds transferrin-see liver and bmarrow uptake
60
How is MAA prepared?
denaturation of human serum albumin
| -give via IV
61
MAA biologic half life
4 hrs
62
xenon 133 vs Tc99DTPA: gas vs aerosol
x=gas
| DTPA=aerosol
63
Xenon 133: KeV, half life and bio halflife, critical orgn
- 81 KeV
- 5.2 d
- 30 s
- trachea
64
3 phases of xenon 133 administration
1) wash in (single max inspiration and breath hold)
2) equilibrium (breathing room air and xenon mix)
3) washout (Breathing normal air)
65
DTPA administration
- requires more pt cooperation (breath through mouth guard w/ nose clamp for several mins)
- must do this part before MAA?
66
quantification studies
- before lung resection/tx
| - must use Xe + Tc MAA bc Xe won't interfere w/ Tc
67
significance of tracer in brain during v/q scan
shunt
68
MAA particle size and #
- 10-100 micrometers
| - 500K
69
when do you reduce particle amount and why?
* risk a functional PE
- anyone with fewer capillaries (don't want to block more than 0.1% of caps, ie: children, 1 lung)- 10-50K in neonates
- R-->L shunt (don't want to block caps in brain). 100K
- pulm HTN
- pregnant
* this does not reduce dose-normal dose of Tc added to fewer particles
70
clumped MAA moa, app
blood in syringe
| multiple scattered focal hot spots
71
persistent pulmonary activity during xenon washout
air trapping (COPD)
72
accumulation Xe over RUQ
fatty liver
73
clumping Tc-99m DTPA
mouth, central airways, stomach (from swallowing)
74
what if tracer is in thyroid or stomach on VQ scan?
1) free Tc
| 2) R to L shunt
75
what do you need to call R to L shunt?
tracer in brain
76
if you suspect a R-->L shunt, how do you alter scan?
decreased particles
77
unilateral perfusion defect of whole lungg, no ventilation defect
CT or MR
| Ddx= mass (MC), fibrosing mediastinitis, central PE
78
Gallium vs Indium WBC?
- gallium can bind to NP mets after cells are dead (helpful particularly in chronic inf)
- spine-gallium
- abd/pelvis-I-WBC
79
Gallium-67: production, half life, decay, emitting gamma photopeaks, when do you scan, critical orgn, normal localization?
- cyclotron via bombardment of Zn68 --> complexed with citric acid --> gallium citrate
- HL 78 hr
- electron capture
- 93 KeV (40%), 184 (20%), 300 (17%), 393 (5%)
- colon
- liver (highest), MARROW (and cortex), spleen, salivary/lacrimal glands, breasts, GP/thymus (kids)
- kid/bladder <24 hr (faintly up to 72 hr)
- <24 hr faint lung, >24 hr faint bowel
80
when is gallium uptake + in chest?
-infection
-sarcoid-active disease, guide bx/lavage graded ag bg lung
-CHF
-atelectasis
-ARDS
-idiopathic pulmonary fibrosis-monitor resp to rx
-immsupp: PCP, bacterial PNA. (-) for kaposi and ?lymphoma
-early drug run-bleomycin, amdiodarone)
-
81
lambda sign
1-2-3 (bilateral hila, R paratracheal LN)
82
panda sign
NP, parotid, lacrimal
| *sarcoid, sjogrens, treated lymphoma
83
FDG-PET pleural talc
+ via granulomatous rxn
84
doses MAA, Xe and DTPA
- 3-5 mi
- 10-20
- 30
85
segmental defect size
- small <25%
- moderate 25-75%
- large: >75%
86
high probability PE (97%, PPV 88%)
* mismatched segmental defects. No associated radiographic abN (excludes clinical mimics).
- 2+ L
- 2 L & 2 mod
- 4 mod
87
intermediate probability (20-85%)
- 1L mismatch
- 1-4 M
- triple match LOWER lung
88
low probability (5-19%; NPV 84%)
- 1 L or M matched
| - UPPER/MID lung triple match
89
very low probability (2-5%)
- 3- sm perfusion defects
- non segmental lesions-CMG, diaph elevation, aortic aneurism, pl eff, hila, PM artifact, fissure, bullae
- fissure/stripe sign-thin line MAA uptake btw perfusion defect and adjacent pleural surface representing intervening perfused lung
90
CTA vs VQ scan radiation doses to maternal breast and fetus
- CTA: breast 10-70mGy (ACR rec 3mGy/br). Fetal dose 0.1-0.66mGy
- VQ: breast <0.31 mGy, fetus 0.1-0.37
91
changes to routine VQ scan in the pregnant pt
-perfusion only
-adm 1/2 standard dose
~100K particles
92
what are the functions of the kidney?
