Bone Classic NM Flashcards

1
Q

Osteoblast:
Function
Stimulated by

A

Synthesize bone matrix - - bone formation
PTH, prostaglandin, growth factor

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2
Q

Matrix constituent

A

Collagen I
Non-collagen proteins 10-15%
Elasticity and flexibility

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3
Q

Osteoclasts
Function
Regulation

A

Bone remodeling - - remove old bone - - release Ca
PTH, TGF, TNF, interleukin 1,6
Vit D stimulate
Calcitonin inhibit
Age, osteoporosis, fractures, myeloma, MTS

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4
Q

Cortical bone

A

80-90% calcified
Female lose after 40 years
Thick at diaphysis
Thin at epiphysis - - trabecular bone, 15-25 % calcified
Female lose after menopause

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5
Q

Ca level

A

Soft tissue - low level 0.005%
Bone - high level 14-24%

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6
Q

Degree of uptake

A

bone perfusion,
nature of Ca-P deposits (size, hydration status, Ca/P ratio), osteoblastic/osteoclastic metabolic activity

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7
Q

Three-phase scan

A

dynamic (30-60 frames of 1-2 sec)
BP (3-5 min, matrix 128×128 or 256×256, zoom factor 1.33) 5-10 min after injection
delayed 3 hours after

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8
Q

Quantitative SPECT

A

after 3 h vertebral radioactivity 50 KBq/mL = SUV 6

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9
Q

Trabecular bone

A

higher retention index than cortical
femur (thick cortex) has lower retention index than ribs

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10
Q

Metaphysis

A

14.3% Ca content, rich vascularization, high metabolic activity
higher dose than diaphysis

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11
Q

Dose MDP

A

Adult 500 MBq 13 mCi,
children min 40 MBq

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12
Q

Total-body image

A

matrix 256×1024 or 512×2048
zoom factor 1
scanning speed 10-15 cm/min (>1.5 mln counts ant and post)
sequential image (acquisition at the end) or continuous image (adults)

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13
Q

Planar image

A

matrix 128×128 or 256×256
zoom factor 1.33
predefined acquisition time 4-10 min or number of counts
pinhole collimator for small structures (50000-100000 counts)

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14
Q

SPECT

A

step-and-shot modality
60 or 64 frames per detector head, each 10-30 sec
matrix 128×128, pixel size 4.6×4.6 mm acquisition time increased 30-40 sec per angular view when low counts (skull)

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15
Q

Renal or heart failure, obesity and advanced age

A

↑dose and time
affect quality of image

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16
Q

incomplete labeling if air is introduced into the vial

A

free pert
uptake in thyroid, stomach

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17
Q

Excess Al from generator

A

colloid – accumulate in liver

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18
Q

Bones poorly visualized posterior

A

wrong energy

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19
Q

Spine is not visualised

A

inadequate counts

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20
Q

ROI counts
Skull and large joints
Thoracoabdominal region
Distal joints

A

250000-400000
700000-1000000
150000-250000

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21
Q

F-fluoride similar to MDP

A

Deposits on hydroxyapatite surface of newly forming bone – Exchange of F with hydroxyl group of hydroxyapatite crystals – fluorapatite
50% absorbed by bone
Adult dose 4 mSv (MDP 3 mSv)

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22
Q

Fluoride unlike MDP

A

Waiting time 15-30 min vs 3h
Aquisition time 15-30 min vs 40 min
Children dose 3.5 mSv vs 2 mSv

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23
Q

Partial extravasation

A

visualization of LN

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24
Q

Injection in artery

A

intense tracer accumulation in portion of arm distal from injection (evening glove)

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25
Q

Focal soft tissue spot

A

intramuscular injection, hematoma, severe renal failure, hypercalcemia

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26
Q

X-ray positive

A

Bone density reduction 30-75% required

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27
Q

Bone scan positive

A

5-10% bone destruction required

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28
Q

Fibrous bone dysplasia

A

congenital
bone replaced with fibrous-like tissue
Polyostotic ass with McCune-Albright or Mazabraud sy (intramuscular myxoma – FDG)
malignant degeneration 1% – FDG

