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AJT CORE > CORE - Nucs > Flashcards

CORE - Nucs Flashcards

1
Q

Medications administered prior to Meckel’s scan

A

cimetidine/ranitidine, pentagastrin, glucagon

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2
Q

MAG3 is preferred to DTPA in…

A

moderate or severe renal failure, immature kidneys (peds), transplant kidneys

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3
Q

Syndromes associated with pheochromocytoma

A

NF1, VHL, MEN 2, Carney’s triad

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4
Q

Whole body tracer distribution: liver > spleen, bones, salivary glands

A

Ga-67

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5
Q

Whole body tracer distribution: liver = spleen, bones, no salivary glands

A

Tc-99m sulfur colloid

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6
Q

Whole body tracer distribution: spleen > liver, bones

A

In-111 WBC or Tc-99m HMPAO WBC

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7
Q

Whole body tracer distribution: salivary glands, cardiac, thyroid, parathyroid

A

Tc-99m sestamibi

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8
Q

Whole body tracer distribution: liver > spleen, no bones, salivary glands

A

I-123/I-131 MIBG; NO renal uptake (important to see pheo and neuroblastoma)

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9
Q

Whole body tracer distribution: spleen > liver, no bones, kidneys

A

In-111 pentetreotide (octreotide scan)

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10
Q

Whole body tracer distribution: liver, spleen, kidneys, cardiac, bowel

A

thallium-201

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11
Q

Whole body tracer distribution: gastric, salivary glands, thyroid

A

free pertechnetate or I-123/I-131

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12
Q

Tracers with cardiac activity

A

sestamibi, tetrofosmin, MIBG (low), thallium-201, F-18 FDG

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13
Q

Breast uptake on Ga-67 scan

A

mild uptake is normal in pregnant or lactating women

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14
Q

Thyroid uptake on MIBG scan

A

forgot to give Lugol’s (aqueous iodine)

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15
Q

Adrenal uptake on MIBG scan

A

normal adrenal uptake of MIBG is seen in some patients

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16
Q

SNR and spatial resolution with higher energy radiotracers

A

lower SNR and spatial resolution with high energy tracers (relative to low energy tracers)

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17
Q

Is I-123 or I-131 MIBG more likely to have cardiac activity?

A

I-123 MIBG

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18
Q

Causes of free pertechnetate

A

insufficient stannous ions or air in vial/syringe

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19
Q

Tc-99m HDP is used for which study?

A

bone scan

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20
Q

Difference between NaF bone scan vs. FDG PET with marrow stimulation?

A

F-18 NaF bone scan will not have brain uptake

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21
Q

Diffuse marrow uptake on FDG PET DDx

A

G-CSF, post-chemotherapy, EPO, myelodysplastic syndromes, thalassemia, CML, severe anemia, diffuse mets (less likely)

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22
Q

Focal uptake in shoulder on bone scan

A

consider arthritis (also in hip or knee)

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23
Q

Segmental focal rib uptake on bone scan

A

rib fractures

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24
Q

Prominent skull sutures on bone scan

A

renal osteodystrophy

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25
Q

Focal breast uptake on bone scan

A

breast cancer; mild diffuse uptake is normal (especially in younger women)

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26
Q

Prominent renal cortical uptake on bone scan

A

hemochromatosis

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27
Q

Diffusely increased renal uptake on bone scan (greater than spine on posterior projection)

A

chemotherapy, ATN; urinary obstruction is not a cause (Core Review)

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28
Q

Liver uptake on bone scan

A

aluminum contamination, amyloidosis, mets (or primary HCC), liver necrosis, metastatic calcification

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29
Q

Splenic uptake on bone scan

A

auto-infarcted spleen in sickle cell (patchy hot and cold areas)

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30
Q

Lung uptake on bone scan

A

osteosarcoma mets, metastatic calcification, alveolar microlithiasis, Wegener’s, berylliosis, sarcoidosis

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31
Q

How often is a solitary lesion on bone scan benign?

A

80% are benign

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32
Q

Solitary sternal focus of uptake on bone scan

A

breast cancer met

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33
Q

Increased sacral uptake on bone scan

A

insufficiency fracture (especially if H-shaped)

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34
Q

Diffusely decreased skeletal uptake on bone scan

A

free pertechnetate or bisphosphonate therapy

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35
Q

Benign vs. malignant vertebral body fractures (bone scan)

A

linear = benign; involvement of posterior elements = malignant

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36
Q

Flare phenomenon (bone scan)

A

good response mimics a bad one; increased size and number of lesions on bone scan <3 months after treatment

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37
Q

Signs of flare phenomenon

A

lesions becoming more sclerotic on plain film, lesions improve on bone scan >3 months after treatment

