Bone: Diagnostic Imaging

Question 1

Is an MRI or a CT more expensive?

Answer 1

MRI

Question 2

When is the “right” time to x-ray to obtain the best imaging result?

Answer 2

From those cases where clinical signs are severe or persistent/recurrent despite treatment

Question 3

What 6 things are altered for a good x-ray?

Answer 3

• Positioning
• Centring
• Collimation
• Exposure/processing (darkness, contrast, resolution)
• Labelling
• Artefacts

Question 4

What views are needed for a radiograph?

Answer 4

• Take at least 2 views
• ± contra-lateral limb for comparison

Question 5

What can bone abnormalities be classified according to within the skeleton to help understand what is going on? Give 2 examples (3)

Answer 5

Distribution

–Only one/many bone(s) involved

–Involving just one bone region (e.G. Metaphyses) or generalised (all regions)

–Symmetrical or assymetrical

Question 6

What 3 things do we comment on with the presence of lesions on radiogrpahs?

Answer 6

• Number
• Size
• Shape

Question 7

What 3 things do we comment on with the location of lesions on radiographs?

Answer 7

• Bone
• Region
• Surface

Question 8

What 2 things do we comment on with the presence of lesions on radiographs?

Answer 8

• Radiopacity - bone production or lysis?
• Margination

Question 9

Label

Answer 9

a. Medullary cavity
b. Endosteum of cortex
c. Cortex
d. Periosteum surface

Question 10

Label

Answer 10

A) Physis

B) Epiphysis

C) Metaphysis

D) Diaphysis

E) Metaphysis

F) Epiphysis

G) Physis

Question 11

What is the term for bone loss?

Answer 11

Osteopenia

Question 12

Osteopenia is always bad, but what are the 2 forms?

Answer 12

• Reversible e.g. Disuse – reduce loading, but if you load again it will loose again
• Irreversible e.g. Neoplasia

Question 13

What is sclerosis?

Answer 13

Increased bone density

Question 14

What is Wolff’s law?

Answer 14

Response to increased or abnormal loading

Question 15

What can sclerosis be in response to? (2)

Answer 15

–Response of bone to wall-off ‘pathology’ e.g. infection, cyst

–Response to increased or abnormal loading: Wolff’s Law

Question 16

Discuss this radiograph?

Answer 16

Hip dysplasia, cranial acetabulum edge increased opacity

Question 17

Discuss this radiograph

Answer 17

Bone infection – surrounding has increased opacity

Question 18

Name two things giving an appearance of new bone (3)

Answer 18

• Superimposition of structures (bone or soft tissue)
• Adjacent bone loss
• Foreign material e.g. on coat

Question 19

Name a cause of an appearance of bone loss on radiographs (2)

Answer 19

• Gas, or defect in soft tissues
• Mach lines – where 2 bones overlap (mimics hairline fractures)

Question 20

Define an aggressive lesion

Answer 20

Rapid bony change = minimal time for bone to remodel. Appearance is disorganised

Question 21

Define a non-aggressive lesion

Answer 21

Slow-growing, benign more chronic process – remodelling possible. More structured reaction.

Question 22

What 6 things do we look at to assess appearance of lesions?

Answer 22

• Bone destruction (lysis)
• Periosteal reaction
• Lytic edge character
• Cortical disruption
• Transition from normal to abnormal bone
• Rate of change (10-14 days)

Question 23

Label these bone lysis patterns

Answer 23

A) Geographic lysis - least aggressive

B) Geographic lysis - more aggressive

C) Moth eaten lysis

D) Permeative lysis

Question 24

Label these periosteal reaction patterns

Answer 24

A) Solid

B) Lamellar (parallel)

C) Lamellated

D) Thick brush like

E) Thin bursh like

F) Sunburst

G) Amorphous bone production

Question 25

If there is a varying degree of aggressivenes in a lesion, how would you analyse the aggressiveness?

Answer 25

Use the most aggressive aspect

Question 26

How aggressive is degenerative joint disease?

Answer 26

Non-aggressive

Question 27

How aggressive is neoplasia?

