Diagnostic Imaging Flashcards
(281 cards)
1
Q
5 radio opacities
A
Air
Fat
Fluid (soft tissue)
Mineral (bone)
Metal
2
Q
What colour is radio opaque
A
White
3
Q
What happens to a structure furhter away from the imaging plate?
A
It is magnified
Structures closer to cassette appear smaller than those further away (like a hand in a shadow)
4
Q
What colour is positive and negative summation?
A
Positive -> white, two soft tissue opacities = thicker and more opaque
Negative -> two gas opacities become darker
5
Q
What is border effacement? **
A
AKA negative silhouette sign
Two structures with same opacity next to each other result in loss of border
Eg right middle lung lobe with soft tissue opacity due to fluid or abscess effacing border of the heart
6
Q
What is border enhancement?
A
AKA positive silhouette sign
Silhouette of adjacent objects of the same opacity is enhanced when surrounded by a different tissue opacity (eg in a pneumothorax the heart looks more defined)
7
Q
What is PLACE used for?
A
To assess quality
- Positioning
- Labelling
- Artifacts
- Collimation and centering
- Exposure
8
Q
7 descriptive factors to describe abnormalities: (roentgen signs)
A
Size
Shape
Location/position
Margination
Number
Opacity
Function
SSLMNOF
9
Q
What is a radiological diagnosis?
A
Diagnosis that can be made from 1 radiograph alone with no other info
10
Q
What are the 7 possibilities for differential diagnosis?
A
DAMNITV
Degenerative
Anomalous/acquired
Metabolic
Neoplastic
Infectious, inflammatory, immune
Traumatic
Vascular
11
Q
Steps to write a rad report
A
- Identify case - name, species, maturity
- Identify all views taken
- Evaluate radiographic quality
- Describe all radiographic abnormalites
- Conclusion (list radiologic diagnosis, list prioritised differential diagnosis)
- Consider further imaging procedures that would be of value
12
Q
What is a bias error?
A
Expecting to find something
13
Q
What is a searching error?
A
Not being systematic and thorough
Over reliance on pattern recognition
14
Q
What is a recognition error?
A
Abnormalities recognised but given too much weight or not taken into account causing a misinterpretation of results
Over or under reading
15
Q
What is a decision making error?
A
Which abnormalities are assumed to be important
16
Q
What is an egocentric error?
A
Overestimating your personal grasp of the truth
17
Q
How many orthogonal views should be taken?
A
Minimum of 2
eg ML and CrCd
18
Q
What should radiographs of long bones include?
A
Proximal and distal adjacent joints
19
Q
What should views of joints include?
A
1/3 of bone above and below
20
Q
What is the epiphysis?
A
Top or end of the bone
21
Q
What is the metaphysis?
A
Just below epiphysis
22
Q
What is the diaphysis?
A
Whole central part of bone
23
Q
What is the physis?
A
growth plate - primary centre for ossification
24
Q
What is the apophysis?
A
Part of bone with physis, but unlike epiphysis does not have a joint
25
What is the periosteum?
Membrane covering the outside of the bone
26
Endosteum
Membrane on the inner part of the bone
27
Trabeculae
Small fine lines on the ends of bones
28
What is intramembraneous ossification?
Ossification in fibrous tissue -> flat bones, skull and most facial bones
Mesenchymal tissue replaced by bone
Ossifies in embryo -> diaphysis then epiphysis
Periosteum produces bone by intramembranous ossification
Grow in length on the metaphysial side
29
What is endocondral ossification?
Ossification of preformed cartilage frame (cartilage replaced by bone)
Typical long bone has 3 centres of ossification
1. Diaphysis (primary centre)
2. Epiphysis (secondary ossification centres)
30
What side of the physis do we see increased bone opacity?
Metaphyseal side
31
Primary centre of ossification
Diaphysis - growing and lengthening
32
Secondary centres of ossification
Epiphysis -> bone length
Apophysis -> bone shape
Small bones -> carpi, tarsi
33
Accessory centres of ossification
Sesamoid bones
Focal areas of mineralisation near joints
34
What are sesamoid bones? What do they lack?
Small smooth rounded structures formed where tendons pass over a joint to reduce friction, protect and stabilse a tendon
Usually one one surface is articular
Lacks a periosteum
35
Where are accessory ossification centres (ossicles) normally found?
Many locations usually near joints or embedded in joint capsule
Generally represent normal variants that need to be differentiated from pathology
36
Examples of an accessory ossification centre
Accessory caudal glenoid ossification centre -> Found in medium-large breed dogs and failure to unite can cause pain
Clavicles -> ossified in 96% large dogs and all cats
Pelvis -> acetabular rim craniodorsal margin may not fuse completely
Os penis -> usually 1 but can develop 2+ centres
Coronoid process - incomplete ossification associated with elbow dysplasia
37
2 normal radiographic features of bone
Nutrient foraminae -> in all long bones, location of major blood vessels and nerves supplying medulla
Mach lines -> 2 cortical surfaces are superimposed causing optical illusion of a radiolucent line
38
2 types of joints
Synarthroses - not synovial (immovable joints like teeth to mandible)
Diarthrosis - synovial (freely moveable like elbow, ankle, knee)
39
4 Standard projections for joints
1. Craniocaudal
2. Caudocranial
3. Mediolateral
4. CrMCdLO (craniomedial caudolateral oblique or CrLCdMO
Flexed or extended, with traction or torsion
40
What is stress radiography for joints?
Applying force like compression, rotation, traction, shear and wedge
41
What is 5 alternative imaging for joints?
Arthrography
Ultrasound
MRI
Contrast athrography - inject contrast medium to see cartilage joint (invasive hole in joint)
Computed tomography
42
What does increased opacity indicate?
Productive or sclerotic changes
43
What does decreased opacity indicate?
