Bone Classic NM Flashcards
(102 cards)
1
Q
Osteoblast:
Function
Stimulated by
A
Synthesize bone matrix - - bone formation
PTH, prostaglandin, growth factor
2
Q
Matrix constituent
A
Collagen I
Non-collagen proteins 10-15%
Elasticity and flexibility
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
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
5
Q
Ca level
A
Soft tissue - low level 0.005%
Bone - high level 14-24%
6
Q
Degree of uptake
A
bone perfusion,
nature of Ca-P deposits (size, hydration status, Ca/P ratio), osteoblastic/osteoclastic metabolic activity
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
8
Q
Quantitative SPECT
A
after 3 h vertebral radioactivity 50 KBq/mL = SUV 6
9
Q
Trabecular bone
A
higher retention index than cortical
femur (thick cortex) has lower retention index than ribs
10
Q
Metaphysis
A
14.3% Ca content, rich vascularization, high metabolic activity
higher dose than diaphysis
11
Q
Dose MDP
A
Adult 500 MBq 13 mCi,
children min 40 MBq
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)
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)
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)
15
Q
Renal or heart failure, obesity and advanced age
A
↑dose and time
affect quality of image
16
Q
incomplete labeling if air is introduced into the vial
A
free pert
uptake in thyroid, stomach
17
Q
Excess Al from generator
A
colloid – accumulate in liver
18
Q
Bones poorly visualized posterior
A
wrong energy
19
Q
Spine is not visualised
A
inadequate counts
20
Q
ROI counts
Skull and large joints
Thoracoabdominal region
Distal joints
A
250000-400000
700000-1000000
150000-250000
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)
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
23
Q
Partial extravasation
A
visualization of LN
24
Q
Injection in artery
A
intense tracer accumulation in portion of arm distal from injection (evening glove)
25
Focal soft tissue spot
intramuscular injection, hematoma, severe renal failure, hypercalcemia
26
X-ray positive
Bone density reduction 30-75% required
27
Bone scan positive
5-10% bone destruction required
28
Fibrous bone dysplasia
congenital
bone replaced with fibrous-like tissue
Polyostotic ass with McCune-Albright or Mazabraud sy (intramuscular myxoma -- FDG)
malignant degeneration 1% -- FDG
29
Fibrous bone dysplasia
Bone scan
Skull (pirate sign), ribs, femur
Areas of reduced uptake + increased uptake
30
Giant Cell Tumor
fusion of growth plate
extend from metaphysis to epiphysis of knee
Benign, osteolytic -- transform into sarcoma (no MTS -- quasi-malignant)
31
Giant cell tumor FDG
Doughnut sign
Regional hyperemia - - diffuse uptake
Extremely avid
32
Non-ossifying fibroma
cortical lesion of long bones
regress spontaneously
33
Non-ossifying fibroma Bone scan
normal (osteolytic)
Ringlike pattern around photopenic lesion
Calcification -- uptake
34
Myositis ossificans
secondary to contusion, trauma
high uptake on bone scan
35
MTS
Bone pain, path fracture, cord compression
↑ AlcPhos, hypercalcemia, bone marrow aplasia
Hematogenous spread -- not joints -- axial skeleton (prox humerus, femur)
36
Risk Prostate Ca bone MTS
PSA>10,
Gleason>8, locally advanced,
↑ AlcPhos,
bone pain
37
Lytic MTS
RCC, ATC, neuroblastoma, lung, MM, lymphoma
38
Hypertrophic pulmonary osteoarthropathy
Primary -- pachydermoperiostosis
Secondary -- lung ca (NSCLC), bronchiectasis, emphysema
tram line sign
39
MTS Bone scan
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
40
Superscan MTS
↓ uptake in soft tissue and nephron-urinary tract
long bones, skull, no kidneys
DD hyperpara
41
MTS Intensive uptake >6m
progression
42
Radio changes Bone scan
within weeks - inflammation
after months - fibrotic change and ↓BP
43
Postchemo Bone scan
↑ uptake in kidneys
44
Flare phenomenon
2w-3m -- good response -- ↑pain
2-6m --↑ sclerosis (max 4-8w)
4-6m after flare -- regress activity
45
Degeneration
Joint - destroy
Spine - intervertebral disk - lose height
Cartilage - thin joint space
Osteophyte - joint instability
Facet - L5-S1 bilateral
Spondylolystesis - anterior displacement of vertebra
46
Degeneration Bone scan
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
Metabolic Bone Disease
Osteoporosis
Osteomalacia
Hyperpara
Renal osteodystrophy
48
Osteoporosis Bone scan
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
Sacral insufficiency fracture
Honda sign
50
Osteomalacia
Bone scan
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
Bisphosphonate therapy
weaken bone -- possible fracture -- MDP
52
Rickets
bowed legs, costochondral swelling
53
Oncogenic osteomalacia
ass with mesenchymal tumor -- paraneoplastic sy -- detect first primary by FDG, DOTA, DOPA
