Bone: Diagnostic Imaging Flashcards
Is an MRI or a CT more expensive?
MRI
When is the “right” time to x-ray to obtain the best imaging result?
From those cases where clinical signs are severe or persistent/recurrent despite treatment
What 6 things are altered for a good x-ray?
- Positioning
- Centring
- Collimation
- Exposure/processing (darkness, contrast, resolution)
- Labelling
- Artefacts
What views are needed for a radiograph?
- Take at least 2 views
- ± contra-lateral limb for comparison
What can bone abnormalities be classified according to within the skeleton to help understand what is going on? Give 2 examples (3)
Distribution
–Only one/many bone(s) involved
–Involving just one bone region (e.G. Metaphyses) or generalised (all regions)
–Symmetrical or assymetrical
What 3 things do we comment on with the presence of lesions on radiogrpahs?
- Number
- Size
- Shape
What 3 things do we comment on with the location of lesions on radiographs?
- Bone
- Region
- Surface
What 2 things do we comment on with the presence of lesions on radiographs?
- Radiopacity - bone production or lysis?
- Margination
Label
a. Medullary cavity
b. Endosteum of cortex
c. Cortex
d. Periosteum surface
Label
A) Physis
B) Epiphysis
C) Metaphysis
D) Diaphysis
E) Metaphysis
F) Epiphysis
G) Physis
What is the term for bone loss?
Osteopenia
Osteopenia is always bad, but what are the 2 forms?
- Reversible e.g. Disuse – reduce loading, but if you load again it will loose again
- Irreversible e.g. Neoplasia
What is sclerosis?
Increased bone density
What is Wolff’s law?
Response to increased or abnormal loading
What can sclerosis be in response to? (2)
–Response of bone to wall-off ‘pathology’ e.g. infection, cyst
–Response to increased or abnormal loading: Wolff’s Law
Discuss this radiograph?
Hip dysplasia, cranial acetabulum edge increased opacity
Discuss this radiograph
Bone infection – surrounding has increased opacity
Name two things giving an appearance of new bone (3)
- Superimposition of structures (bone or soft tissue)
- Adjacent bone loss
- Foreign material e.g. on coat
Name a cause of an appearance of bone loss on radiographs (2)
- Gas, or defect in soft tissues
- Mach lines – where 2 bones overlap (mimics hairline fractures)
Define an aggressive lesion
Rapid bony change = minimal time for bone to remodel. Appearance is disorganised
Define a non-aggressive lesion
Slow-growing, benign more chronic process – remodelling possible. More structured reaction.
What 6 things do we look at to assess appearance of lesions?
- Bone destruction (lysis)
- Periosteal reaction
- Lytic edge character
- Cortical disruption
- Transition from normal to abnormal bone
- Rate of change (10-14 days)
Label these bone lysis patterns
A) Geographic lysis - least aggressive
B) Geographic lysis - more aggressive
C) Moth eaten lysis
D) Permeative lysis
Label these periosteal reaction patterns
A) Solid
B) Lamellar (parallel)
C) Lamellated
D) Thick brush like
E) Thin bursh like
F) Sunburst
G) Amorphous bone production
If there is a varying degree of aggressivenes in a lesion, how would you analyse the aggressiveness?
Use the most aggressive aspect
How aggressive is degenerative joint disease?
Non-aggressive
How aggressive is neoplasia?
Aggressive if malignant, non-aggressive if benign
How aggressive is an infection?
Following radiographs, how can you confirm your diagnosis?
Usually requires a biopsy (FNA, incisional or excisional), and subsequent histopathological examination.
Name a huge advantage of using a CT over x-ray (2)
- Eliminate superimposition
- 3D reconstruction
What is an MRI good to use for imaging?
Soft tissue and joints
How does scintography work?
increased uptake of radioisotope in regions of inflammation = non-specific.
What is this?
Osteoarthritis
Label what is seen in degenerative joint disease
A) Increased subchondral bone density
B) Free mineralised fragments
C) Osteophytes
Label this image of degenerative joint disease.
A) Mild osteoarthiritis: roughended, thinning catilage
B) Severe osteoarthiritis: Thickened damaged bone with no covering cartilage
C) Thickened, infammed synovium
Name 5 radiohraphic signs of degernative joint disease (7)
–Soft tissue swelling / joint effusion
–Changes in subchondral bone opacity
–Changes in joint space = Initially widens due to effusion, then narrows due to cartilage erosion
–Osteophyte formation = Form at chrondrosynovial junction, on non-weight-bearing surfaces
–Joint mice or osteochondral fragments within the joint cavity
–Joint subluxation (hip joint)
–Cyst formation (rare)
Discuss what is seen here
Degenerative joint disease:
- Soft tissue swelling
- Some compression of infrapatellar fat pad
- Osteophyte formation
- Caudally at the joint= increased opacity
- Fat ad usually goes into the joint and hear we have a joint effusion
Where are the typical sites for osteophytes on the stifle?