80% secretion
| 20% filtration
93
Tracers used in renal scintigraphy
- DTPA- Filtration. GFR (small portion protein bound, not filtered--> slightly underestimation)
- MAG3-Secretion (ERPF)
- DMSA-binds prox tub cortex-ass cortical integrity
- GH (glucoheptonate)-structural (binds to cortex) or functional (filtered)
* critical orgn= bladder (exc dmsa-kid)
94
how is renal scintigraphy performed and phases
- pst (ant if tx or horseshoe)
| - 3 phases-blood flow (~20s), cortical, clearance
95
symmetrically decreased flow to kidneys
technical error (poor bolus)
96
asymmetrically decreased flow to kidneys
- renal a/v thrombosis
- acute rejection
- acute pyelo
- chronic high grade obstruction
97
asymmetrically increased renal flow
renal artery aneurysm
98
kidney pathology in which flow is normal
- vasomotor nephropathy- imm after sx, should recover 1st 2 weeks
- ATN-~wks-mo's
- interstitial nephritis
- cyclosporin tox
99
how is cortical function/phase of renal scan assessed?
- 1 min (really drinking up that contrast)
- steep slope :)
- draw area of interest and background area of interest-correct for background. Can be screwed up if obtained over liver or spleen
100
how is clearance/excretory function/phase of renal scan assessed?
- reach half peak counts ~7-10 mins
| - quantify retention via 20/3 or 20/peak ratio
101
20/3 or 20/peak ratio
peak count at 20 mins vs peak count at 3 (Normal <0.8)
| -peak count at 20 vs peak count (N 0.3)
102
what to do in setting of suspected obstruction. how does this differ from standard renal scintigraphy scan?
lasix renogram
- wait 30 mins after clearance phase. If act still in collecting system-give lasix
- MAG3 > DTPA (better in pts w/ poor renal function)
103
lasix renogram exam interpretation-no obs, indeterminate, obstructed
- no obstruction-clears w/o lasix
- no obs-50%+ w/i 10 mins after lasix
- indeterminate: w/o 50% 10-20 mins
- obstructed-w/o >20 mins
104
MCC indeterminate lasix renogram
-dilated pelvis (reservoir effect)
105
false positive "obstruction" on lasix renogram
- poor response to lasix-bad renal function or dyhydration
- reservoir effect-v dilated renal pelvis (MC)
- back pressure-full bl, neurogenic bladder (resolve w/ foley)
106
DTPA vs MAG3 renal fx
- DTPA-GFR, ie: decreased uptake and flow (loss of perfusion pressure)
- MAG3- secretion tracer (retention)
107
2 ways of performing ACE-i renogram
1) standard dynamic study --> ace-i
| 2) 1/2 dose baseline study --> full dose
108
(+) ACE-i renogram
->10% worsening
109
ACE-i renogram study preparation
- stop ACE-i (3-5 d if captopril), CCB
- NPO 6 hr (for PE ace-i)
- maintain IV access in case of hypoTN
110
how would a suspected fluid collection app on renal scintigraphy
photopenic (exc urinoma only on DELAYED phase)
111
renal scintigraphy chronic kidney transplant rejection
-no uptake
112
renal scintigraphy vascular complication (thromb) s/p kid tx
-no flow or function
113
indications for structural renal scintigraphy
acute pyelo- (-) uptake)
- scarring/mass- (-) uptake, scarring decr volume
- coumn of bertin vs mass-mass=cold
114
testicular scintigraphy
blood flow study
- torsion vs other cause of pain
- Na99m-TcO4
- tape penis up out of way
- normal= symmetric flow
- acute torsion=nubin sgx (focal decrease)
- delayed torsion-halo of increased activity w/ central photopenis
- abscess-same as delayed
- acute epididymitis-(+)
115
trapping vs organification of iodine analogues
- "trapping"-analog transported into glad. I-123, I-131, Tc-99
- organification-oxidized by thyroid peroxidase, bound to tyrosyl moiety. Tc-99 does not do this
* only 1-5% Tc-99 taken up by thyroid==> background levels higher
116
when would you choose Tc-99 over I-analogue?
if pt had recent I blocker (ex: I contrast)
117
when can you resume breastfeeding?: Tc-99, I-123, I-131, fdg 18
- Tc-99: 12-24 hrs
- I-123: 2-3 d
- I-131: nxt pregn
- fdg 18-8 hrs
118
how much I analogue do you give for uptake test? When do you image?
- 5 microCi 131
- 10-20 microCi 123
image at 4-6 hr and 24 hr
119
normal values I uptake. How do you correct for background?
4-6 hr: 5-15%
24 hr: 10-35%
correct background prior to 24 hr (use neck counts - thigh counts)
120
factors that affect I-uptake test
1) renal function- (+) stable I pool --> (-) numbers
2) dietary I-variable and controversial
3) meds-Thyroid blockser, nitrates, IV contrast, amiodarone
121
Causes of increased I uptakes
- graves
- early Hashimoto
- rebound after abrupt withdrawal of antithyroid mx
- dietary I deficiency
122
Decreased I uptakes
- hypoth
- renal fx
- mx (Th blockers, nitrates, IV contrast, amiodarone
- deiatry iodine overload
123
which meds decrease I uptake test?