Osteolysis or osteoporosis
44
5 ways bones react to disease
1. Increased opacity
2. Decreased opacity
3. Periosteal reaction (new bone)
4. Change in size or contour
5. Change in trabecular pattern
45
What is Wolff's law?
Bone responds to stresses placed on bone -> osteoblast and clast activity
Remodelling
- Periosteal, cortical, subchondral, endosteal and cancellous
| Endosteum -> lines medulla inside bone
Periosteum -> Lines outside
46
ABCDS for musculoskeletal evaluation
Alignment
Bones
Cartilage
Devices
Soft tissue
47
ABCDS -> alignment
Describe distal part relative to proximal part
eg Lateral displacment of antebrachium relative to the humerus
| Antibrachium - region from wrist to elbow
48
ABCDS -> bone
Response of bone is limited to:
Response of bone is limited to:
1. Increased radio-opacity -> Sclerosis - increased density of bone OR apparent sclerosis (superimposition of bones)
2. Decreased radio-opacity -> seen after 7-10d. Osteomalacia (poor quality good quantity), osteopaenia (good quality, poor quantity) or osteolysis (abnormal focal area of bone resorption)
49
4 Roentgen signs of osteopaenia
Reduced bone opacity
Cortical thinning
Coarse trabeculae
Loss of lamina dura around teeth
| good quality, bad quantity of bone
50
In a diseased bone what is the usual response with decreased radio opacity?
Combination of lysis and sclerosis
51
Aggressiveness of bone lesion determined by looking at:
Location and distribution
Presence of cortical disruption
Pattern of lysis and production
Type of periosteal reaction
Rate of change of lesion
Zone of transition
52
4 Factors involved in assessing location of lesion
General or diffuse -> metabolic or nutritional
Whole limb -> disuse atrophy or neuropathy
Focal or multifocal
Symmetrical
53
Monostotic vs polystotic lesions
Monostotic -> primary bone tumours occur principally in the metaphyseal area. Can be cancerous or not cancerous
Polostotic -> metastatic tumours often more than one bone involved usually within diaphysis. Spread from elsewhere to bone
54
Signs of cortical involvement
1. Thickened cortex
2. Thinned cortex
3. Broken cortex
If no cortical involvment -> likely benign
Look at both endosteal surfaces and periosteal
55
3 bone lysis patterns from least to most aggressive
1. Geographic
2. Moth eaten
3. Permeative
56
Describe geographic lysis
Uniformly destroyed with defined border
Well demarcated, cortex expanded but not lytic
Often benign
57
Describe moth eaten lysis and 3 things it could be caused by
Ragged borders, multiple areas of lysis 3-10mm in size
Cortex irregularly eroded
Bone tumours, multiple myeloma and osteomyelitis
58
Describe permeative lysis
ill defined and spreading through marrow space
multiple pinpoint areas of lysis, cortex irregularly eroded
most agressive
Most likely bone tumour
59
Name 6 continuous periosteal reactions
Smooth and solid
Codmans triangle
Rough and solid
Lamellar
Brush border
Pallisading
60
Name 3 interrupted periosteal reactions
Spicular
Sunburst
Amorphous
61
Causes of lamellar periosteal reaction
Single layer of new bone
Onion skin -> trauma, infection
62
Which type of periosteal reaction is associated with malignancy?
Amorphous periosteal reaction
Random deposition of new bone in soft tissue adjacent to lesions
63
What is codmans triangle?
Occur when bone lesions are so aggressive the periosteum is lifted off the bone
Triangular cuff at edge of aggressive lesion formed due to periosteal elevation
Caused by anything that lifts periosteum off the cortex both benign and aggressive - haematoma or fracture
Not pathognomonic for a tumour
64
How long do destructive and productive changes take to be seen on radiograph?
Destructive -> 5-7d to be seen
Productive -> 10-14d to be seen
65
What is a transition zone and what does it mean if it is abrupt or indistinct?
Appearance of region between lesions and adjacent normal bone
Short and abrupt -> benign
Indistinct -> aggressive
66
4 Features of benign lesions
1. Well defined border
2. Lack of soft tissue mass
3. Solid periosteal reaction
4. Geographic bone destruction
67
4 features of malignant lesions
1. Interrupted periosteal reaction
2. Moth eaten or permeative destruction
3. Soft tissue mass
4. Wide zone of transition
68
What density is cartilage?
Soft tissue density -> cannot see it on radiographs clearly
69
How do we assess cartilage on radiographs?
Soft tissue changes -> opacity changes, swellings, atrophy
Subchondral bone destruction or sclerosis
Narrowing of joint spaces, intra-articular fractures
70
3 causes of gas opacity changes
1. Laceration
2. Gas producing organism
3. Iatrogenic
71
3 causes of mineralisation
1. Dystrophic
2. Metastatic
3. Neoplastic
72
3 causes of opacity changes
1. Gas
2. Mineralisation
3. Foreign material
73
2 causes of enlargments in soft tissue
1. Intracapsular soft tissue swelling -> centred on a joint, soft tissue opacity effusion
2. Extracapsular soft tissue swelling -> away from joint or extends beyond joint, may obscure intra-capsular swelling
74
What are 2 tell tale aggressive locations?
Metaphyseal (primary bone tumour)
Diaphyseal (metastatic bone tumours)
75
What does it suggest if the cortex is broken?
Aggression
76
What would the zone of transition be like in an aggressive lesion?
Indistinct, permeative, long zone of transition
77
What would the zone of transition be like in a non-aggressive lesion?
Sharp, distinctive short zone of transition
78
4 periosteal reactions suggesting an aggressive lesion
Indistinct, permeative, spiculated, amorphous
79
Periosteal reaction suggesting a non-aggressive lesion
Smooth continuous
80
4 bones in the carpus
Radiocarpal bone
Intermediate
Ulnar
Accessory
81
What is horizontal beam radiography used for?