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38
Q

Cold mets on bone scan

A

RCC, thyroid, myeloma, +/- lymphoma

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39
Q

Spinal hemangioma on bone scan

A

cold

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40
Q

Active heterotopic ossificaton

A

hot on bone scan (mature is cold); increased risk of recurrence if resected

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41
Q

Long bone periosteal uptake on bone scan + NEXT STEP

A

hypertrophic osteoarthropathy; next step is CXR or chest CT

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42
Q

Paget’s in spine on bone scan

A

involves both vertebral body and posterior elements (classically), may also expand vertebral body

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43
Q

Bone scan uptake for AVN

A

cold (early) => hot => cold (late)

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44
Q

3-phase hot on bone scan DDx

A

osteomyelitis, osteoid osteoma, reflex sympathetic dystrophy, fracture, septic arthritis, neuropathic joint, active Paget’s

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45
Q

Increased mandible uptake on bone scan

A

fibrous dysplasia (young), Paget’s (old)

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46
Q

Benign lesions hot on bone scan

A

fibrous dysplasia, GCT, ABC, osteoblastoma, osteoid osteoma

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47
Q

Benign lesions cold on bone scan

A

simple bone cyst (without fracture)

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48
Q

Causes of metabolic superscan

A

hyperparathyroidism, renal osteodystrophy, osteomalacia, myelofibrosis, Paget’s; HOT skull on metabolic superscan

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49
Q

Equivocal lesion on bone scan - NEXT STEP

A

plain film (if that’s also equivocal, get an MRI)

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50
Q

Periarticular uptake on delayed phase of bone scan

A

reflex sympathetic dystrophy

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51
Q

Septic arthritis on bone scan

A

3-phase hot on both sides of joint

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52
Q

Shin splints vs. stress fracture (bone scan)

A

shin splints hot on delayed phase only, while stress fracture is 3-phase hot

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53
Q

Indication for sulfur colloid + WBC study

A

evaluate for osteomyelitis near prosthesis or fracture (photopenic on sulfur colloid)

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54
Q

Why is sulfur colloid + WBC no good for spine?

A

In-111 WBC gives false positives in spine (use Ga-67 instead)

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55
Q

Diffuse peri-prosthetic uptake on bone scan DDx

A

normal for cemented arthroplasty <1 year and cementless arthroplasty <2 year; also may be infection or less likely loosening

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56
Q

Prosthetic loosening on bone scan (hip)

A

focal uptake along stem and lesser trochanter (infection would be diffuse); both are excluded by a negative bone scan

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57
Q

When to use Tc-99m HMPAO WBC?

A

peds (lower absorbed dose and shorter half-life), imaging hands/feet

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58
Q

Indications for V/Q scan

A

contrast allergy or low GFR with concern for PE

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59
Q

Probability of PE with a normal perfusion study

A

none; normal perfusion study excludes PE

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60
Q

Xe-133 vs. Tc-99m DTPA differences

A

Xe only has anterior and posterior projections and has wash-in, equilibrium, and wash out phases; Tc-99m DTPA allows for multiple projections, but has only a single phase, may also see clumping in airways

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61
Q

Brain or renal uptake on MAA scan

A

right-to-left shunt

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62
Q

Particle size for MAA

A

10-100 micrometers

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63
Q

Indications to half MAA dose

A

peds, right-to-left shunt, pulmonary HTN, pregnant; ~100,000 particles (normal is 200k to 500k)

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64
Q

Focal “hot spots” in lungs on MAA scan

A

blood was drawn back into the syringe => clumping

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65
Q

Persistent pulmonary activity on washout phase of Xe-133 study

A

COPD

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66
Q

Hepatic uptake on Xe-133 study

A

hepatic steatosis if diffuse, focal fat if focal

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67
Q

Lung shunt fraction study

A

performed with Tc-99m MAA; <10% is normal, 10-20% needs a decreased Y-90 dose, >20% is at risk for radiation pneumonitis

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68
Q

Entire single lung is photopenic on MAA scan + NEXT STEP

A

mass, fibrosing mediastinitis, or central PE; need to get CT or MRI of chest

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69
Q

Ga-67 uptake in lungs

A

sarcoidosis, PCP, IPF, lymphangitic carcinomatosis, military TB, fungal infection

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70
Q

Ga-67/Tl-201 uptake - Kaposi sarcoma

A

Ga-67 cold, Tl-201 hot

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71
Q

Radiotracer to use for suspected abdominal infection

A

In-111 WBC (no bowel uptake)

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72
Q

Meningioma is hot on…

A

Tc-99m MDP and In-111 pentetreotide

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73
Q

Malignant otitis externa findings

A

hot on Ga-67 and bone scan

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74
Q

Radiotracer that “traps but does not organify” (thyroid imaging)