- Thyroid blockers
- nitrates
- IV contrast
- amiodarone
124
MCC hyperTh
graves 75%!
125
nukes findings Graves
-diffuse homog uptakes
*24 hr may be lower/N than 6 hr via rapid TH production
+pyramidal lobe (45%)
126
Plummer dx
Multinodular toxic goiter
| -wt loss, anxiety, niosmina, tachycardia
127
nukes findings multi nodular toxic goiter
-heterogenous, moderately elevated uptake
| -
128
toxic vs non toxic MN goiter
- toxic=hot nodules, cold background
| - non toxic= moderate/warm nodules, normal background
129
toxic MN goiter vs graves
- toxic MN goiter=medium high uptakes (<50%)
| - graves= high uptake (>50%)
130
MCC goitrous hypothyroidism in US
-hashimotos
131
nukes appearance hashimotos
inhomogeneous focal cold areas
| *acute= graves appearance
132
subacute thyroiditis (de Quervains) sequelae
-viral prodrome --> hyperTh --> decreased uptake
133
subacute thyroiditis vs graves
labs are the same: TSH (-), T3/T4 (+)
| SAT low uptake
134
solitary thyroid nodule: how often cancerous if hot vs cold
20-40% cold
| <1% warm
135
are most thyroid nodules warm/cold?
cold, ie: benign
136
discordant nodule
hot on Tc-99 but cold on I-123
Cancers can trap but lose ab to organify
need to prove it's hot on I-123 before calling benign
may be caused by 1) congenital enz deficiency that int organification OR 2) drug blockage: propylthiouracil
137
which thyroid cancer does well with radiation?
papillary (+ sx)
138
which thyroid cancer does not do well with radiation?
medullary
139
who doesn't resp well to I-131 radiation therapy
1) medullary cancer
2) prior rx- pretreatment dose 50% more
3) hx of methimazole rx (even if yrs ago)
140
ideal thyroid uptake after sx?
<5% (assume some thyroid is leftover after sx)
| *>5% =painful ablation (steroids, NSAIDs), return to OR
141
ideal TSH prior to I-131 treatment
```
ideally 50 (30 is minimum)
-want TSH super high--> residual cancer/thyroid tissue really thirsty
```
142
medullary subtype nukes
- cold on thyroid scan
- MIBG, ocreotide + (NE org)
- PET+ as aggressivenss/calcitonin+, ie: calcitonin > 1000 --> PET sensitive. Calcitonin <500, not good
143
how do you get post op TSH up?
1) stop thyroid med
| 2) recombinant TSH "Thyrogen"
144
how do you decide on post op I-131 dosing
```
depends on stage
100 for thyroid only
150 for thyroid + nodes
200 for distal
*test before letting pt go home to see if they need to go to hospital
```
145
when do pts need to be admitted after I-131 rx?
- 33 mCi residual activity
| - NRC: 7 mR/h measured 1 m from pt's chest
146
possible side effects of I-131 rx
- pulmonary fibrosis if given with lung mets
| - Sjogrens-salivary gland damage. DOSE RELATED
147
routes that body uses to eliminate I-131?
mainly urine
| -sweat, tears, saliva, breast milk
148
precautions at home s/p I-131 rx
*for 3 days
- water
- hard candy (keep radio tracer from jacking your salivary glands)
- distance from others
- bathroom hygiene (flush twice, sit down if male)
- disposable uteinsils
- wash clothes separately
149
when to get pregnant and resume breast feeding s/p I-131 rx
- 6-12 mo before getting pregnant
| - no more breast feeding this round
150
absolute CI to I-131 rx
- severe uncontrolled thyrotoxicosis
| - pregnancy
151
healthcare workers participating in I-131 rx
- thyroid check 24 hrs later
| - RSO inspect room after dc if admitted
152
uptake in liver on I-scan
post treatment scan
153
how to monitor for recurr s/p I-131 rx
thyroglobulin (anything >0!)
154
I-131 and dialysis
adm imm after dialysis to maximize time I-131 on board
- (-) dose (not excreted until next sash)
- dialysate down sewer. Tubing stay in store
155
I-131 for hyperTh- dosing
- 15 mCi for Graves (more vascular)
- 30 mCi for multi nodular (harder to treat the capsule)
-should resolve 3-4 mo
156
why don't you treat if pt is in severe thyrotoxicosis
risk thyroid storm
| -can cool them down w/ mx (bb, methimazole)
157
when do you not use methimazole?