To see gas or fluid in the peritoneum
If the animal is in pain to keep them still
82
What is stress radiography good for?
Aids in joint laxity
Limb is stabilised above and below join or other area of interest
Force is applied to joint and instability shown
83
Standard views of the scapula
Le to Rt Lateral
CdCr
May need two laterals: body and neck of scapula
84
Shoulder joint / scapula neck standard views
ML
CdCr
Optional: Flexed ML, CrCd or skyline (CrPrCrDiO)
85
3 ligaments attaching to shoulder joint
Biceps brachii tendon
Transverse humeral ligament (medial)
Glenohumeral ligaments (medial and lateral)
86
What is a skyline image?
CrPrCrDiO
87
Standard views of the humerus
ML
CdCr
Include proximal and distal joints in
88
Standard views of the elbow
ML
Flexed ML
CrCd
89
Special views of the elbow
Cr15degreesL - CdMO for a fragmented medial coronoid process and shows medial humeral condyle
Cr15degreesM-CdLO for incomplete ossification humeral condyle fissures
90
Elbow ligaments
Lateral and medial collateral ligaments
Annular ligament of radius
Flexor carpi ulnaris
91
Cr15degreesL-CdMO view of elbow benefit
Improve visibility of medial coronoid process and medial humeral condyle
92
Standard views of the carpus
DPa
ML
93
Special views of the carpus
Flexed ML
Stressed extended
Obliques
94
Manus standard views
Dpa
ML
Any oblique view to highlight specific digits and sesamoids
95
Special views of the manus
Stressed digit -> use porous tape or cotton wool to splay digits on ML view
Compression
96
Pelvis standard views
Laterolateral
Extended VD
Optional flexed frog leg VD
97
Pelvis special views
any oblique to highlight specific area
98
Hip dysplasia views
Extended VD
Penn hip
99
View of pelvis if one side positioned in front of the other
Right cranial left caudal oblique
(left would be in front (cranial) here)
100
Important factors in VD extended coxofemoral view (hips)
Entire pelvis in including proximal tibia
Must be symmetric = femurs parallel and patellae in middle of stifle (legs turned slightly in so patella superimposed over distal femur)
Animal in dorsal recumbency, collimation includes lasat 2 lumbar vertebrae and patellas
101
3 ligaments in sacroiliac joint
Dorsal sacroiliac ligament
Ventral sacroiliac ligament
Sacrotuberous ligament
102
Hip joint features
Joint capsule
Ligament of head of femur
Transverse acetabular ligament
103
VD flexed frog leg process and reason
Good for fractures and can see degree of subluxation in hip dysplasia
Dorsal recumbency
Pelvic limbs flexed
Collimation includes last 2 lumbar vertebrae, proximal femurs and tuber ischii
104
Penn hip method
1. Obtains OA readings from standard hip extended view
2. Obtains hip joint congruity readings from compressed view
3. Obtains quantitative measurements of hip joint laxity from distraction view
Accurate in puppies as young as 16wks
105
What DI rating is unlikely to develop OA from hip dysplasia (penn hip)
DI <0.3 (femoral head comes out of joint by <30%) is unlikely to develop OA from hip dysplasia
106
Femur standard views
ML
CrCd
107
Stifle standard views
ML
CdCr or CrCd
Flexed ML
108
5 ligaments of the stifle joint
1. Medial femoropatellar ligament
2. Tendon of quad femoris
3. Patellar ligament
4. Medial collateral ligament
5. Region of menisci (cranial and caudal cruciate ligament)
109
Skyline of patella view and its use
CrPrCrDiO
Used to better visualise patella and trochlear groove
Used in cases of medial or lateral luxating patella
Often in horses for sagittal fracture of patella
110
Standard views tarsus
ML
PlD
DPl
111
Special views tarsus
Flexed ML
Extended ML
Relevant obliques for pathology
Flexed DPl view (skyline)
112
For a horse with OCD what view of the tarsus is done?
Flexed ML
113
PlD view tarsus
Sternal recumbency
leg stretched out behind caudally
Easier to extend if dog has hip disease
Rotate stifle internally
114
Pes (hind paw) views
ML
DP
Splayed
same as front toes
115
5 causes of fractures
Trauma from external force
Trauma from internal force
Normal activity on diseased bone
Stress protection/stress riser -> weakened bone at end of plate
Defect in bone due to biopsy or surgery
116
3 Reasons for missing a fracture
Incorrect exposure, positioning, not enough views
Non displaced fragments -> if hairline fracture suspected but not seen re-evaluate in 7-10d
Confusion with physees and other mimics
117
What views should be taken to assess fractures
Several orthogonal views, obliques and stress views
118
5 normal causes of radiolucent lines
1. Nutrient foramen
2. Normal physes
3. Multipartite sesamoids/separate ossification centres
4. Mach lines (bone overlying bone)
5. Overlying fascial planes containing fat
119
9 steps in describing fractures
BTPDUJASP
Bone involvement
Type of fracture
Physeal involvement
Displacement, angulation
Underlying bone pathology
Joint involvement
Age of fracture
Soft tissue injuries + infection
Presence of foreign material
120
Fracture types - incomplete/complete
Open -> gas or foreign material in site, bone beyond skin margins, infection risk
Closed
Complete or incomplete -> does it involve both cortices?