A

Tc-99m pertechnetate (slowly washes out of thyroid); I-123/I-131 are organified

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75
Q

Radiotracers used for thyroid uptake quantification

A

I-123 or I-131 (NOT Tc-99m pertechnetate)

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76
Q

Hot caudate sign

A

Budd-Chiari; increase caudate uptake on sulfur colloid scan

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77
Q

High probability on V/Q scan

A

2+ large mismatched segmental defects (without assoc. radiographic abnormality); “large” = >75% of segment; may involve contiguous segments (confluent appearance)

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78
Q

Very low probability on V/Q scan (4)

A

solitary triple-matched defect in mid-to-upper lung, non-segmental lesion, stripe sign, 1-3 small segmental defects

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79
Q

Indications for Tc-99m pertechnetate for thyroid scan (over I-123/I-131)

A

recent thyroid blocker, recent iodinated contrast; Tc-99m pertechnetate slowly washes out of thyroid

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80
Q

Normal RAIU (radioactive iodine uptake) values

A

5-15% at 4 hours, 10-30% at 24 hours; only with I-123 or I-131; thigh used for background correction

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81
Q

Medications causing decreased RAIU (radioactive iodine uptake)

A

thyroid blockers (PTU/MZ), nitrates, amiodarone, iodinated contrast

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82
Q

Increased RAIU (radioactive iodine uptake) DDx

A

Graves, multinodular goiter, early Hashimoto’s, dietary iodine deficiency, rebound (after cessation of PTU/MZ), lithium

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83
Q

Decreased RAIU (radioactive iodine uptake) DDx

A

late Hashimoto’s, subacute thyroiditis, renal failure, iodine load (Wolff-Chaikoff effect), thyroid hormone replacement, ectopic thyroid hormone, PTU/MZ (does not block Tc-99m uptake)

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84
Q

Visualization of pyramidal lobe (thyroid scan)

A

Graves disease; also seen in 10% of normal patients

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85
Q

RAIU (radioactive iodine uptake) in Graves and multinodular goiter

A

> 50% and >30%, respectively (Core Review; Prometheus says >70% and >40%)

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86
Q

Plummer disease

A

multinodular goiter or thyroid adenoma associated with hyperthyroidism

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87
Q

Panda sign DDx

A

Ga-67 scan; sarcoidosis, Sjogren’s, treated lymphoma

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88
Q

Clinical hyperthyroidism with decreased RAIU (radioactive iodine uptake)

A

subacute thyroiditis (a.k.a. de Quervain’s or granulomatous); viral etiology

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89
Q

Discordant nodule (thyroid scan)

A

lesion traps (Tc-99m hot), but does not organify (I-123/131 cold); suspicious => biopsy indicated

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90
Q

Thyroid cancer types which respond poorly to I-131 therapy

A

medullary, anaplastic, Hurthle cell

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91
Q

Diffuse Tc-99m pertechnetate uptake, but no I-123/131 uptake (thyroid)

A

congenital enzyme deficiency inhibiting organification or taking PTU (blocks organification)

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92
Q

Things that make patient I-131 treatment resistant

A

medullary, anaplastic, or Hurthle cell subtype, prior I-131 treatment (need 50% higher dose), prior MZ treatment

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93
Q

Ideal TSH prior to I-131 treatment

A

goal is 30-50 mU/L; stop levothyroxine or give recombinant TSH (thyrogen)

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94
Q

I-131 treatment dosing

A

100 mCi if cancer confined to thyroid, 150 mCi if nodal mets, 200 mCi if distant mets; 30 mCi for multinodular goiter or toxic adenoma, 15 mCi for Graves

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95
Q

I-131 treatment + lung mets

A

risk of pulmonary fibrosis

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96
Q

I-131 treatment + Sjogren’s

A

salivary gland damage (higher dose => more damage)

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97
Q

I-131 scan with liver uptake

A

post-treatment scan (always)

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98
Q

Contraindications to I-131 treatment

A

severe thyrotoxicosis (use PTU/MZ to calm down first), pregnancy

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99
Q

Lab test to monitor for thyroid cancer recurrence

A

thyroglobulin; after thyroidectomy anything >0 is abnormal (but trend is most important)

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100
Q

Wolff-Chaikoff effect

A

ingestion of large amount iodine => decreased thyroid hormone; can be used to calm down hyperthyroidism

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101
Q

Most common cause of hyperparathyroidism

A

hyperfunctioning adenoma > hyperplasia

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102
Q

Dual-phase parathyroid scan technique

A

Tc-99m sestamibi; imaging at 10 minutes and 3 hours; depends on mitochondrial density and blood flow

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103
Q

Tc-99m sestamibi scan with lymph node uptake

A

suspicious for cancer; next step is ultrasound (or other imaging modality)