–Proximal/distal patella
–Proximal trochlear ridge (femur)
–Both femoral epicondyles
–Fabellae
–Proximal tibia
What are the typical locations for osteophytes on the elbow?
–Dorsal anconeal process (ulna) is the first place
–Cranial joint aspect
–Lateral epicondylar crest (humerus)
–Medial epicondyle (humerus)
–Medial coronoid process (ulna)
–Trochlear notch (ulna)
What type of bone disease is metabolic bone disease?
Generalised - will be everywhere
What radiographic changes are seen with metabolic bone disease? What is the exception?
•Usually a decrease in opacity = osteopenia loss of bone
(except VitA excess in cats (eating liver) – increased bone)
Discuss this radiograph
Nutritional secondary hyperparathyroidism
Lack of bone opacity
Thin cortices, and folding fracture
Bone isn’t opaque cf soft tissue
What causes metabolic disease in reptiles?
- Inappropriate feeding and/or husbandry
- Imbalance of Ca, P, or Vit D in body
- Usually too low dietary Ca or Vit D or excess P
What is seen in a reptile with metabolic disease?
- Lethargy, reluctance to move
- Results in Osteopenia
- Pathological fractures, folding fracture
What do these pictures show?
Metaphyseal osteopathy
What type of lesion is Metaphyseal osteopathy and where does it affect?
Localised lesion affecting multiple long bones
What type of dogs does Metaphyseal osteopathy affect?
Young, medium-large breed dogs
What early changes are seen with Metaphyseal osteopathy?
Radiolucent line adjacent to metaphyses
What later changes are seen with Metaphyseal osteopathy?
Periosteal new bone formation and sclerosis
What clinical signs are seen with Metaphyseal osteopathy?
Pain, (± pyrexic and systemically ill)
What is this?
Hypertrophic osteopathy
A) What is Hypertrophic osteopathy?
B) Which species?
C) Which bones are affected first?
D) What is it secondary to?
A Periosteal new bone formation, Soft tissue swelling, No joint involvement or bone destruction
B) All species, but commonest in dogs
C) Metacarpal / metatarsal bones affected first, but then spreads to other bones
D) To space-occupying lesion in thorax or abdomen.
A) What can be seen?
B) Who is affected?
C) What is it?
D) Where is there a poorer prognosis?
A) Craniomandicular osteopathy
B) Young Westies and Scotties
C) Reactive periosteal new bone formation on mandible and ventral skull bones. Increased bone density
D) If it involves temporomandibular joint (TMJ) due to interference with joint movement
What is this?
Panosteitis
What is commonly seen in Panosteitis? Include radiographic changes
- Shifting lameness in young growing dogs esp. GSD
- May be polyostotic
- Increased opacity of medullary canal – irregular, heterogenous
- ‘Thumb prints’ (wont always see this)
- Thickening of cortical bone
- Often centered around nutrient foramina
- Affects fore legs more commonly than hind legs
How do you treat panosteitis?
Self limiting - make a full recovery
What is this?
Immune-mediated polyarthritis
What is seen with Immune-mediated polyarthritis?
Painful, stiff, depressed animal often with swollen joints and ligamentous laxity
- Bony changes in erosive form only
- Multiple lytic lesions, around and ‘crossing’ joints
- Affects all joints, but changes most common / initially seen in carpi and hocks
What does this show?
Bone cysts
Bone cysts:
A) What is often seen?
B) What should be checked?
C) Where are the predilection sites?
A)
- Degenerative or developmental
- Often single, can be multiple
- Usually oval/circular, and well marginated +/- sclerotic rim
- Usually near joints
B) Check contra-lateral limb
C) Equine stifle and fetlock
What is this?
Neoplasia
What 2 things with fractures can cause ostepenia?
- Disuse atrophy
- Stress production
Is this okay?
Yes, there is some osteopenia but this is from disuse
Is this okay?
This is bad, there is a pathological fracture; been immobilised too much
What is this?
Lost cortex of bone in CdCr joint
Pathological fracture
What is osteomyelitis?
- Soft tissue swelling
- Irregular periosteal reaction (often semi-aggressive)
- Often more extensive than fracture callus. Callus is well structured.
Label this.
Note it is from a horse with chornic discharge from site of previou sinus surgery.
A) Sequestrum (piece of dead bone)
B) Involucrum (new bone walling it off)
What is this?
Bone cyst - non aggressive
What is this?
Bone tumour and aggressive