- allergy
- neutropenia
- pregnancy (use PTU)
158
exophthalmos and I-131 rx
some say don't
159
wolff-chaikoff Effect
large ingestion/infusion I --> TH (-)
160
MCC hyperPTH
- adenoma (85%)
- HP (12%)
- cancer (3%)
161
two techniques to localize PTH lesions
1) dual phase
| 2) dual tracer
162
dual phase PTH scan
- Tc-99 sestamibi
| - 10 min (thyroid + PTH uptake) and 3 hrs img (abN PTH uptake)
163
what does sestamibi dep on?
- mitochondrial density
| - blood flow
164
false positive dual phase PTH scan
1) thyroid nodule
2) h/n cancer
3) LAD
165
dual tracer PTH scan-tracers, positive
1) Something that goes to thyroid and PTH (Tc-99 sestamibi or 201-thallium chloride)
2) only to thyroid (I-123, pertechnetate)
(+) on subtraction = PTH abn
166
problems with dual tracer technique
1) more tracers
2) motion not tolerated well by subtract img
3) things that mess w/ thyroid img
167
False positives and negatives of dual tracer technique
FP: 1) thyroid adenoma (MC) 2) thyroid cancer 3) parathyroid cancer
FN: small sized adenoma (MC), 4 gland HP.
*consider if negative study in setting of abN labs
168
MIBI (+) LN
cancer
169
breast specific gamma img (BSGI)
uses MIBI bc focal uptake is abN
170
ways of img brain in nukes
1) planar (brain death only)
2) spect
3) PET
* planar and spect use lipophilic agents proportional to bf, which should mimic metabolism
- pet proportional to metabolism
171
agent of CNS nukes
*all perfusion (mimicking met)
- HMPAO, ECD
- extracted, used for parenchymal img
- neutral and lipophilic-cross BBB. Unstable lipophilic forms cover to hydrophilic state-trapped
- GM > WM
-DTPA-not extracted/used for parenchymal img, ie: no SPECT
172
HMPAO
hexamethylpropyleneamine oxime
173
ECD
ethyl cysteine dimer
174
SPECT
single positron emission CT
175
HMPAO vs ECD
ECD:
- slower washout, better blood clearance (better brain to background ratio), preferred in stroke img
- 15-30 mins ideal img
- parietal, occipital
- no intracerebral redistribution
HMPAO:
- faster washout
- 15 min-2 hr ideal img
- FL, thal, cerebellum
* Tc-99m HMPAO preferred since it accumulates in brain parenchyma within 2 min and takes several hours before significant redistribution
176
angiographic tracer of CNS nukes
Tc-DTPA (bc stays in blood)
| -main uses: shunt, NPH, brain death
177
how soon after seizure is tracer adm?
30 s
178
tracers for seizure localization
- HMPAO, ECT
| - PET less practical
179
Thallium 201-production, decay, half life, E peaks, route of transport, high yield uses, normal uptake
- cyclotron
- electron capture
- 3 d(73 hrs)
- 69 & 81 keV
- K analog, active transport (require living cell)
-thyroid, SG, lungs, heart, skel m, liver, spleen, bowel, kidneys, bladder
uses:
- cardiac viability
- toxo- (-)
- lymphoma (+)
- kaposi (+) (gallium-)
- tumor (+)
- necrosis (-)
180
cns nuke tracers for tumors (diff from dementia or seizures)
```
201 TI (mc)
99Tc-sestamibi
```
- + in tumor > inflamm
- scalp=control
181
gallium+ cns
- CNS lymphoma
- Toxo
- bacterial abs
- cyrptococcus inf
- Tb
*kaposi= (-)
182
what to use to differentiate lymphoma from toxo?
thallium
Lymphoma (+)
Toxo (-)
183
"nose sign"
ext carotid --> maxillary branches
| *can't be used to call brain death
184
what should be checked to confirm brain death
```
kidneys (adequate uptake)
injection site (no extrav)
```
185
stroke on SPECT-acute, subacute, chronic
acute= cold
SA- warm (luxury perfusion)
chronic=cold
186
luxury perfusion
paradoxical vascular dil/blood flow in relatively avascular infarcted brain
-48-72 hrs, aka "subacute stroke"
187
utility of nukes in TIA
cerebrovascular reserve via adm acetazolaide (Diamox) (vasodil) --> perfusion tracer
- areas maxed out on auto regulatory vasodilator less intense
* may benefit from revascularization
188
nukes study for dementia
FDG PET
| *HMPAO and ECD can be used. FDG great renal clearance (good target to background images), resolution PET > SPECT)
189
normal brain on FDG PET
- symm
- BG >15% cortex
- cerebellum <15% cortex
- thal= cortex
190
FDG PET alzheimers
parietotemporal (-)
* pst cingulate gyrus first abN
- ID to PD!