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104
Q

Tc-99m sestamibi scan with breast uptake

A

suspicious for breast cancer; next step is mammogram

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105
Q

Lipophilic CNS tracers

A

Tc-99m HMPAO, Tc-99m ECD; cross BBB, used to assess perfusion (parenchymal uptake)

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106
Q

CNS tracer with slow washout

A

Tc-99m ECD, while Tc-99m HMPAO has fast washout

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107
Q

CNS studies using DTPA tracer

A

cisternogram and CSF leak studies use In-111 DTPA; shunt and brain death studies use Tc-99m DTPA (shorter half-life)

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108
Q

Ictal vs. inter-ictal seizure focus radiotracer uptake

A

ictal is hot, inter-ictal is cold

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109
Q

Which tracer is used first in Tl-201 + Ga-67 comparison study?

A

Tl-201 should be used first (otherwise downscatter from Ga-67 peaks)

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110
Q

CNS Tl-201+Ga-67: lymphoma vs. infection (e.g. toxo, abscess, crypto, TB)

A

all will be hot on Ga-67 portion, but only lymphoma will be hot on Tl-201

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111
Q

CNS tumor necrosis vs. residual/recurrent disease

A

residual or recurrent disease is Tl-201 hot, while tumor necrosis will be Tl-201 cold; similar findings on PET

112
Q

Normal variants in brain death

A

scalp activity, radiotracer in superior sagittal sinus

113
Q

Use of Diamox in CNS imaging

A

a.k.a. acetazolamide; to identify ischemic areas that may benefit from revascularization

114
Q

Effect of bright lights on PET imaging (CNS)

A

increased uptake in occipital lobes

115
Q

Decreased uptake in caudate and putamen (CNS imaging)

A

Huntington’s disease

116
Q

Pathway involved in crossed cerebellar diaschisis

A

corticopontine-cerebellar pathway (connects cerebral hemisphere to contralateral cerebellar hemisphere)

117
Q

NPH findings (CNS)

A

radiotracer in lateral ventricles at 24 hours (“heart-shaped”); NPH has a normal opening pressure on LP

118
Q

Pledget-to-plasma activity ratio in CSF leak

A

1.5:1 or greater; pledget activity is quantified using a well counter

119
Q

Distal CSF shunt obstruction findings

A

> 10 minutes without flow of radiotracer into abdomen suggests at least partial distal obstruction

120
Q

Indication for 4th phase of bone scan

A

patients with renal failure or poor soft tissue clearance (diabetics or vasculopaths) at 24 hours; normal delayed phase is at 3 hours

121
Q

Uptake in thyroid, stomach, lungs, liver, and kidneys on bone scan

A

metastatic calcification (CKD, hyperparathyroidism, multiple myeloma, hypervitaminosis D)

122
Q

Particle released during I-131 treatment (decay type)

A

beta particle (beta-minus decay)

123
Q

Collimator used for thyroid imaging

A

pinhole

124
Q

Three forms of subacute thyroiditis

A

granulomatous (painful, de Quervain’s), lymphocytic (painless), postpartum

125
Q

Patient post-ablation for papillary thyroid cancer with increasing thyroglobulin and negative I-123 scan - NEXT STEP

A

FDG PET; if there is recurrent cancer which has de-differentiated, it will be hot on PET (papillary is normal not active on PET)

126
Q

Most common cause of false positive parathyroid scintigraphy

A

thyroid adenoma (hot thyroid nodule)

127
Q

Difference between solid and liquid curves (gastric emptying)

A

solids have a lag phase

128
Q

Normal gastric emptying thresholds

A

<90% remaining at 1 hour, <60% at 2 hours, <30% at 3 hours, <10% at 4 hours (most sensitive time point for gastroparesis)

129
Q

Rapid emptying on gastric emptying study

A

rapid emptying <30% remaining at 1 hour (or <70% at 30 minutes according to Crack)

130
Q

Medications to stop before gastric emptying study

A

stop 2 days prior; pro-motility agents (e.g. metoclopramide, erythromycin), opiates, CCBs, anticholinergics (e.g. bentyl)

131
Q

Sensitivity of tagged-RBC scan vs. angiography

A

tagged RBC is 0.1-0.2 ml/min, angiography is 1.0 ml/min; sulfur colloid is even more sensitive than tagged RBC

132
Q

RBC tagging: in vivo labeling

A

inject stannous ions => wait 30 min => inject Tc-99m pertechnetate; end up with lots of free pertechnetate and a dirty image

133
Q

Causes of in vivo or modified RBC labeling failure

A

drug interactions (e.g. heparin), heparinized tubing, recent IV contrast administration

134
Q

RBC tagging: modified approach

A

inject stannous ions => wait 30 min => draw 5 cc of blood => add Tc-99m pertechnetate => re-inject