Complete ->
simple - 1 fracture line, transverse, oblique, spiral OR
comminuted - 2 or more fracture lines, segmental (2 fracture lines isolating a segment) or butterfly fragments
Incomplete -> one cortex involved
Hairline -> thin fracture line, no disaplacement, full depth not involved
Greenstick -> cortex broken on convex side
Torus -> Cortex buckles on concave side
121
Rest of the fracture types
Avulsion - bony insertion of ligament/tendon involved (slab or chip fracture)
Compression - often no line seen, bones impact into each other
Fatigue or stress fracture - from repeat trauma
Shearing fracture - abrasion type open fracture
Condylar fractures - involve condyle and metaphysis
Monteggia fracture - luxation of radial head with proximal ulnar fractures most likely from trauma, with types 1-5 based on degree of luxation of radial head
122
Physeal growth plate fractures - how are they classed?
Occur only in immature animals
Classed according to degree of involvement of the epiphysis, physis and metaphysis
Salter Harris fracture types are correlated to chance growth deformity occurs when the fracture heals -> 1-5
1 is best prognosis 5 is worst
123
Salter Harris fracture classes
1 -> through growth plate
2 -> through growth plate and metaphysis
3 -> through growth plate and epiphysis
4 -> through all 3 elements
5 -> crush injury of the growth plate
124
3 other factors of fracture assessment
Joint involvement - articular fractures need stable fixation
Age of fracture - sharpness of bone edges
Presence of foreign material
125
2 types of fracture healing, and factors to assess progress
Primary and secondary
ABCDS -> alignment, bone, cartilage/joint, decide, soft tissue
Post op rads taken at 2,4,6 weeks then monthly until healed
126
Stages of secondary healing
5-10d
10-20d
>30d
>90d
127
Characteristics of day 5-10 of fracture healing
Fragments lose sharp edge
Demineralization
Fracture widens
128
Characteristics of day 10-20 of fracture healing
Endosteal and periosteal callus
Decrease size of fracture gap
Fragments lose opacity
129
Characteristics of day 30 of fracture healing
Fracture line disappearing
Callus bridges
Remodeling
130
Characteristics of day >90 of fracture healing
Callus remodeling
Cortex visible
Remodeling continuity of medullary cavity
131
3 features of fracture healing
Bone continuity of cortex
Calcified and ossified complete bridging callus
No visible fracture line
Usually healed 6-8wks later if adequately stabilised
132
Which type of healing is faster?
Secondary
133
Primary vs secondary healing times in 2yr old dog
Primary -> 5-12 months
Secondary -> 2-3 months
134
Secondary healing time in 4wk old puppy vs 1yr old dog
Pup -> 2-3 weeks
1yr old -> 8-12 weeks
135
What is disuse osteopaenia?
Effects of non weight bearing especially if a cast is applied
Cortical thinning
Double cortical line
Reduced bone opacity
Coarse trabecular pattern
136
What causes lysis adjacent to implants?
Loosening or infection
137
6 factors affecting fracture healing
Blood supply
Type of fracture
Reduction of fracture
Stability
Age of animal
Concurrent disease or infection
138
Radiographic signs of complications of fracture healing
No callus
Exuberant callus
Angulation or rotation of fragments
Lysis at fracture margin and separation of fragments
Zone of radiolucency around fixation devices within the bone
Failure of implants
Delayed union -> mostly due to instability
139
What is malunion?
Bone healing but in abnormal position
Valgus
Varus
140
Causes of infection in fracture healing
Open fracture
Contamination
Long surgical procedures
Excessive tissue damage
Foreign material
141
What can cause a fracture induced sarcoma?
A metal plate that has irritated bone and caused a reaction due to chronic movement
142
What is Metalosis ? What changes occur?
Chemolysis due to incompatible metals used for internal fixation which causes an osteolucent response around the implant resulting in loss of stability and implant failure.
Osteolytic changes appear similar in appearance to early osteomyelitis
143
What is implant (hardware) failure?
Metal fatigue causing fractures of plates, screws or pins that causes instability and fraction non-union 
144
What can happen to young animals with traumatic incidents to antebrachium?
The physis can close prematurely causing angular limb deformities where one bone stops growing and one continues and bends.
The distal ulna and radius are most commonly affected and it leads to joint incongruity
145
Structural changes that occur after premature distal ulna growth plate closure:
Shortened ulna
Cranial and medial bowing of radius
Valgus Deformity
Humerus forced proximally
Widening on humeral-ulnar joint
146
Structural changes during premature distal radius physis closure
Shortened radius
Widened humeral-radial joint space
147
2 categories of a primary bone neoplasia
Malignant -> solitary, aggressive, often metaphyseal
Benign -> less common, slow growing
148
Characteristics of secondary bone neoplasia
Metastatic
Haematogenous spread, multiple aggressive lesions,
Polyostotic distribution
Diaphyseal commonly (nutrient foramen located here)
149
Is osteosarcoma malignant or benign? Where does it start?
Malignant -> also 85% of bone tumours
Starts in metaphysis of long bone
150
Example of benign bone neoplasm
Osteoma - protruding cell mass with abnormally dense bone in the periosteum (skull and facial bones common)
151
4 types of primary bone neoplasia and their occurrence as a %
Osteosarcoma 85% (highly malignant)
Chondrosarcoma 5-10% (malignant -> benign, diverse cartilage tumours)
Fibrosarcoma <5% (produce fibrous tumour rather than bone)
Haemangiosarcoma <5%
152
Where are osteosarcoma common?
In juveniles in the distal femur
153
Where does multiple myeloma occur?
Most common polyostotic malignant primary bone tumour
Occurs in bone marrow
Often originates in diaphysis
154
Where does lymphoma of bone occur?
In reticular cells, lymphoblasts and lymphocytes of middle aged patients
155
Where do malignant giant cell tumours occur?
Rare
Extremities of long bones
156
3 things osteosarcoma could be associated with
What doesn’t it cross?