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29
Q

Fibrous bone dysplasia
Bone scan

A

Skull (pirate sign), ribs, femur
Areas of reduced uptake + increased uptake

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30
Q

Giant Cell Tumor

A

fusion of growth plate
extend from metaphysis to epiphysis of knee
Benign, osteolytic – transform into sarcoma (no MTS – quasi-malignant)

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31
Q

Giant cell tumor FDG

A

Doughnut sign
Regional hyperemia - - diffuse uptake
Extremely avid

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32
Q

Non-ossifying fibroma

A

cortical lesion of long bones
regress spontaneously

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33
Q

Non-ossifying fibroma Bone scan

A

normal (osteolytic)
Ringlike pattern around photopenic lesion
Calcification – uptake

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34
Q

Myositis ossificans

A

secondary to contusion, trauma
high uptake on bone scan

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35
Q

MTS

A

Bone pain, path fracture, cord compression
↑ AlcPhos, hypercalcemia, bone marrow aplasia
Hematogenous spread – not joints – axial skeleton (prox humerus, femur)

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36
Q

Risk Prostate Ca bone MTS

A

PSA>10,
Gleason>8, locally advanced,
↑ AlcPhos,
bone pain

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37
Q

Lytic MTS

A

RCC, ATC, neuroblastoma, lung, MM, lymphoma

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38
Q

Hypertrophic pulmonary osteoarthropathy

A

Primary – pachydermoperiostosis
Secondary – lung ca (NSCLC), bronchiectasis, emphysema
tram line sign

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39
Q

MTS Bone scan

A

Multiple asymmetric focal lesions:
spine>sternum>ribs> long bones>skull
MTS>arthritis>trauma> Paget>MBD>OM
Spine MTS: body and pedicles
FDG :DD MTS vs osteoporosis – no uptake in osteoporosis

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40
Q

Superscan MTS

A

↓ uptake in soft tissue and nephron-urinary tract
long bones, skull, no kidneys
DD hyperpara

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41
Q

MTS Intensive uptake >6m

A

progression

42
Q

Radio changes Bone scan

A

within weeks - inflammation
after months - fibrotic change and ↓BP

43
Q

Postchemo Bone scan

A

↑ uptake in kidneys

44
Q

Flare phenomenon

A

2w-3m – good response – ↑pain
2-6m –↑ sclerosis (max 4-8w)
4-6m after flare – regress activity

45
Q

Degeneration

A

Joint - destroy
Spine - intervertebral disk - lose height
Cartilage - thin joint space
Osteophyte - joint instability
Facet - L5-S1 bilateral
Spondylolystesis - anterior displacement of vertebra

46
Q

Degeneration Bone scan

A

Not all sites are metabolically active
Linear uptake - vertebral collapse
Disc space - discitis
Focal in vertebral body - Schmorl’s node
Cystic changes + loss of joint space = osteoarthritis
“salt and pepper” in vertebral body - hemangioma

47
Q

Metabolic Bone Disease

A

Osteoporosis
Osteomalacia
Hyperpara
Renal osteodystrophy

48
Q

Osteoporosis Bone scan

A

postmenopausal/ senile
DEXA the best
Bone scan not specific, usually normal
reduced bone-to-soft tissue ratio,
↓ resolution of vertebral body endplates,
↑ diffuse skull uptake
Indication: assess complications (path fracture)

49
Q

Sacral insufficiency fracture

A

Honda sign

50
Q

Osteomalacia
Bone scan

A

deficit of P, Ca, vit D – abnormal mineralization
Femoral neck fracture
Pelvic occult fracture
Bone scan normal
later chicken bone
Like hyperpara: increased bone-to-soft tissue ratio, uptake in long bones, skull, sternum

51
Q

Bisphosphonate therapy

A

weaken bone – possible fracture – MDP

52
Q

Rickets

A

bowed legs, costochondral swelling

53
Q

Oncogenic osteomalacia

A

ass with mesenchymal tumor – paraneoplastic sy – detect first primary by FDG, DOTA, DOPA