191
FDG PET multi infarct dementia
scattered (-)
192
FDG PET dementia w/ Lewy bodies
- OL (-)
| - preservation mid pst cingulate gyrus ("cingulate island sign")
193
cingulate island sign
preservation of mid pst cingulate gyrus in dementia w/ lewy bodies
194
cingulate gyrus
The cingulate gyrus is the curved fold covering the corpus callosum. A component of the limbic system, it is involved in processing emotions and behavior regulation. It also helps to regulate autonomic motor function.
195
FDG-PET picks/frontotemporal dementia
FL/TL (-)
| -mimics depression!
196
FDG-PET neurodegenerative disorders
spare motor strip
197
CSF nukes img-tracer
111 In - DTPA
| *intrathecal adm
198
abN CSF nukes study
1) tracer in Vt (via reflux) (ex: NPH)
| 2) failure to clear from cisterns and localize over convexities by 24 hrs
199
normal CSF nukes study
1) 0 hr: adm
2) 2-4 hr: basal cistern
3) 4- 24 hr: Sylvian fissure, interhem cistern
4) 24 hr- over convexities, cleared from cisterns,
200
NPH CSF nukes study
early entrance and persistence in LVt
| delayed ascent to parasag region (>24 hrs)
201
NPH MRI findings
- periVt T2/FLAIR +
- aquaducteal flow void
- thinning/bowing of cc
202
NPH vs non-obstructive communicating hydroceph
NPH has normal opening P on LP
203
CSF leak sites
1) cribriform plate and ethmoid sinus
2) sella turcica into sphenoid sinus
3) ridge of spehnoid to ear
204
how to test for CSF leak in nukes
1) img basilar cisterns (1-3 hrs)
| 2) nasal pledgets- (+) if tracer in pledgets:serum > 1.5
205
shunt patency
- tracer in peritnoeum=distal end patent
| - tracer in Vt-proximal end paten (can force it in by squeezing distal limb)
206
shunt occlusion
- prox: no tracer in Vt or it's there but doesn't clear
| - distal: delayed tracer in peritoneum (>10 mins)
207
gold standard for gastric motor function
gastric emptying study
208
what pt of menstrual cycle should gastric emptying be performed?
first 10 d
209
what's more sensitive: solids or liquids
solids (but some emptying problems may be liquid only)
210
what has lag phase? solids or liquids
solids (stomach grinding up food)
| -5-20 mins
211
artifactual increased counts in gastric emptying
attenuation correction as food moved back and forth btw stomach
212
which drugs should be stopped prior to gastric emptying study and when?
*2 d before
1) prokinetics (metoclopramide (reglan), tegaserod (zelnorm), erythromycin, domperidone (motilium)
2) opiates
3) anticholinergic/antispasmodic-donnatal, bentyl, robins, levsin
4) CCB
5) antacids
serotonin rec antags (classically ondansetron/zofran) are okay!
1/2 insulin morning dose (avoid hypoglycemia, schedule early morning)
213
GI bleed scan vs angiogram sensitivity
nukes: 0.1 ml/min
| angiogram-1 ml/min
214
to what pt of Hbg is t-99 tagged?
b-chain
| *must first be reduced via stannous ion (tin, tinning)
215
ways in which T99 is tagged to RBC
1) in vivo
- tin injected
- Tc-99 pertechnetate injected
- tin bind Hb --> reduces Tc --> Tc bind Hb
* 60-80% bound --> lots of free Tc ==> dirty images
* worse if tubing heparinized or recent IV contrast given
2) in vivo-in vitro--binds 85%
- tin injection
- blood withdrawn (15-30 mins). added to Tc-99 and anticoagulant
- reinfected 10 mins later
3) in vitro (98% binding, $$$)
- blood withdrawn --> added to tin & Tc-99 kit --> reinject
216
how is GI bleeding scan obtained?
dynamic (as opp to static, transmission, spect or dual tracer)
217
GI bleed fake outs
- hydro
- tx kid
- varices/angiodysplasia
- penis
- hemangioma (over liver or spleen)
- free Tc in stomach
*THESE THINGS SHOULD NOT MOVE
218
+ GI study
1) extravasc
2) move (distal colon=exception)
3) intensity +
219
alternative ways of doing a bleeding scan
Tc sulfur colloid-fast clearance (scan w/I 30 mins), blind spots (stomach, splenic flexure, hepatic flexure)
-pros: less prep, good target to background
220
how many meckel's diverticulum will take up Tc99-pertechnitate
10-30%
221
when should you do a meckel's scan?