A fracture site months-years later
Internal fixation devices
Chronic osteomyelitis at the fracture site
The joint space
157
3 locations osteosarcomas occur
Proximal 1/3 of humerus, distal 1/3 of radius and ulna
Distal 1/3 of femur and proximal 1/3 of tibia
Proximal 1/3 of femur *rare* and distal 1/3 of tibia *rare*
158
Radiographic findings of osteosarcomas
Lots of lysis, monostotic, metaphyseal usually
Lysis is aggressive and involves cortex
Periosteal changes (sunburst, spiculated)
Soft tissue swelling or pathological fractures both may be present
Endosteal indentations resulting in cortical spike formations
Codmans triangle
159
Features of benign bone neoplasia
No age, breed or site predilection
Causes lameness only when pathological fracture occurs
Geographic lysis, short transition
160
3 types of benign bone neoplasia
Osteoma (face bump)
Osteochondroma - grows until phyis closes
Enchondroma - expanding medullary tumour
Bone cysts
161
Osteoma description
dense cortical bone with smooth periosteal reaction
162
Enchondroma description
Common benign intramedullary cartilaginous neoplasm
Trabeculae +/- radiolucent centre may be seen
Ddx - bone infarcts
Circles of new bone laid down, puts pressure on cortex
163
Features of bone cysts
Expansile fluid filled radiolucent lesions in diaphysis/metaphysis of long bone
Well demarcated transition zone
Cortical thinning - path fractures
164
Bone infarcts - where, what
Osteonecrosis in the metaphysis most commonly, can be diaphysis
Symmetrical or multiple infarcts
Shell like new bone formation and sclerosis with creeping, wavy margin
Discrete calcification and periostitis may also be seen
165
What is an osteochondroma and what is the new bony growth in an osteochondroma called?
Osteocartilagenous exostosis
Multiple osteochondromatosis (multiple tumours)
Osteochondroma -> most common benign tumour of bone, occurs where cartilage being converted to bone. Grow until physis closes
Can be of viral cause in cats
166
What is synovial osteochondromatosis?
Benign proliferative disease of the synovium with cartilage metaplasia, resulting in multiple intra-articular loose bodies
Ranges from synovial tissue to firm nodules of bone forming cartilage
Can occur idiopathic or secondary to osteoarthritis
| Metaplasia -> conversion of one tissue type to another
167
Common sites for metastatic bone neoplasia
Diaphysis or metaphyseal
Usually affects the diaphysis of long bone (but can be any bone)
Femur, humerus, vertebrae + ribs
168
Generally Where do metastatic bone neoplasia occur? What is their appearance?
Downstream from blood vessel of primary area it started (often starts in lungs)
Aggressive and may be lytic and/or proliferative, often in older animals with no breed specifically
Eg multiple myeloma
169
Example of a type of metastatic bone neoplasm
Multiple myeloma characteristically lytic with punched out appearance
Monoclonal gammopathy
Atypical plasma cell proliferation in bone marrow
Often vertebrae and ribs can be elsewhere
170
Primary site for metastatic squamous cell carcinoma
Tonsillar
171
Bone tumour and bone infection similarity
Both aggressive
172
What would a solitary, aggressive metaphyseal lesion be?
Primary bone tumour eg osteosarcoma
173
What are two things that happen with chronic infection in bone? (osteomyelitis)
Sequestrum -> increased mineral opacity
Involucrum -> irregular thickening of cortex of dead bone
174
Two types of osteomyelitis
Fungal or bacterial
Both infection of bone
175
What is bacterial osteomyelitis normally secondary to? and what symptoms are present?
an open wound - an extension from soft tissue injury, a puncture site, open fracture, surgical procedure
Osteomyelitis is inflammation of bone or marrow due to infection normally
Pain, fever, swelling, leukocytosis, fistulous tracts
176
Differences between bacterial osteomyelitis and bone tumours - location, periosteal reaction
Osteomyelitis -> typically not metaphyseal, can be anwhere, not as aggressive as a bone tumour, can involve more than one bone, most have pallisading periosteal reaction (not spiculated like tumours) and may have small gas opacities
177
What are the causes of bacterial osteomyelitis?
Occaisonally bacteraemia, haematogenous spread (usually in skeletally immature animals)
Bacterial endocarditis, neonatal umbilical infection
178
What are the lesions like of haematogenous bacterial osteomyelitis?
Lytic, productive or mixed - depends on virulence of organism and immune system of animal
179
Characteristics of fungal osteomyelitis - location, population it affects, origin
Mycotic
Geographic distributions
Young, large breed dogs (uncommon in cats)
Haematogenous in origin
Usually in metaphysis of long bones but can be diaphysis
Can cross joints - polyostotic
180
3 common fungal agents causing osteomyelitis in australia
1. Aspergillosis - immune compromised german shepherds
2. Actinomcyes - from grass seed migration to vertebrae
3. Cryptococcus
Can be confused with tumours - look for systemic illness and fever
181
2 types of protozoan bone infections and signs
Leishmanisasis
Hepatozoonosis (rare)
fever, weight loss, muscle atrophy, ocular discharge, pain
182
Radiographic lesions of protozoan infections
Limited to periosteum
Irregular profliferation or smooth
Polyostotic (multiple bones) aggressive lesions
183
Acute radiographic signs of osteomyelitis
First leions seen at 7d when lysis/periosteal reaction occurs - proliferative and moderate aggression - can extend down shaft of diaphysis
Lysis of cortical and medullary bone
Diffuse soft tissue swelling
184
Chronic radiographic signs of osteomyelitis
Sclerotic margin around lytic areas
Sequestrum formation
Periosteal proliferation may or may not be present
Soft tissue swelling
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6 differential diagnosis of osteomyelitis
Neoplasia
Bone cyst
Delayed fracture union as a result of instability
Hypertrophic osteodystrophy
Secondary hypertrophic osteodystrophy
Medullary bone infection
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2 types of subungal tumours
Squamous cell carcinomas - most common. Seen in large breed black dogs
Malignant melanomas
187
A type of subungal infection
Pododermatitis
188
Common factors between subungal infection and tumours
Both can occur in manus or pes at equal frequency
Both aggressive bone lesions with bone lysis
189
Location of non-aggressive vs aggressive lesions
Non -> anywhere
Aggressive -> metaphysis (primary bone tumour) or diaphyseal (metastatic bone tumor)
190
Bone destruction type of non-aggressive vs aggressive lesions
Non -> geographic
Aggressive -> permeative
191
Cortical disruption of non-aggressive vs aggressive lesions
Non -> none
Aggressive -> broken or not seen, path fractures
192
Zone of transition of non-aggressive vs aggressive lesions
Non -> sharp, distinct
Aggressive -> Indistinct, permeative, long zone of transition
193
Periosteal reaction of non-aggressive vs aggressive lesions
Non -> smooth continuous
Aggressive -> Interrupted, variable, spiculated, amorphous
194
What is hypertrophic osteopathy? What is it caused by?