54
Hyperpara
↑PTH -- loss of Ca from bone -- weaken bone -- hypercalcemia
55
Primary hyperpara
PTA -- MIBI
56
Secondary hyperapa
vit D def, CKD, low Ca -- hyperstimulation
57
Tertiary hyperpara
autonomous
58
Hyperpara ass with brown tumor
replacement of bone with hemorrhage and granulation tissue
MIBI, FDG
59
Hyperpara ass with metastatic calcification
uptake in soft tissue, lung, thyroid, stomach
fractures
60
Hyperpara Bone scan
skull (grenadier soldier), jaw, sternum (tie sign), shoulder, rosary beads sign, uptake in stomach
61
Renal osteodystrophy
Bone scan
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
Paget
Diff blast/clast activity towards bone resorption
↑ vascularization
Lytic, mixed, sclerotic phase
↑AlcPhos
Mono/polyostotic (malignant transformation <1% -- low FDG)
63
Paget X-ray
Bone deformation
Cortex thickening
Lytic lesions as “flame”
64
Paget Bone Scan + FDG
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
Fatigue fracture
abnormal load on normal bone
athlete or military
66
Female athlete triad
eating disorder, amenorrhea, osteoporosis
67
Insufficiency fracture
normal load on weaken bone
osteoporosis, RA, MBD, neuro, radio, THR, steroid, fluoride therapy, bisphosphonate
68
Athlete + lumbar back pain
spondylolysis
bilateral -- spondylolisthesis
69
Fracture bone scan
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
Stress fracture
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
Stress fracture X-ray
Linear sclerosis
72
Stress fracture Bone scan
3-phase scan -- 100% sensitive
Positive 2 weeks before X-ray
Tibia, metatarsal bones
Focal area of hyperactivity
Grade I-IV
73
Shin Splint
insertion tendopathy
Abnormal movement of muscles
continue exercise while comfortable
74
Shin splint Bone scan
Linear or patchy uptake
Posterior tibial cortex
Vascular and BP normal
Important lateral views
75
AVN
Aseptic necrosis -- several days after insult -- reparation -- cold-in-hot spot
Bone infarct: alco, sickle cell anemia, radio, cytotoxic, steroids
76
Hip AVN
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
Osteochondrosis dissecans
bone fragmentation of joint end
78
AVN Bone Scan
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
AVN MRI
Most sensitive and specific for osteonecrosis
DD transient osteoporosis vs subchondral insufficiency fracture
80
Sympathetic reflex dystrophy
Bone scan
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
RA
Autoimmune inflammatory polyarthritis
Articular deformity
Small joints in hand and feet symmetrical
82
RA US
Early-stage arthrosynovitis, tendosynovitis
83
RA Bone scan
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
Seronegative Spondyloarthropathy
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
Seronegative Spondyloarthropathy spine
syndesmophytes (vertical osteophytes)
86
Seronegative Spondyloarthropathy Bone Scan
3-phase scan:
level of enthesis -- early diagnosis of sacroiliitis
Spondyloarthritis -- sternal, costotransverse, sacroiliac bones
87
Seronegative Spondyloarthropathy MRI
Preferred -- morphological evidence of degeneration
88
Osteomyelitis
Maxilla, mandible, long bones, spine -- ↑ blood supply
89
Osteomyelitis X-ray
Normal 2-4w
Later – cortical erosion, bone destruction, gas in soft tissue
90
OM Bone Scan
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
OM MRI
dd necrotic tissue -- detect presence of air, gas bubbles -- septic involvement of joint space, joint effusion and synovial thickening
92
OM Tc-HMPAO WBC
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
OM Radiolabeled anti-granulocyte monoclonal antibody
bone marrow accumulation higher than in vitro labeled WBC
imaging of chronic OM
94
OM FDG
Equivocal WBC -- FDG
Esp if neutropenia
>MRI in spondylitis
>Ga in paraspinal soft tissue infection
>bone scan in DD advanced arthritis vs infection
95
Spondylodiscitis
2 vertebra+disc
Staph aureus
96
Spondylodiscitis Bone scan
Low specificity 40%
Ga combi + MDP -- specificity 65-80%
Esp postop infection MDP>Ga -- degenerative
Ga>MDP -- vertebral infection
97
Spondylodiscitis MRI
Positive in first 2w
Gold standard for spine infection
Overestimation of extent -- unnecessary surgery
98
Spondylodiscitis FDG
Low specificity
Response to treatment -- score 0-4
DD infection vs neoplastic lesion or degenerative
99
Prosthetic joint implants
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
Prosthetic joint implants X-ray
Not affected by metal
Negative for 4 weeks
Later – radiolucent area around -- loosening
101
Prosthetic joint implants Bone Scan
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
Prosthetic joint implants Tc-HMPAO-WBC
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