when they're not bleeding
222
how to make a Meckel's scan better
- pentagastrin-(+) uptake pertechnetate by gastric mucosa
- H2 blockers (cimetidine, ranitidine)-block secret of pertechnetate out of gastric cells
- glucagon-slows gastric motility
223
false positive and negative Meckel's scan
- FP: bowel irritate (recent scope, lax use)
| - FN: recent in vivo labeling of RBCs, recent barium study (attenuated)
224
what changes about tracer dosing in setting of hyperbilirubinemia
give higher doses
225
HIDA scan prep
- NPO 4 hrs
- eaten w/I 24 hr (if too full, won't let tracer in) (CCK)
- hold narcotic for 6 hr (or 3 half lives)-trigger sphincter of oddi contraction --> delays bowel visualizeion
226
time line normal hida scan
liver ~5 mins
| GB/ bowel -20-60 mins
227
time line abN hida scan
bowel but no gb w/I 4 hrs
OR
no gb at 30mins-1 hr + morphine
228
cystic duct sign
nub of activity in cystic duct ass w/ acute cholecystits
229
rim sign
gangrenous cholecystitis (20%)
230
biliary obstruction
"liver scan sgx" via back P in CBD
| -no gb, bile ducts, or bowel
231
showing chronic cholecystitis
1) delayed GB filling-not seen at 1 hr but seen at 4
| 2) EF < 30% w/ cck stim
232
Decreased EF
1) chronic cholecystiitis
| 2) acute acalculus cholecystitis
233
dosing cck and morphine
cck: 0.02 µg/kg over 30-60 mins, 15-30 min before the exam
morphine: 0.02-0.04 mg/kg over 30-60 mins, max 3mg
*should never inject these w/I 30 mins of one another
234
drug induced cholecystatic jaundice
prompt uptake, delayed excretion
- chlorpromazine, erythromycin, birth control (estrogens), anabolic steroids, statins (sometimes)
* may mimic biliary obstrcution
235
biliary atresia vs neonatal hepatitis
tracer in bowel=hepatitis
| *if you don't see it in bowel, delayed img at 24 hr
236
reappearing liver sign
-labeled dil track sup into peri-hepatic space, coat surface of liver giving appearance of paradoxically incr act in liver after initial decrease from livery emptying into bowel
237
elevated bilirubin
- >5 mg/dl
- may be suggested with increased renal activity
- suggest DISIDA or BROMIDA over HIDA (increases non-dx/inconclusive/FN exams
238
sulfur colloid liver scan
- FNH 40% hot, 30% cold, 30% neutral
- regenerating nodule
- hot quadrate lobe (SVC/innominate vein obstr)
- hot caudate lobe (Budd-Chiari)
239
liver lesion RBC +
cavernous hemangioma
- >1.5 cm
- ant, pst img; 30 mins-3 hr
- hot on delay, ø immediate flow or pool
- FN: small size (MC), partially fibrosed hemangioma, close to vascular structure, perceived increased act on flow img
240
Gallium + liver lesions
HCC
| abscess
241
Xe hot liver lesions
focal fat
242
size of particles of sulfur colloid scan
0. 1-1.0 µm
- too big-spleen eat them and stuck in lungs)
- too small-bone marrow eats them.
243
colloid shift
sulfur colloid uptake by spleen or bmarrow in setting of:
- diffuse hepatic dysfunction, portal HTN, hypersplenism, mbar activation
- most specific causes: cirrhosis, diffuse liver mets, DM, blunt spleen trauma
244
diffuse pulmonary activity in sulfur colloid scan
- excess aluminum
| - primary pulm issues (reflecting phagocytosis by pulm MPs)
245
renal act on sulfur colloid scan
- CHF mc (decreased renal bf/filtration P)
- renal tx-rejection (colloid trapped in fibrin thrombi of microvasc)
- COxB, DIC, TTP
246
hemangioma vs Angiosarcoma
angio hot on immediate flow or pool
247
focal fat
Xe+
| SC (-)
248
SUV =
(FDG concentration at time T) / (dose/body wt)
>2 generally abN
249
high bg
>150-200
250
eff of insulin
drives into m
251
when do you img fdg-pet ct following rx?
- 2-3 wks after crx
- 8-12 wk s/p radiation
* avoid stunning induced Fns and inflamm induced FPs
252
reducing brown fat
1) warm room
2) propranolol, reserpine, diazepam
3) high fat/low carb diet
253
hibernoma
focal brown fat
| -ddx=liposarcoma, so resected
254
obesity eff on SUV
higher (fat takes up less llc)
255
Ki67 proliferation index
+ = more aggressive tumor
256
where do you inj FDG in setting of breast cancer?