Increased periosteal bone formation in long bones - starts distal and moves proximal
Mostly metatarsus and metacarpus
Caused by cardiopulmonary disease or neoplasia (pulmonary or intra-abdominal)
195
Signs of hypertrophic osteopathy
Increased blood to extremities
Periosteal new bone formation (brush border to palisading) on digits and progressively extends proximally
Swollen extremities, lameness
Secondary to thoracic disease
196
6 types of epiphyseal disorders
Osteochondrosis
Ununited anconeal process
Fragmented medial coronoid process
Hip dysplasia
Aseptic necrosis of the femoral head
Epiphyseal dysplasia
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What is osteochondrosis AKA
Developmental orthopaedic disease
198
What is the cause of osteochondrosis?
Dysfunction of endochondral ossification (cartilage doesnt ossify properly and becomes thickened instead)
May necrose and cause cartilage flap -> Osteochondritis dessicans (OCD)
199
Who and where does osteochondrosis normally affect?
Large breed dogs 4-10 monthsold
Bilateral
Shoulder (most common), elbow, stifle, tarsus, retained endochondral cartilage core (ulna), ununited anconeal process
## Footnote
focal area of endochondral ossification causing cartilgae thickening that can necrose, cause fissure, become a fragment seen on rads
200
radiographic signs of osteochondrosis
Subchondral bone defect
Subchondral sclerosis (more bone laid down)
Calcified glap of cartilage free in joint (OCD, joint mouse)
Joint effusion and widened joint
Sometimes see gas in shoulder joint
201
Population affected by elbow osteochondrosis and location in elbow
Males more than females
5-10 months old large breeds
Get a subchondral defect of the medial condyle and subchondral sclerosis
elbow (medial humeral condyle) is the second most common location after the shoulder
202
Lesions seen in stifle osteochondrosis
Lateral condylar surface more commonly affected
Defect or flattening in articular surface
Subchondral swelling
Mineralised flap
Secondary osteoarthritis
203
Lesions seen in tarsus osteochondrosis
Medial trochlear ridge (talus) most common
Widening of joint space
Flattened trochlear ridge
Subchondral sclerosis
Caudal mineralised flap
Secondary osteoarthritis
Tarso-crural effusion
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4 causes of elbow dysplasia
Genetics
overnutrition
joint incongruity
Specific joint disorders -> ununited anconeal process, fragmented medial coronoid process
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Ununited anconeal process -> breed, when it should be fused by, radiographic view
German shepherds - large breed dogs have separate anconeal ossification centre
5 months
Bilateral 30%
Males 2x more likely
Flexed ML view of the elbow
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Radiographic findings of ununited anconeal process
Radiolucent line separating anconeal process from olecranon after 20 weejs
Line irregular and of variable width
Ends on either side of physis sclerotic, secondary osteoarthritis
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Fragmented medial coronoid process -> breed, age, radiographic view
Medium - large breeds
Males
4-6 months of age
cranio15 degree lateral caudomedial oblique
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Fragmented medial coronoid process radiographic signs
ML -> sclerosis in interosseous space between proximal ulna and radius
Degenerative changes (osteophytic) on anconeal process and medial epicondyle
Rare to see actual fragment
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Hip dysplasia - who, bilateral or unilateral, underlying process
Large dogs but also small dogs and cats
Inherited, not present at birth - develops due to joint laxity leading to abnormal hip development and secondary osteoarthritis
Usually bilateral but can be unilateral
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Normal hip joints description
Deep cup shaped acetabulum
Smooth circular margin femoral head
>2/3 of head in dorsal rim
Parallel joint space
Narrow femoral neck
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Changes in HD in order of appearance
1. Subluxation of 1 or both femoral heads
2. Perichondral enthesophytes
3. Remodelling of femoral head and neck
4. Remodelling of the acetabulum
5. Sclerosis of subchondral bone of femoral head and acetabulum
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Abnormal radiographic findings of HD
Shallow acetabulum
Flattening and subluxation of femoral head
Thickened femoral necks
Subchondral sclerolsis
Enthesophytes - bony spur arising from pulling of tendons or ligaments forming "morgans line"
213
What is the norberg angle?
Measurement made from extended limb VD
Number represents laxity -> normal more than 105, abnormal less than 90, borderline in between
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How does the feline coxofemoral joint differ from that of a dog?