135
Q

RBC tagging: in vitro labeling

A

draw 5 cc of blood => add stannous ions and pertechnetate => re-inject

136
Q

RBC tagging: best to worst methods

A

in vitro (best) > modified > in vivo (worst); based on labeling efficiency

137
Q

Gastric activity on GI bleeding scan

A

gastric bleed or free pertechnetate (check thyroid and salivary glands)

138
Q

HIDA scan for patient with hyperbilirubinemia

A

higher dose of radiotracer required

139
Q

HIDA scan prep

A

fast for >4 hours, but eaten within 24 hours (give CCK if >24 hours or on TPN); phenobarbitol in neonates

140
Q

Dose of phenobarbitol for HIDA scan (neonate)

A

5 mg/kg for 5 days (split into 2 doses per day)

141
Q

No gallbladder activity on HIDA at 1 hour - NEXT STEP

A

wait an additional 3 hours, or give morphine and wait 30 minutes (must see bowel activity before giving morphine)

142
Q

Rim sign (HIDA)

A

suggests acute cholecystitis, possibly gangrenous

143
Q

Acute cholecystitis on HIDA scan

A

no gallbladder activity after 4 hours, or 1 hour + 30 minutes after giving morphine

144
Q

Chronic cholecystitis on HIDA scan

A

gallbladder activity at >1 hour (either while waiting 3 more hours or after giving morphine), or EF <35% after CCK administration

145
Q

Dose of sinaclide for HIDA scan

A

a.k.a. CCK; 0.02 ug/kg (slow infusion); if administered pre-exam, need to wait 2 hours before starting exam

146
Q

Dose of morphine for HIDA scan

A

0.04 mg/kg (max of 4 mg)

147
Q

Normal timing of liver and gallbladder activity on HIDA scan

A

5 minutes and 15 minutes, respectively

148
Q

Most common finding in chronic cholecystitis on HIDA scan

A

normal HIDA scan

149
Q

Causes of false positive HIDA scan

A

meal within <4 hours, fasting >24 hours, CCK immediately before exam, TPN, pancreatitis, chronic cholecystitis, severe illness

150
Q

Causes of false negative HIDA scan

A

acalculous cholecystitis, duodenal diverticulum or biliary cyst simulating gallbladder

151
Q

Poor hepatic extraction and non-visualization of biliary tree on HIDA scan (adult)

A

hepatocyte dysfunction or common duct obstruction (former will empty into bowel on 24 hour delayed phase, while latter will not)

152
Q

Focal photopenic defect in liver on HIDA scan

A

cyst, mass (HCC, adenoma), abscess

153
Q

Focal liver uptake on HIDA scan

A

FNH

154
Q

Reappearing liver sign on HIDA scan

A

bile leak

155
Q

Focal liver uptake on sulfur colloid scan

A

FNH, regenerative nodule (in cirrhosis), Budd-Chiari syndrome (caudate lobe)

156
Q

Focal liver uptake on tagged RBC scan

A

hemangioma (on delayed phase, not flow or blood pool); angiosarcoma could be hot on blood pool and delayed phases

157
Q

Focal liver uptake on Ga-67 scan

A

HCC, abscess

158
Q

Particle size for sulfur colloid scan

A

0.1 to 1.0 micrometers (if too big spleen will eat them)

159
Q

Increased splenic and marrow activity on sulfur colloid scan

A

colloid shift due to hepatic dysfunction (cirrhosis, diffuse mets), diabetes, or blunt splenic trauma

160
Q

Diffuse pulmonary activity on sulfur colloid scan

A

aluminum contamination, cirrhosis, LCH, COPD with superimposed infection

161
Q

Renal activity on sulfur colloid scan

A

CHF, rejection (for transplants)

162
Q

Test(s) for ectopic splenic tissue (e.g. intrapancreatic, accessory)

A

heat-damaged RBC scan, sulfur colloid scan

163
Q

Normal distrbution of Tc-99m HMPAO vs. ECD (brain)

A

HMPAO favors frontal lobes, thalami, and cerebellum; ECD favors parietal and occipital lobes; need to use same agent across examinations

164
Q

Normal DaT scan in patient with a movement disorder

A

suggests essential tremor

165
Q

Abnormal DaT scan

A

Parkinsonian syndrome; decreased uptake in posterior putamen which progresses anteriorly as disease progresses

166
Q

Timing of FDG-PET post-chemotherapy to avoid false positive or negative

A

2-3 weeks after treatment; false positive from inflammatory changes, false negative from stunning

167
Q

Timing of FDG-PET post-radiation to avoid false positive or negative

A

2-3 months affter treatment; false positive from inflammatory changes, false negative from stunning

168
Q

Ventilation study with tracer in airway and/or stomach

A

Tc-99m DTPA clumping (aerosol)