- opp side
| - pt supine, arms up
257
when do you use FDG-pet for breast cancer screening
if CI to MRI
258
FDG cold tumors
- BAC
- carcinoid/NE (low/intermed grade)
- 50% RCC
- perotneal bowel/liver implants-small and adj bowel
- perivesicular dx-missed by adj bladder
- mucinous anything
- prostate
- 60% HCC (variable g6p that can't trap FDG
- nonseminomatous testicular CA (or Luke warm)
- MALT lymphoma
- necrotic or cystic tumors
259
which renal tumor is FDG hot
oncocytoma
260
diffuse thyroid FDG+
hashimotos
261
seminomatous vs non-sem CA
non-sem cold/Luke warm
| -sem=hot
262
metformin eff on fdg
large > small bowel uptake
| *hold for 48 hrs
263
FDG avid bowel spots
cancer
| villous adenoma
264
FDG NETs
high grade
265
FDG pit adenomas
benign ones are hot
| -horm w/u and MRI
266
when is adrenal FDG uptake abN
> liver...variable
| -compare to non-con ct (<10hu)
267
FDG in sarcoid
cardiac
| -can use as 1˚ dx test or if bx failed
268
recurr lymphoma vs thymic rebound
recurr lymphoma=hot; round
| -thymic rebound= warm; normal thymus shape
269
lymphoma fdg
usually hot
| -MALT = low avidity
270
FDG endometrium
1) 1-4
2) ovulation (d 14)
- diffuse
- premeno
271
FDG endom: normal vs cancer
cancer= focal, post meno
272
FDG ovaries
ovulation
- ovoid rim w/ photogenic center
- premeno
273
benign FDG+ gyn lesions
-fibroids
endom cysts
-vesicovag fistula- urine spilled.
-misregistration in bladder/ureters-avoid by minimizing time btw PET and CT
274
use of FDG w/ osteosarcoma
- SUV Max (bc very heterog tumor); higher=higher grade; predictor of overall survival
- response to neoadj rx (FDG taken up by viable tumor)
- not used for screening bc so non-spec
275
Indium 111-prod, decay, peaks, half life, moa, uses, labelling process
- cyclotron
- electron capture
- 67 hr
- 173 and 247 keV
- Fe+ analog
-bind to WBC, ocreotide or DTPA (CNS img)
* must first be hooked to strong chelator.
- must isolate WBC prior to labeling (otherwise binds transferrin in blood!)
276
ocreotide scanning uses
* NE tumors:
- carcinoid
- gastrinoma
- PG
- SCLC
- medullary thyroid CA
- merkel cell tumor
- lymphoma
- meningioma
277
ocreotide scanning phases
early (4 hrs) and delayed
| -early: no bowel
278
MIBG
- noradrenalin analog--> taken up by adrenergic tissue
- pheochromo, PG, NB (bone mets)
- link w/ I-123, I-131
- block thyroid with Lugol's iodine or perchlorate
279
which meds interfere with MIBG?
- CCB
- labetalol (other bb's have no eff!)
- reserpine
- TCA
- sympathomimetics
280
brown fat nukes
- FDG-PET-
- MIBG (sympathetic innervation
* shoulders, clavicles
281
ocreotide scan in setting of suspected insulinoma
- ocreo can trigger hypoglycemia
| - give D50 bf and after or just have it ready
282
ocreotide scan prep if pt on ocreotide
stop rx for 3 d before
283
benignity vs malignancy gastronome vs insulinoma
gastronoma usually mal
| insulinoma usually benign
284
when is ocreotide better than mibg?
everything except adrenal pheo, NB
285
what is best choice for non-functional islet cell tumor
fdg-pet
| *mibg & ocreotide are both crap
286
prostascint
111-In label to Ab Capromab Pendetide (ProstaScint) --< PSA
- rising PSA + negative bone scan-looks for ST mets
- offers salvage rx (radiation to surgical bed)
- critical orgn=liver
287
various 111-In scans and critical orgn trivia
prostascint-liver
- wbc-spleen
- ocreotide-spleen
288
particle size: lymphoscintigraphy, VQ, liver spleen
<0.2 microns (<200 nm)
- 10-100 microns (10,000-100,000 nm)
- unfiltered-all sizes
289
sentinel node detection
10-50 nm Tcc99m-sulfur colloid for melanoma and breast cancer
290
sentinel node detection melanoma
- utility is in lesions 1-4mm depth
| - intradermal int in 4 spots around lesion/excison scar--> img
291
sentinel node detection breast cancer
superficial or deep into pec m
292
breast specific gamma img
- 20-30 mCi Tc99-sestamibi in Cl arm --> img 20 mins later
- (foot injection if img both breasts)
- FP: FA, FC, inflamm
- FN: deep, <1cm, medial, overlying heart
293
cardiac img tracers
- t T99-sestamibi
- t99-tetrofosmin
- thallium (older, redistributes)
294
when to img cardiac tracers
- 30-90 mins for T99
| - thallium-10 mins
295
cardiac stress test prep
- NPO 4 hrs (decreased GI bf)
- stop bb, cab, long acting nitrates for 24 hrs
- no caffeine ~12 hrs if using adenosine-related perfusion stress agents
296
chemical stressors
- regadenoson-less se's/bronchospasm than others
- dipyridamole
- adenosine-AV block
* no caffeine
-dobutamine-beta 1 agonist. avoid in LBBB. pt cannot be on bb. Better in pts w/ COPD, asthma or have taken caffeine in 12 hrs
297
LBBB classic artifact on cardiac stress tests and which drug to use
- reversible perfusion defect at septum via improper relaxation during diastolic coronary filling bc discard rhythms
- need a perfusion drug.
