Musculoskleletal Imaging: Intro and General bone Flashcards
Bone is living tissue
it is dynamic
knowledge of the physiology and histology is essential to understanding radiographic changes associated with disease process
Interpretation paradigm
- Soft tissue changes
- Osseous changes
- periosteum
- Cortex
- Medulla
- Zone and rate
- Classify lesion as Benign or aggressive
- Differentials
Approach to interpretation
Signalment
patient age
Body condition and conformation
breed
previous injurties or surgeries
Approach to interpretation:
Comparison
Radiograph opposite limb for comparison
Soft tissue
- Evaluate visualization of Fascial Planes and margination of muscle groups
- Edema, hemorrhage, inflammation of tumor infiltration will result in loss of visualization of fascial planes
- Gaw, swelling or mineralization of soft tissue will cause changes in opacity
Opacity Changes:
Decreased
of soft tissue due to gass present in the soft tissue
Opacity Changes:
Increased opacity
of soft tissue due to increased soft tissue density, mineralization or foreign material ballistics
Opacity Changes:
Gas in soft tissues
areas of decreased opacity within soft tissues
Emphysema
Due to:
open would
Gas producing organisms
Latrogenic (post-operatively or following needle puncture)
Soft Tissue:
Mineralization
Increased mineral opacity within the soft tissue
Common causes:
metastatic mineralization
Dystrophic mineralization
Metastatic mineralization
Mineralization of normal tissue due to elevated serum calcium and/or phosphorus levels
Dystrophic Mineralization
Mineralization of dead, degeneratie, or devitalized tissue
metal opacity
ballistics
Iatrogenic (surgical)
Evaluating Bony Lesions
- Proximal to distal
- Outside to inside
- soft tissue
- periosteum
- cortex
- Edosteum
- Medullary canal
- Include joint above and joint below
Lesion Distribution
monostotic
polyostotic
Focal
generalized
symmetrical
asymmetrical
Predilection sites
Osteosclerosis
Radiographic term fro increased bone opacity
Rare in veterinry medicine
Usually artifactual or due to superimpostion
Osteopenia
Radiographic term for decreased bone opacity
Osteopenia:
Osteoporosis
Loss of bone mass
Quantity of bone decreased
Existent bone is of normal composition
Osteopenia:
Osteomalacia
Loss of mineralization of bone matrix
Quality of bone is decreased
Increased percentage of non-calcified osteoid and/or insufficient mineralization of osteoid matrix
Generalized bone lesions:
Causes of generalized osteopenia
metabolic disease
Nutritional disease
Disuse
Congenital disease - osteogenesis imperfecta
osteopenia
Wolff’s Law
Bone grows and remodels it responds to forces or demands placed on it
Evaluating Bony Lesions
- Bone response to injury and disease
- new bone formation, resorption or lysis or combination
- May require biopsy for diagnosis
- Radiographs used to determine lesion significance
- aggressiveness, activity, duration
- Radiographic changes lag behind clinical abnormalitites
- Lytic changes: may take 5-7 days to be visible radiographically
- Productive/Blastic changes: may take 10-14 days to be visible radiographically
Evaluating Bony Lesions:
Non-aggressive vs. Aggressive
- Location and number of lesions
- Pattern of lysis
- Pattern of new bone production
- Cortical changes
- Transition zone to normal bone
- Change in lesion appearance over time
Rate of Change
Radiographic appearance of an aggressive lesion will change rapidly relative to a non-aggressive lesion
radiographs obtained 10-14 days after initial fils may show a change in appearance of the lesion if it is aggressive
Non-aggressive lesions will appear the same due to the slower rate of change
Response of Bone to injury”
Osteoblastic Change
periosteal reactions
Callus
Osteophytes and enthesophytes
Response of bone to injury:
Ostelystic Change
geographic
moth eaten
permeative
Periosteal Reactions
- Is not unique to the disease process
- Anything that causes the periosteum to be elevated or stripped from the bone will results in a periosteal reaction
- Appearance of the periosteal reaction is rather an indication of the speed of the disease process and therefore the affressiveness of the pathology present
- Classification of aggressiveness is based on organization of new bone
- More disorganized the new bone formation → the more aggressive the lesion
Solid periosteal reaction
bone completely fills the area under the reaction
More chronic, the more solid/mineralized
The surface can be smooth or undulating
Usually non-aggressive
Callus
Lamellated Periosteal Reaction
Layered or “onion skin” appearance
Indicates a cyclic or intermittent process
More aggressive than solid, smooth new bone but usually associated with benign process
Spiculated periosteal reaction
- Periosteal reaction perpendicular to the cortex - along the sharpey’s fibers
- Can appear like Columns of bone
- Columnar seen with diseases like hypertrophic osteopathy
- Often seen with aggressive disease
Amorphous periosteal reaction
- Bone is formed in a disorganized manner
- Mineralization of the soft tissue adjacent to the bone pathology
- Process may destroy or displace spicules of bone as they are being formed
- Most aggressive reaction
- Most often neoplasitc in origin
Geographic Lysis
- Large area of lysis
- Lesion may appear expansile
- Well-defined with short zone of transition
- Nonaggressive or aggresive; however, usually considered least aggressive from of lysis
- Bone cysts, multiple myeloma
- Sclerotic margin +/-
Moth-eaten lysis
- Multiple smaller areas of lysis
- These areas may become confluent to form a larger area of lysis
- Usually indistinct margins
- Usually aggressive
- osteomyelitis, or neoplasia
permeative lysis
numerous small or pinpoint areas of lysis
Margins are indistinct
As permeative lysis progresses, the areas amalgamate to look moth eaten
Most aggressive patterns
usually associated with neoplasia
