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skeleton 2 (imaging mobility (Conventional radiography (Plain Film/X-Ray),…
skeleton 2
imaging mobility
Conventional radiography, US, CT, MRI, Radionuclide imaging (scyntygraphy), Arthography, Angiograhpy, PET
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US
- advantages: uses non ionising energy, non-invasive, quick, cheap, cross section in multi plans, Doppler sonography increases sensitivity of vascular structures, mainly for soft tissues, also joints in neonate and infants and soft tissues of joints in adults, biopsy guide.
- Disadvantages: inability to penetrate bone and deep tissues.
CT
- Advantages: short time, allows cross sectional with multiplanar and 3D, good resolution and detailed info. about bony cortex , trabecular patterns and calcifications, extent of lesion, thin-section imaging (1mm to 10mm), visualisation of adjacent soft tissue and organs, detection of occult (hidden) fractures,not affected by plaster casts.
- Dis:ionizing radiation, when planning for CT must have a clear idea of the clinical question to be answered, multiplanar capabilities and contrast resolution are limited in comparison with MRI, low quality images due to artefacts from metal appliances, contrast medium used to improve contrast resolution
MRI
- advantages: non-invasive, high contrast resolution, good for bones, joints, related ligaments and tendons, muscular attachment and cartilages, provides info. about bone marrow (red-fatty), essential in tumor staging, extent of lesion and defines its relationships to adjacent structures.
- Dis: expensive , time consuming, contraindicated in some pat., lack of signal from cortical bone and calcifications, artefacts from metal and motion - low quality images
Radionuclide imaging
- extremely sensitive and inexpensive imaging of entire skeleton.
- most common use:
detection of metastatic disease, bone marrow infiltration
detection of osteomyelitis, detection of occult (hidden) fractures
detection of avascular necrosis
- dis:
poor specificity- arthritis, degenerative changes, old fracture
low spatial resolution
whole body radiation with increased exposure to the pelvis
Arthography
- injecting contrast medium into joint space followed by X-Ray, CT or MRI
- useful in difficult cases, when non-invasive tech. are not effective.
- main indications: assessment of labrum in the shoulder and hip, triangular cartilage in wrist
- dis: invasive.
Angiograhpy
- invasive.
- rarely used after CT and MRI.
- indications: vascular integrity after trauma, tumor vascularity
Metabolic disorders
Osteoprosis
- the bone mineral density is reduced and bone microarchitecture is disrupted.
- Imbalance beetwen the bone resorption and bone formation
- general or local process
mechanism
- inadequate bone formation( Cushing’s disease, immobilization)
- excesive bone resorption (hyperparathyroidysm)
- inadequate new bone mineralization (deficiency of calcium and vitamine D)
generalised
- senile and postmenopausal
- endocrine disorders:
a. hyperparathyroidism b. Cushing’s disease c. hyperthyroidism
- alcoholism and tabacco smoking
- malnutrition and malabsorption syndromes
local
- specyfic and nonspecyfic inflamation
- postraumatic imobilization
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Bone mineral densimetry
DEXA
- Dual energy X-ray absorptiometry.
- it uses two different X-ray beams to estimate bone density in spine (lumbar) and hip
- strong, dense bones allow less of the X- ray beam to pass through them
- the amounts of each X-ray beam that are blocked by bone is compared to each other
- it uses very low doses of radiation
- other methods: US, quantitive CT
- test measures the density of minerals such as calcium in bones using a special X-ray computed tomography
- T-score: normal BMD > -1.0 SD, osteopenia (subabnormal)= -1 to -2.5SD, osteoporosis - low bone mass = < -2.55
Osteosclerosis
- abnormal increase in bone density due to replacement of cancellous bone by compact bone detected on a X-ray as an area of witheness
- reduction in bone mineral density; normal amount of bone, but reduced mineralization of normal osteoid
- diffuse, local
- diffuse: osteomielosclerosis, marble bone disease (osteopetrosis)
- focal: skeletal metastases, osteosarcoma, Paget’s disease, degenerative process, hyperostosis frontalis interna, specyfic and nonspecyfic bone inflamation, lymphoma
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Osteolysis
- destruction of bone, especially by active bone resorption or dissolution of bone tissue
- osteolysis predominantly occur in neoplastic and infectious disease
- also present in metabolic, traumatic and vascular disease
- the site of erosion can be: cortical bone erosion, intramedullary bone erosion
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- multiple osteolytic leasions presence in myeloma multiplex
predominantly affects: vertebrae column, sternum, skull, pelvis
radiological appearance: well-defined, sharp bordered foci of bone lucency
Solitary bone cyst
- predominantly in children
- clinicaly silent (occures as a pathological fracture)
- 50% localise affects proximal part of the humerus
- X-ray appearance: central, well-defined area of bone destruction with associated some bone expansion
Periosteal reaction
formation of the new bone in response to injury, chronic irritation, bone healing, subperiosteal hematomas, osteomyelitis and cancer of the bone
- Different morphologies of the periosteal reaction:
single layer of the new bone in benign or malignant tumors, **infection and secondary hypertropic osteoarthropathy
multiple layers (lamellated) - „ onion skinning” may be seen in hypertropic osteoarthropathy, osteomyelitis, tumors
linear spicules – Ewing’s sarcoma**
linear spiculaes in radial configuration ( perpendicular) - „ sunburst” osteosarcoma
linear new bone in a triangular configuration – „ Codman’s triangle suggestive of malignancy
Arthritis
- Radiographic Hallmarks of Osteoarthritis:
joint space narrowing – typically non-uniform
subchondral sclerosis
subchondral cyst formation
osteophytes
- Radiographic Hallmarks of Rheumatoid Arthritis:
joint space narrowing – typically uniform
soft tissue swelling
erosions
periarticular osteopenia
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- pathological signs of bone disease:
osteopenia/osteoporosis: bony atrophy
osteolysis: bone destruction ( loss of trabecular)
osteosclerosis: abnormal high bone density
periosteal reactions
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