It has shallower acetabulum reflected in the norberg angle being 92.4
215
Who does aseptic necrosis of the femoral head affect?
| Legg-Calves Perthes disease
Small young dogs -> terriers, poodles, chihuahua
3-10 months old
Not in cats -> but analagous condition called capital physeal dysplasia in cats
216
What is aseptic necrosis of the femoral head
Femoral head loses blood supply and becomes necrotic
can subluxate and then get degenerative changes
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Initial and then progressive radiographic signs of aseptic necrosis of the femoral head
Unilateral or bilateral coxofemoral oesteoarthritis
Intially -> lysis of femoral head, mottled pattern of patchy lysis due to bone necrosis
Progresses to -> femoral head collapse, changes in opacity and remodelling of femoral neck
Finally -> joint remodels to a shallow acetabulum, wide joint space, DJD, muscle atrophy
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What is epiphyseal dysplasia?
Incomplete ossification of humeral condyles leading to humeral condylar fractures with normal exercise
The other elbow can have fissure lines and coronoid process fragmentation too so check this
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Who does epiphyseal dysplasia affect?
Hereditary in spaniels, pure and cross bre
Mostly males
220
When should the humeral condyles be ossified by?
84d
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6 physeal disorders
1. Physeal (growth plate) trauma
2. Rickets
3. Feline femoral capital physeal dysplasia
4. Endochondral osteodystrophy
5. Retained cartilagenous core
6. Osteochondroma
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What does physeal trauma cause?
Closure of a growth plate prematurely causing bowing of other bone that still grows
eg radius or ulna
223
What is rickets?
Excessive growth of physeal cartilage, a result of endochondral ossification failure on the metaphyseal side of the physis
Occurs in animals not getting enough nutrition and physis keeps widening
224
What is feline femoral capital physeal dysplasia and who does it affect?
Young male cats - heavy and desexed <6mo
Spontaneous capital physeal separation - usually unilateral, dysplasia of chondrocytes in growth plate
225
Radiographic signs of feline femoral capital physeal dysplasia
Capital separation, osteolysis+ sclerosis of femoral neck
Apple core appearance of femoral neck
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1 diaphyseal disorder
Panosteitis
227
Panosteitis - who does it affect, what is it
Unknown cause - could be viral, not inflammatory
Affects large breed dogs - male german shepherds between 5-12 months of age, unexplained painful lameness shifting from one leg to the other
Present in one or more tubular bones of appendicular skeleton
Thumb print like appearance
228
Radiographic signs of panosteitis
Increased intra-medullary radio-opacity
Loss of trabecular pattern - hazy opacity
Diffuse granular appearance of increased opacity (thumbprints)
Endosteal bone thickening
Smooth periosteal new bone
Near nutrient foramen
Eventually normal remodelling
229
2 metaphyseal disorders
1. Hypertrophic osteodystrophy
2. Congenital bone cysts
230
Hypertrophic osteodystrophy - who it affects, what it is
Rapidly growing large dogs 2-7 months old
Cause unknown
Metaphyses of long bones swollen and painful, inflammatory response that is self-limiting with fever and diarrhoea sometimes seen
translucent zone appears in metaphysis parallel and adjacent to the physis then new periosteal bone deposited all the way around metaphysis (flaring and sclerosis of the metaphysis)
Soft tissue swelling and premature closure of physis may occur
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Which bones does hypertrophic osteodystrophy affect?
Distal radius and ulna
May also affect axial skeleton
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What is retained endochondral cartilage core?
A failure of endochondral ossification that most commonly affects the distal ulnar physis.
Common in large breeds
Can retard growth of ulna resulting in radius curvus and valgus deformity
Physis is normal
Bilaterally symmetrical
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What are congenital monostotic bone cysts?
Slow expansile lesions of metaphysis with smooth margins, firm non painful swelling and pathological fractures
Benign and slow growing but weaken cortex
Large and giant breeds
234
What is an osteochondroma? Where is it normally?
Abbherant growth centre causing focal outgrowth of bone that grows until physes close
Often on distal ulna impinging into normal radius
Benign
| Causes feline leukaemia virus in cats
Inherited in dogs
235
Where are osteochondroma on vertebrae and ribs?
Peri-metaphyseal periosteal location
236
3 congenital generalised bone disorders
Dwarfism - many disorders in here
Osteopetrosis
Scottish fold osteodystrophy
237
2 acquired nutritional bone disorders
Nutritional hyperparathyroidism
Hypervitaminosis A
238
1 congenital or acquired bone disorder
Renal hyperparathyroidism
239
2 types of dwarfism syndromes
Disproportionate or proportionate
240
Disproportionate dwarfism characteristics
Part of skeleton reduced
Skull and spine unaffected, limbs shortened
Dashies
Short legged, chondrodystrophoid changes in long bones
241
Proportionate dwarfism syndromes and examples in dogs and cats
Entire skeleton reduced in size - toy poodles
Dogs - hypopituitary/hypothyroid german shepherds
Cats - mucopolysaccharidosis -> siamese eg, it is a genetic lysosomal storage disease with abnormal facial appearance, cloudy corneas
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What is chondrodysplasia?
Dwarfism syndrone inherited - normal in dashies
bone development and physeal closure times are same as in non-chondrodystrophic animal
Abnormal in labs, alaskan malamute
Appendicular bones are short, tubular and bowed with widened metaphysis
Vertebrae are sqaure
243
What is congenital epiphyseal dysplasia?
A dwarfism syndrome
Hypothyroidism and low growth hormone levels
Patchy ossification in epiphysis - stippled
Beagles
244
What is osteochondral dysplasia?
Disorders of development of bones
Metatarsals short and misshapen
Severe osteoarthritis
Scottish folds
245
What is the cause of osteopetrosis? What do we see?
Congenital rare hypervitaminosis D with excess bone formation and increased opacity in medulla
Thickened cortices
Bones are brittle and fracture easily
246
What is secondary nutritional hyperparathyroidism?
Failure of osteoid to calcify due to Ca:P imbalance or vitamin D deficiency
Osteopaenia due to osteomalacia -> decreased radio-opacity of bone, cortical thinning, prominant trabeculae, soft bones, metaphyseal bone remains with good well mineralised opacity
247
What syndrome does renal secondary hyperparathyroidism cause in dogs?