- Dobumatin causes more FPs (incr HR--> decr septum relaxation)
298
fixed vs reversible defects on img
| -fixed with surrounding reversible
- fixed=scar
- reversible=ischemia
- infarct w/ peri-infarct ischemia
299
LV cavity larger on stress vs rest
transient ischemic dilation
| -diffuse SE hypo perfusion-correlates with hi risk dx (L main or 3 vess)
300
fixed cavity dilation
dilated cardiomyopathy
301
RV activity on rest
RV hypertrophy
302
lots of splanchnic act on cardiac stress
-not stressed enough
303
stunned myocardium
perfusion +, contractility (-)
304
hibernating
perfusion (-), contributed (-) , FDG+, thallium redistribution
305
hibernating vs scar
hibernating takes up FDG and redistributes thallium
306
multicoated acquisition scan (MUGA)
angiogram using tagged RBCs that is gated
- calculates EF (more accurate than myocardial perfusion for LVEF)
- performed in LAO (best septal view)
- falsely low EF: LV overlapped w/ LA or RV OR LA is big
- falsely high EF-ROI over spleen (wrong subtraction)
307
rubidium 82 & NH3
PET myocardial perfusion
| 1/2 life 75 s vs ~10 mins
308
Regadenoson
adenosine rec agonist
| few se's.
309
dipyridamole
inh bd of adenosine
310
adenosine
vasodilator
| -aminophylline=antidone
311
agents for bone pain ass w/ metastatic disease from breast, prostate cancer
1) Sr 89-Cl
2) Sm-153 ETMP
3) Ra-223 dichloride
312
Absolute CIs to Sr and Sm bone pain rx
- pregnancy
- breast feeding
- renal fx
313
Strontium-Sr89 (Metastron)
- complexes with hydroxyapatite
- worst agent, highly myelotoxic
- b-emitter
314
samarium-Sm 153 (quadrate)
- complex w/ hydroxyapatite
- b-decay and 28% via gamma ray (103 kev), ie: used for img
- renal excretion
- myelotoxic
315
Sr89 vs Sm153
- SR89: 15-30% drop in platelet and WBC. 8-12 wk recovery
| - Sm-153: 40-50% drop, 6-8 wks
316
radium-Ra 223 (xofigo)
- Ca-absorbed at sites of mineralization
- emits 4 alpha particles (shorter range than Sr, Sm--> less hematog.
- long half life- 11.4 d (shipping)
- non hematog tox mc than hematoma (diarr, fatigue, n/v, bone pain)
- GI excretion
- IMPROVES SURV! (prostate mets)
317
Yttrium-90
- beta emitter
- max tissue penetration ~10 mm-spares most of adj liver parenchyma
- pretreatment lung shunt check-10-20% decrease dose, >20% radiation pneumonitis
- 20-40 µm (trapped in tumor, but doesn't block vess/bf
- dose: 100-1000 Gy delivered (need at least 70 for success)
- emission: 175 and 185 kev
- half life: 2.67 d
318
radioimmune rx + y90
-for refractory non-hodgkin lymphoma'
* preop with rituximab to block CD20 recs on circulating cells and in spleen
1) I-111 labeled Ab (ibritumomab tiuxetan/Zevalin) --< CD20 recs on Bcells==> eval tumor burden
2) Y90 rx
* if altered bio distribution, don't treat
- mc se's: TCP, NP (90%), ie: don't give to pts w/ PC < 100k
- can be discharged w/ proper care at home
319
% R --> L shunt
[(whole body count-lung count)/whole body] x 100%
320
LVEF calculation
(end diastolic count - end systolic count)/ (end diastolic counts - background counts)
321
thallium, cardiac img
- high 1st pass extraction 85%
- quick redistribution-dynamic exchange btw myocardial cytosol and vascular blood pool ie;: post stress img <10 mins post injection and delayed 24 img
322
ddx decreased pulmonary perfusion/absent perf
SAFE POEM: Swyer-James syndrome, pulmonary Agenesis/hypoplasia, mediastinal Fibrosis, pleural Effusion, Pneumonectomy, Obstruction by tumor, pulmonary Embolus, Mucous plug.
323
DTPA-uses
- Tc-DTPA-lung vent
- Tc-DTPA-kidney filtration
- Tc-DTPA-CSF
- In-DTPA- liquid emptying
324
Liver scan
- blood pool act, ø excr into bg, gb, or bowel at 60 min
- obtain 4 and 24 hr delayed img
-hepatitis
-biliary obstruction
-
325
captopril renogram FPs
dehydration
-captopril induced hypoT
CCBs
326
en block transplant
2 peds kidneys transplanted into adult