54
Q

Hyperpara

A

↑PTH – loss of Ca from bone – weaken bone – hypercalcemia

55
Q

Primary hyperpara

A

PTA – MIBI

56
Q

Secondary hyperapa

A

vit D def, CKD, low Ca – hyperstimulation

57
Q

Tertiary hyperpara

A

autonomous

58
Q

Hyperpara ass with brown tumor

A

replacement of bone with hemorrhage and granulation tissue
MIBI, FDG

59
Q

Hyperpara ass with metastatic calcification

A

uptake in soft tissue, lung, thyroid, stomach
fractures

60
Q

Hyperpara Bone scan

A

skull (grenadier soldier), jaw, sternum (tie sign), shoulder, rosary beads sign, uptake in stomach

61
Q

Renal osteodystrophy
Bone scan

A

metabolic changes incl secondary hyperpara
skull, jaw, very high bone-to soft tissue ratio, uptake in lung, stomach, kidneys (calcifications)
No uptake in bladder

62
Q

Paget

A

Diff blast/clast activity towards bone resorption
↑ vascularization
Lytic, mixed, sclerotic phase
↑AlcPhos
Mono/polyostotic (malignant transformation <1% – low FDG)

63
Q

Paget X-ray

A

Bone deformation
Cortex thickening
Lytic lesions as “flame”

64
Q

Paget Bone Scan + FDG

A

Most sensitive
Vertebra – “picture frame”
“mickey mouse”, “ivory sign”, bowed long bones (– insufficiency fracture)
Complication – nonunion fracture
FDG:
DD MTS vs Paget
DD Fibrous dysplasia vs Paget – young age, bowing legs, ground glass

65
Q

Fatigue fracture

A

abnormal load on normal bone
athlete or military

66
Q

Female athlete triad

A

eating disorder, amenorrhea, osteoporosis

67
Q

Insufficiency fracture

A

normal load on weaken bone
osteoporosis, RA, MBD, neuro, radio, THR, steroid, fluoride therapy, bisphosphonate

68
Q

Athlete + lumbar back pain

A

spondylolysis
bilateral – spondylolisthesis

69
Q

Fracture bone scan

A

Acute 1-4w - ↑ blood flow and BP
Subacute 6-12w - bone callus, ↓blood flow
Healing - callus resorbed – reduce uptake – normal in 1-2y
Negative scan + positive X-ray – healed fracture – exclude spondylolysis

70
Q

Stress fracture

A

pain upon activity and point tenderness – relieved with rest
Proximal tibia heal faster
Anterior aspect and malleolus – complications – non-conjunction, poor positioning, AVN
Avoid exercise 6w

71
Q

Stress fracture X-ray

A

Linear sclerosis

72
Q

Stress fracture Bone scan

A

3-phase scan – 100% sensitive
Positive 2 weeks before X-ray
Tibia, metatarsal bones
Focal area of hyperactivity
Grade I-IV

73
Q

Shin Splint

A

insertion tendopathy
Abnormal movement of muscles
continue exercise while comfortable

74
Q

Shin splint Bone scan

A

Linear or patchy uptake
Posterior tibial cortex
Vascular and BP normal
Important lateral views

75
Q

AVN

A

Aseptic necrosis – several days after insult – reparation – cold-in-hot spot
Bone infarct: alco, sickle cell anemia, radio, cytotoxic, steroids

76
Q

Hip AVN

A

dislocation of hip, femoral neck fracture, steroids, alco, collagen vascular disease, hemoglobinopathies, Gaucher disease, skeletal dysplasia
Children 4-8y - Legg-Calve-Perthes disease
80% bilateral

77
Q

Osteochondrosis dissecans

A

bone fragmentation of joint end

78
Q

AVN Bone Scan

A

focal area of reduced uptake - non-perfused bone
Fracture – sudden reduction of blood flow – photopenic
After steroids – small photopenic lesion + microfractures and repair – increased uptake

79
Q

AVN MRI

A

Most sensitive and specific for osteonecrosis
DD transient osteoporosis vs subchondral insufficiency fracture

80
Q

Sympathetic reflex dystrophy
Bone scan

A

Sudeck’s sy
post-traumatic pain, swelling, skin dystrophy
3-phase scan: ↑ blood flow and capillary permeability in first 2-3m
up to 1y ↑ uptake in periarticular region
Children: low uptake in hip

81
Q

RA

A

Autoimmune inflammatory polyarthritis
Articular deformity
Small joints in hand and feet symmetrical

