Upload
randolph-webster
View
226
Download
0
Tags:
Embed Size (px)
Citation preview
THE SKELETAL SYSTEM
MUDr.Kateřina Táborská
Bone scintigraphy
Bone physiology and skeletal anatomy
balance osteogenesis bone resorption osteoblasts osteoclasts
The response of bone to injury or disease ↓
reactive bone formation
Radiopharmaceuticals:
99mTc – diphosphonates ( MDP –methylene diphosphonate)
Concentration predominantly in the mineral phase of bone (crystalline hydroxyapatite and amorphous calcium phosphate) iv.distributed via blood flow throughout the bodypassively diffused into the extravascular and extracelular spacesbinding to the hydration shell around the bone crystalunbound radiotracer clears from the plasma via urinary excretion
Uptake of RF depends on:
1. blood flow
flow must be present for delivery
increased blood flow increased deposition
2. metabolic bone activity
bony turnover
osteoblastic lesions growth centers
Patient preparation:
good hydration
to urinate immediately prior imaging
Contraindiaction:
pregnancy
Two types of bone scans:
Standart bone scan:
iv., imaging of the entire skeleton, 2-5 h
Three-phase bone scan:
1. Phase – angiographic
rapid sequence flow images of the area of interest (60 x 1 sec.)2. Phase (blood pool, soft tissue uptake)
ten minut delayed static images3. Phase (bone)
delayed images of the region in question, 2-5 h
3F bone scan
whole body bone scintigraphy
Bone SPECT
Bone SPECT – improved sensitivity greater anatomic details
3D rekonstrukce sagitální
koronální
transaxiální
I. 3D rekonstrukce II. tomographic slices
Static images
Static images with pinhole collimator
ANT
pinhole
Normal scan: axial and appendicular skeleton
Symetry, the bones with minimal soft-tissue activity
Both kidneys with mild activity, urinary bladder
Normal scan: children
increased uptake in growth centers
margins of growth plate clearly demarcated
Areas :increased uptake 95 - 98% (fracture, osteomyelitis, neoplasia, arthritis)decreased uptake (lytic lesions, early necrosis)
Abnormal scan
Abnormal scansuperscan
Diffuse symetrical increased uptakeLack of kidney activity
Soft tissue or extra-osseous uptake
inflammation, calcification, muscle or tumor necrosis, myositis
neuroblastoma rhabdomyolysis
hydronephrosis
hydroureter
excretion via genitourinary tract
nefrocalcinosis
INDICATIONS
1. metastatic disease
2. primary malignant bone tumors
3. benign primary tumors
4. osteomyelitis
5. fracture
6. avascular necrosis
7. metabolic bone disease
METASTATIC DISEASE
Tumors most likely to metastasize to bone:
breast
prostate
lung
lymphoma
thyroid
renal
neuroblastoma
METASTATIC DISEASE
more sensitive than plain RTG, 30-50% of bone mineral must be lost before a lesion can be detected
surveying of the entire skeleton
Approximately 90% of metastases are multiple
initial staging
follow up
diffuse bone pain
laboratory findings (PSA)
Prostate cancer
METASTATIC DISEASE
flare fenomen
3-6 mo after chemotherapy, hormonal therapy
increased uptake in known lesions and even new foci may be seen because of a healing response
serial scanning
PRIMARY MALIGNANT BONE TUMORS
Osteosarcoma
Ewing‘s sarcoma
3F bone scan
WB - skip lesions and metastatic foci
Osteosarcoma
19-year old man with pain of right knee, the initial staging
Ewing‘s sarcoma
17-year old man with pain of left knee, the initial staging
Osteosarcoma of left tibiaPersistent increased uptake at the treatment site 6-12 mo after therapy, compared with a postherapy baseline, is considered suspicious for local recurrence
21-year old man after chemotherapy and amputation
usually normal uptake bone cysts bone islands fibrous cortical defects
osteiod osteoma negative scan virtually rules out
BENIGN PRIMARY TUMORS
16-years old girl with aching pain, worse at night, relieved with aspirin and exercise at right
OSTEOMYELITIS
3-phase bone scintigraphy
flow – increased
blood pool – increased
delayed – increased
dif.dg. cellulitis – increased only flow and blood pool
high sensitive on unaffected bones
positive during 24-48 h
X-rays normal for first 10-14 days
1.phase 2.phase 3.phase
Osteomyelitis (left calcaneous)1.phase (curve from the region of interest - ROI)
multifocal osteomyelitis
13-year old girl with OM of left clavicule
6-year old boy with pain of left thigh
1.phase 2.phase 3.phase
1.phase
Myofasciitis of left thigh
FRACTURE
TRAUMATICwill become positive within 24 h 90% normal by 2 yearstu pick up old fractures such as in spinechild abuse
STRESS a) fatigue – caused by repeated abnormal stress on normal bone - runnersb) insufficiency – resulting from normal stress on abnormal bone (osteoporosis, postirradiation)
polytrauma
27-year old woman after car crash
13-year old boy after fall from tree
Fracture of Th 8
Stress fracture of left tibia
17-year old girl with painful left leg after training for an athletic event
ANT anterior lateral
pinhole collimator
AVASCULAR NECROSIS
Adults – as a result of fracture, metabolic disorder, steroids, hemolytic anemias, vasculitis
Children: Legg-Calve- Perthes disease
early: decreased activity
followed by increasing activity if subsequent revascularisation and healing occur
Morbus Perthes l. sin.
normal early phase
5-year old boy with hip pain
METABOLIC BONE DISEASE
OSTEOPOROSISOSTEOMALACIAHYPERPARATHYROIDISM (primary, secondary)
superscan or complication: pseudofracture,compresive fracture
PAGET‘S DISEASEincreased resorption of bone accompanied by increase in bone formationnewly formed bone is abnormally soft increased uptake due to significant increase in blood flow
PAGET‘S DISEASE
ADVANTAGES
high sensitivity
early changes
ability to survey the entire skeleton without added radiation (5 mSv)
DISADVANTAGES
lack of specificity
A specific diagnosis often can be made when the bone scan is correlated with other imaging
(plain films, CT)