169
Q

Perfusion scan (MAA) with renal and/or thyroid uptake - NEXT STEP

A

planar images of brain (to differentiate free pertechnetate from right-to-left shunt)

170
Q

Indications for anterior projection in renal scintigraphy

A

horseshoe kidney, transplant kidney

171
Q

Timing of cortical and clearance phases (renal scintigraphy)

A

1-3 minutes and 3+ minutes, respectively

172
Q

Decreased renal tracer uptake DDx

A

renal artery thrombosis, renal vein thrombosis, high grade obstruction, acute rejection, acute pyelonephritis, poor bolus (symmetric)

173
Q

ATN vs. acute rejection (renal scintigraphy)

A

ATN shows normal perfusion + delayed excretion; acute rejection shows delayed perfusion + delayed excretion

174
Q

20/3 or 20/peak ratio (renal scintigraphy)

A

to quantify tracer retention; compare counts at 20 minutes to counts at 3 minutes or peak count; <0.3 for normal MAG3 scan

175
Q

Diuretic renogram technique

A

normal renogram => at 20 minutes inject 40 mg lasix; clearance half-time <10 minutes after lasix is normal, >20 minutes suggests obstruction

176
Q

Causes of false positive diuretic renogram

A

poor response to lasix (renal failure), dehydration, reservoir effect, back pressure from neurogenic or full bladder

177
Q

Radiotracer with a lower peak on captopril renogram

A

DTPA will demonstrate decreased uptake in affected kidney (compared to MAG3)

178
Q

Findings in positive captopril renogram (DTPA and MAG3)

A

DTPA shows decreased uptake in affected kidney after captopril; MAG3 demonstrates marked tracer retention after captopril

179
Q

When to stop ACE inhibitor prior to captopril renogram?

A

3-5 days prior; also need to be NPO for 6 hours, stop CCBs also

180
Q

Causes of false positive captopril renogram

A

dehydration, CCBs, captopril-induced hypotension; consider false positive especially if bilateral (more common than bilateral RAS)

181
Q

Immediate post-op complications of renal transplant

A

ATN vs. acute rejection (as far as scintigraphy)

182
Q

Normal perfusion + delayed excretion in a long-standing renal transplant (renal scintigraphy)

A

cyclosporin toxicity (looks like ATN but not acute)

183
Q

Urinoma vs. hematoma vs. lymphocele (renal transplant scintigraphy)

A

urinoma = <2 weeks, tracer between kidney and bladder; hematoma = <2 weeks, photopenic area; lymphocele = >4 weeks, photopenic area

184
Q

Photopenic area on DMSA renal scintigraphy

A

acute = pyelonephritis; chronic = mass or scarring (scarring is associated with volume loss)

185
Q

Halo of activity with central photopenia (testicular scintigraphy)

A

late/missed torsion or testicular abscess; acute torsion demonstrates total absence of activity; tracer is Tc-99m pertechnetate

186
Q

Radionuclide cystography (RNC)

A

to evaluate for reflux; pertechnetate, DTPA, or sulfur colloid; grade 1 is ureter only, grade 2 is pelvicalyceal, grade 3 is tortuous ureter and/or pelvicalyceal dilatation

187
Q

FDG uptake biology

A

enters cell via GLUT1 => phosphorylated by hexokinase to form FDG-6-phosphate

188
Q

Cause(s) of artificially low SUVs (PET)

A

high blood glucose (competition)

189
Q

PET with diffuse muscle uptake

A

recent insulin administration or recent meal; consider rhabdomyolysis (distribution dependent)

190
Q

PET with increased colonic uptake

A

metformin; may see small bowel uptake as well

191
Q

PET cold tumors

A

BAC, carcinoid, RCC, prostate, mucinous neoplasms, peritoneal implants

192
Q

Focal thyroid uptake (PET)

A

suspicious for malignancy; needs further workup (ultrasound)

193
Q

Diffuse thyroid uptake (PET)

A

most commonly Hashimoto’s

194
Q

RCC vs. oncocytoma (PET)

A

RCC is cold, oncocytoma is hot

195
Q

Cold ground glass nodule (PET)

A

cancer

196
Q

Hot ground glass nodule (PET)

A

infection

197
Q

Seminoma vs. NSGCT (PET)

A

seminoma is hot, NSGCT is cold; true for retroperitoneal mets as well

198
Q

PET hot ovaries in post-menopausal patient

A

suspicious for malignancy; needs ultrasound

199
Q

Adrenal uptake on PET

A

mild is normal; if adrenal is hotter than liver => suspicious for malignancy

200
Q

Thymic rebound vs. recurrent lymphoma

A

thymic rebound may be warm, lymphoma is HOT (super hot)

201
Q

Solitary pulmonary nodule on PET

A

8 mm is smallest size that can be reliably evaluated; active granulomatosis disease may be a false positive

202
Q

Perchlorate

A

a.k.a. Lugol’s solution or SSKI

203
Q

Skeletal uptake on MIBG scan

A

bone mets (especially neuroblastoma)

204
Q

Medications to hold prior to MIBG

A

CCBs, labetalol, TCAs, reserpine, sympathomimetics; other beta-blockers are ok to continue

205
Q

Studies that may show brown fat

A

PET, MIBG

206
Q

Islet cell tumor subtype with poor In-111 pentetreotide uptake

A

insulinoma

207
Q

When to stop octreotide medication prior to In-111 pentetreotide scan?