82
Q

RA US

A

Early-stage arthrosynovitis, tendosynovitis

83
Q

RA Bone scan

A

Limited
Detect early joint involvement
degree of uptake proportional to activity of disease
Bone erosion – intense uptake on background of diffuse increased uptake
Corticosteroid – complications (X-ray still negative) – fracture
Early stage Fluoride>MDP

84
Q

Seronegative Spondyloarthropathy

A

Ankylosing spondylitis, psoriatic arthropathy, Reiter sy, IBD
No RA (anti-IgG) – HLA-B27
Feature of enthesitis: inflammation, degeneration of insertion site of tendon – dystrophic ossification

85
Q

Seronegative Spondyloarthropathy spine

A

syndesmophytes (vertical osteophytes)

86
Q

Seronegative Spondyloarthropathy Bone Scan

A

3-phase scan:
level of enthesis – early diagnosis of sacroiliitis
Spondyloarthritis – sternal, costotransverse, sacroiliac bones

87
Q

Seronegative Spondyloarthropathy MRI

A

Preferred – morphological evidence of degeneration

88
Q

Osteomyelitis

A

Maxilla, mandible, long bones, spine – ↑ blood supply

89
Q

Osteomyelitis X-ray

A

Normal 2-4w
Later – cortical erosion, bone destruction, gas in soft tissue

90
Q

OM Bone Scan

A

Low probability – 3-phase scan – negative – exclude inflammation or infection
Positive – inflammation (nonspecific for infection)
Spinal OM: false-negative due to regional ischemia – remain abnormal due to bone remodeling – false-positive

91
Q

OM MRI

A

dd necrotic tissue – detect presence of air, gas bubbles – septic involvement of joint space, joint effusion and synovial thickening

92
Q

OM Tc-HMPAO WBC

A

positive 3-phase scan doesn’t exclude infection
Gold standard for neutrophil-mediated infection
combi with Tc-colloid if equivocal – colloid doesn’t accumulate in OM

93
Q

OM Radiolabeled anti-granulocyte monoclonal antibody

A

bone marrow accumulation higher than in vitro labeled WBC
imaging of chronic OM

94
Q

OM FDG

A

Equivocal WBC – FDG
Esp if neutropenia
>MRI in spondylitis
>Ga in paraspinal soft tissue infection
>bone scan in DD advanced arthritis vs infection

95
Q

Spondylodiscitis

A

2 vertebra+disc
Staph aureus

96
Q

Spondylodiscitis Bone scan

A

Low specificity 40%
Ga combi + MDP – specificity 65-80%
Esp postop infection MDP>Ga – degenerative
Ga>MDP – vertebral infection

97
Q

Spondylodiscitis MRI

A

Positive in first 2w
Gold standard for spine infection
Overestimation of extent – unnecessary surgery

98
Q

Spondylodiscitis FDG

A

Low specificity
Response to treatment – score 0-4
DD infection vs neoplastic lesion or degenerative

99
Q

Prosthetic joint implants

A

Infection 2%
after revision 20%
Early <3m - Staph aureus
Delayed 3-24m - Co-neg staph
Late >24m - remote infection
Aseptic - <10% neutrophils
Inflammation – neutrophils

100
Q

Prosthetic joint implants X-ray

A

Not affected by metal
Negative for 4 weeks
Later – radiolucent area around – loosening

101
Q

Prosthetic joint implants Bone Scan

A

3-phase negative – exclude infection
Bone remodeling 1 year – false-positive
Uptake at metal – loosening
3-phase positive – inflammation (nonspecific for infection)
Cemented – within 1year normal scan
Non-cemented –>2year non-specific uptake
Hip –>2 years – 3-phase scan or FDG
Knee –>5y (uptake persist longer – bone scan less useful)

102
Q

Prosthetic joint implants Tc-HMPAO-WBC

A

3-phase positive –DD aseptic loosening vs infection
Hip >2y – positive 3-phase – suspected acute –WBC>antigranulocyte
Within 2y – WBC + combi with bone marrow scan
Knee – WBC preferred or combi
Study of choice for infection
Suspected chronic – anti-granulocyte>WBC