Rubber jaw
248
Who does hypervitaminosis A affect?
Cats with liver rich diet
Causes periarticular bone formation and ankylosis (fusion of bones) of affected joints -> kangaroo cats
249
Causes of monoarticular joint problems
Trauma, neoplasia, septic
250
Causes of multi-articular lameness
Polyarthritis, geriatric osteoarthritis
251
9 radiographic signs of joint disease
1. Increased synovial mass
2. Altered thickness of the joint space
3. decreased or increased subchondral bone opacity
4. Subchondral cyst formation
5. Altered perichondral bone opacity, enthesophytes or osteophytes
6. Mineralisation of joint soft tissues
7. Intraarticular calcified bodies
8. Joint luxation/subluxation
9. Joint malformation
252
Causes of decreased subchondral bone
Inflammatory exudates or infectious arthritis
Developmental -> disease where cartilage does not ossify
253
Causes of widened joint space
Early in disease -> synovial effusion
Ligament damage also
254
Cause of narrowing joint space
Cartilage erosion
255
Where is perichondral bone?
Where synovium merges with articular cartilage
256
Causes of decreased subhondral bone opacity
Inflammatory exudates
Infectious arthritis can also extend into subchondral bone
257
Causes of increased subchondral bone opacity
Degenerative joint disease (benign joint disease)
258
What is an osteophyte?
New bone formation at periarticular margins
will be right near joint - otherwise it is an enthesophyte
259
Causes of increased perichondral bone opacity
Ossification of fibrocartilage on chondrosynovial junction produces enthesophytes (new bone formation from traction at osseous attachments) that can incorporate into the joint capsule
this happens in osteoarthritis
260
Causes of decreased perichondral bone opacity (at the chondrosynovial junction)
Inflammation of the synovial membrane causes the adjacent bone to appear irregular
Immune mediated diseases and villonodular synovitis
261
3 causes of large accumulations of articular or periarticular calcific material
osteochondroma in joints of dogs and cats
pseudo-gout (calcium pyrophoshate deposition disease)
intra-meniscal calcificiation and ossification in cats stifles
262
What are joint mice? what are the 3 catagories?
Intra-articular calcified bodies
not all are free in the joint
1. Avulsed fragment of articular or periarticular bone
2. Osteochondral components of a disintegrating joint surface
3. Small synovial osteochondromas
263
Who suffers with medial luxation of the patella?
Toy dogs and devon rex cats
264
What is the most common joint problem? What are its causes?
Osteoarthritis - DJD increases with age
Usually secondary, but primary in older patients
Old age
Secondary to developmental disorder - hip dysplasia, elbow dys.
Aquired - trauma, post joint infection
265
Progressive radiographic signs of DJD
Synovial effusion compressing the intrapatellar fat pad and displacing caudal fascial planes caudally
Periarticular enthesopathy and osteophytes
266
Progressive changes of DJD
Narrowing of joint space
Sclerosis of subchondral bone
Osteophytes
Enthesophytes
Complete ankylosis (final stage)
267
Osteoarthritis in cats features
Tend to produce exuberant periarticular new bone
Intra-articular mineralisation is more common
268
Two types of polyarthritis
Erosive -> immune mediated - IgG auto-antibodies. Swelling seen, narrow joint spaces, joint effusion, subluxation, destruction of articular bone
Non-erosive -> dogs, immune mediated. Radiographs only show intracapsular sweling and in severe cases OA
269
Most commonly affected joints of erosive arthritis (rheumatoid)
Carpus
Tarsus
Phalanges
270
Cause of non-erosive polyarthritis
Systemic lupus erythematosis in dogs and cats - anaemia, nephropathy, pericarditis, skin disease
271
4 types of immune mediated feline polyarthropathy
1. Periosteal proliferative polyarthritis - most common form, young male cats extremities and systemic illness
2. Rheumatoid arthritis (erosive form in older cats)
3. SLE - antinuclear antibodies in blood, no distinct rad signs
4. Idiopathic polyarthritis -> myeloproliferative disease association (no distinct rad signs). Needs bone marrow biopsy
272
Initial signs of septic arthritis
Non-specific to any effusive non-erosive joint disease
Synovial effusion, increased synovial mass and widened joint space
273
What can septic arthritis spread from?
An associated osteomyelitis
274
Progressive radiographic signs of septic arthritis
Diminished radiolucent joint space (destruction of articular cartilage)
Subchondral bone destruction (more severe than OA)
Advanced -> weight bearing surfaces collapse
275
Types of septic arthritis
Physeal
Epiphyseal
Synovial
Tarsal bones
Carpal bones
276
2 most common neoplasias of joints
Synovioma
Synovial cell carcinoma
277
Neoplasia of joints vs primary bone tumours
Neoplasia of joints affects the bone either side of the joint and are primarily lytic
Bone tumours dont
278
Most commonly affected joints for synovial cell carcinoma
Uncommon in dog and rare in cat
Stifle and elbow
279
4 radiographic signs of severe sprains
1. Periarticular soft tissue swelling
2. Avulsion fractures at points of attachment of ligaments, tendons and capsules to bone
3. Signs of joint instability or subluxation
4. Spatial derangement of osseous components of the joint
280
Signs of cruciate ligament injury
Enthesopathy at the insertion of the cranial cruciate ligament on the cranial aspect of the tibial plateau
Intracapsular soft tissue swelling
Thickening of medial joint capsule
281
Bicipital tendinopathy signs
Large breeds
Intermittent weight bearing front limb lameness
Focal mineralised bodies (osteophytes) near greater tubercle
Remodeling of supraglenoid tubercle