A

3 days prior to scan

208
Q

Best study for a non-functioning islet cell tumor

A

PET

209
Q

In-111 pentetreotide is most sensitive for what neoplasms?

A

carcinoid, paraganglioma (extra-adrenal pheo), islet cell tumors (not insulinoma), medullary thyroid cancer

210
Q

Indication for ProstaScint

A

to evaluate for soft tissue prostate mets (rising PSA + negative bone scan)

211
Q

Radiotracer for ProstaScint

A

In-111 capromab pendetide; critical organ is liver

212
Q

Radiotracer for lymphoscintigraphy + particle size

A

Tc-99m sulfur colloid; 100-200 nm particles

213
Q

Lymphoscintigraphy technique for breast cancer or melanoma

A

inject superfical or deep to lesion for breast cancer; intradermal injection at 4 sites around lesion for melanoma

214
Q

Breast-specific gamma imaging technique

A

inject Tc-99m sestamibi in contralateral arm (or foot if imaging both breasts)

215
Q

False positives in breast-specific gamma imaging

A

fibroadenoma, fibrocystic change, inflammation

216
Q

Lymph node uptake on breast-specific gamma imaging

A

highly suspicious for spread of malignancy

217
Q

Study that uses Tc-99m mebrofenin or disofenin

A

HIDA scan

218
Q

Best radiotracer for determination of differential renal function

A

DMSA > MAG3

219
Q

Study type to detect H. pylori

A

C-14 urea breath test

220
Q

Cardiac nucs: photopenic area on stress that improves on rest

A

reversible defect (ischemic myocardium)

221
Q

Cardiac nucs: photopenic area on stress and rest

A

fixed defect (hibernating myocardium or infarct/scar); need viability portion to differentiate

222
Q

Cardiac nucs: perfusion agents

A

Tc-99m sestamibi/tetrofosmin, rubidium-82, Tl-201, nitrogen-13 ammonia

223
Q

Cardiac nucs: stress agents

A

adenosine, dipyridamole, regadenoson, dobutamine

224
Q

Cardiac nucs: normal myocardial perfusion with abnormal wall motion

A

stunned myocardium (acute phenomenon)

225
Q

Cardiac nucs: fixed defect with abnormal wall motion

A

hibermating myocardium (chronic ischemic process) or infarct/scar

226
Q

Cardiac nucs: LV cavity larger on stress images

A

transient ischemic dilation (left main or 3-vessel disease)

227
Q

Cardiac nucs: fixed LV dilation on stress and rest

A

dilated cardiomyopathy

228
Q

Cardiac nucs: RV activity on rest

A

RV hypertrophy

229
Q

Cardiac nucs: defect on rest that improves with pharmacologic stress

A

vasospasm (improves with administration of vasodilators)

230
Q

Cardiac nucs: purpose of viability portion

A

to identify areas of viable myocardium that may benefit from revascularization (hibernating myocardium)

231
Q

Cardiac nucs: fixed perfusion defect that takes up FDG

A

mismatch; indicates viable myocardium (hibernating); will take up FDG and redistribute Tl-201

232
Q

Vasomotor nephropathy (renal scintigraphy)

A

a.k.a. ATN or delayed graft function or ischemic nephropathy (all are synonyms)

233
Q

Cardiac nucs: fixed perfusion defect that does not take up FDG

A

matched defect; indicates non-viable myocardium (infarct/scar)

234
Q

Cardiac nucs: viability agents

A

FDG PET, Tl-201

235
Q

Cardiac nucs: elevated lung-heart ratio (thallium)

A

> 0.45 correlates with multivessel or high-grade LAD/LCx disease; occurs on stress images

236
Q

Cardiac nucs: % coronary stenosis for perfusion defect

A

50% stenosis during stress, 90% stenosis at rest

237
Q

Cardiac nucs: medications to discontinue prior to exam

A

CCBs, beta-blockers, and long-acting nitrates should be stopped 24 hours before; NPO for 4 hours; no caffeine

238
Q

Cardiac nucs: bronchospasm

A

dipyridamole > regadenoson (adenosine has a super short half-life); Tx albuterol

239
Q

Cardiac nucs: known LBBB

A

need pharmocologic stress test (not exercise); don’t use dobutamine (more false positives)

240
Q

Cardiac nucs: reversible perfusion defect in anterior septal region

A

suspicious for LBBB (false positive); occurs more often with dobutamine or exercise stress

241
Q

Cardiac nucs: fixed defect with surrounding reversible defect

A

infarct with peri-infarct ischemia

242
Q

Cardiac nucs: too much liver or bowel activity

A

patient is not exercising hard enough

243
Q

What is a MUGA scan?

A

tagged RBCs used to estimate cardiac EF; MUlti-Gated Acquistion

244
Q

Photopenic halo around cardiac blood pool (MUGA)

A

pericardial effusion

245
Q

Cause(s) of falsely low EF on MUGA

A

incorrect LAO view resulting in overlapping structures (e.g. LA, RV)

246
Q

Cause(s) of falsely high EF on MUGA

A

incorrect background ROI (may be drawn over spleen)

247
Q

MUGA EF equation

A

EF = (end-diastolic counts - end-systolic counts) / (end-diastolic counts - background counts)

248
Q

Cardiac nucs: fixed anterior or anteroseptal wall defect

A

consider breast attenuation artifact (check ECG and wall motion)

249
Q

Cardiac nucs: fixed inferior wall defect

A

consider diaphragmatic attenuation artifact (check ECG and wall motion)

250
Q

Cardiac nucs: apical thinning

A

normal variant

251
Q

Cardiac nucs: indications for dobutamine stress

A

patients with asthma or COPD, or who had caffeine within 12 hours prior

252
Q

Cardiac nucs: antidote for dipyridamole

A

aminophylline (shorter half-life than dipyridamole => must continue to monitor)

253
Q

Cardiac nucs: contraindications to adenosine/dipyridamole stress

A

severe COPD, asthma, 2nd/3rd degree heart block, recent caffeine or aminophylline

254
Q

Cardiac nucs: contraindications to regadenoson stress

A

history of seizures is a relative contraindication (lowers seizure threshold)

255
Q

Cardiac nucs: D-shaped LV

A

RV hypertrophy (causing septal flattening)

256
Q

Cardiac nucs: normal perfusion with decreased EF

A

consider non-ischemic cardiomyopathy

257
Q

Approved agents for treatment of bone pain from breast/prostate mets

A

Ra-223 (xofigo) > Sm-153 (quadramet) > Sr-89 (metastron); best to worst

258
Q

Contraindications to Sr-89 and Sm-153 treatment

A

pregnant, breastfeeding, GFR <30

259
Q

Decay type of bone pain agents

A

alpha decay = Ra-223; beta-negative decay = Sm-153, Sr-89

260
Q

Side effect of Sr-89 and Sm-153

A

bone marrow suppression; Sm-153 has less than Sr-89 => 6-8 weeks vs. 8-12 weeks for full recovery

261
Q

Y-90 particle size

A

20-40 micrometers; Y-90 is a pure beta emitter

262
Q

Y-90 imageable energy peaks

A

175 keV, 185 keV

263
Q

Radioimmune therapy (RIT)

A

for treatment of NHL; In-111 ibritumomab tiuxetan (Zevalin) given to evaluate tumor burden, then give Y-90 labeled antibody if biodistribution is ok; antibody binds to CD-20 receptors

264
Q

Altered biodistributions for RIT (reasons not to treat)

A

lung > heart (day 1), lung > liver (day 2-3), kidneys > liver (day 3), fixed bowel uptake, bowel > liver, or bone marrow uptake >25%

265
Q

Most common side effect of RIT

A

thrombocytopenia, neutropenia

266
Q

Diffuse soft tissue uptake on bone scan + no kidneys visualized

A

renal failure

267
Q

Ga-67 hot + Tl-201 cold DDx

A

TB, atypical mycobacteria, PCP, toxoplasmosis

268
Q

Ga-67 cold + Tl-201 hot DDx

A

Kaposi sarcoma

269
Q

Salivagram technique

A

Tc-99m sulfur colloid administered PO to evaluate for aspiration

270
Q

Interventions to reduce brown fat uptake

A

increase ambient temperature, administer beta-blocker or benzodiazepine

271
Q

Most common cold nodule (thyroid)

A

benign colloid cyst

272
Q

Indication to stop doxorubicin due to cardiotoxicity (MUGA findings)

A

relative drop in LVEF of >10% from previous plus an absolute LVEF of <50% is an indication to stop treatment

273
Q

Mickey mouse sign (bone scan)

A

Paget disease

274
Q

Cardiac uptake on bone scan

A

infarction, myocarditis, pericarditis, amyloidosis

275
Q

Adequate percent of maximum HR for exercise stress

A

85%; max HR = 220-age

AJT CORE (12 decks)

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