Answer 27

Aggressive if malignant, non-aggressive if benign

Question 28

How aggressive is an infection?

Question 29

Following radiographs, how can you confirm your diagnosis?

Answer 29

Usually requires a biopsy (FNA, incisional or excisional), and subsequent histopathological examination.

Question 30

Name a huge advantage of using a CT over x-ray (2)

Answer 30

* Eliminate superimposition * 3D reconstruction

Question 31

What is an MRI good to use for imaging?

Answer 31

Soft tissue and joints

Question 32

How does scintography work?

Answer 32

increased uptake of radioisotope in regions of inflammation = non-specific.

Question 33

What is this?

Answer 33

Osteoarthritis

Question 34

Label what is seen in degenerative joint disease

Answer 34

A) Increased subchondral bone density B) Free mineralised fragments C) Osteophytes

Question 35

Label this image of degenerative joint disease.

Answer 35

A) Mild osteoarthiritis: roughended, thinning catilage B) Severe osteoarthiritis: Thickened damaged bone with no covering cartilage C) Thickened, infammed synovium

Question 36

Name 5 radiohraphic signs of degernative joint disease (7)

Answer 36

–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)

Question 37

Discuss what is seen here

Answer 37

Degenerative joint disease: ## Footnote * 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

Question 38

Where are the typical sites for osteophytes on the stifle?

Answer 38

–Proximal/distal patella –Proximal trochlear ridge (femur) –Both femoral epicondyles –Fabellae –Proximal tibia

Question 39

What are the typical locations for osteophytes on the elbow?

Answer 39

–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)

Question 40

What type of bone disease is metabolic bone disease?

Answer 40

Generalised - will be everywhere

Question 41

What radiographic changes are seen with metabolic bone disease? What is the exception?

Answer 41

•Usually a decrease in opacity = osteopenia loss of bone (except VitA excess in cats (eating liver) – increased bone)

Question 42

Discuss this radiograph

Answer 42

Nutritional secondary hyperparathyroidism Lack of bone opacity Thin cortices, and folding fracture Bone isn’t opaque cf soft tissue

Question 43

What causes metabolic disease in reptiles?

Answer 43

* 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

Question 44

What is seen in a reptile with metabolic disease?

Answer 44

* Lethargy, reluctance to move * Results in Osteopenia * Pathological fractures, folding fracture

Question 45

What do these pictures show?

Answer 45

Metaphyseal osteopathy

Question 46

What type of lesion is Metaphyseal osteopathy and where does it affect?

Answer 46

Localised lesion affecting multiple long bones

Question 47

What type of dogs does Metaphyseal osteopathy affect?

Answer 47

Young, medium-large breed dogs

Question 48

What early changes are seen with Metaphyseal osteopathy?

Answer 48

Radiolucent line adjacent to metaphyses

Question 49

What later changes are seen with Metaphyseal osteopathy?

Answer 49

Periosteal new bone formation and sclerosis

Question 50

What clinical signs are seen with Metaphyseal osteopathy?

Answer 50

Pain, (± pyrexic and systemically ill)

Question 51

What is this?

Answer 51

Hypertrophic osteopathy

Question 52

A) What is Hypertrophic osteopathy? B) Which species? C) Which bones are affected first? D) What is it secondary to?

Answer 52

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.

Question 53

A) What can be seen? B) Who is affected? C) What is it? D) Where is there a poorer prognosis?

Answer 53

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

Question 54

What is this?

Answer 54

Panosteitis

Question 55

What is commonly seen in Panosteitis? Include radiographic changes

Answer 55

* 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

Question 56

How do you treat panosteitis?

Answer 56

Self limiting - make a full recovery

Question 57

What is this?

Answer 57

Immune-mediated polyarthritis

Question 58

What is seen with Immune-mediated polyarthritis?

Answer 58

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

Question 59

What does this show?

Answer 59

Bone cysts

Question 60

Bone cysts: A) What is often seen? B) What should be checked? C) Where are the predilection sites?

Answer 60

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

Question 61

What is this?

Answer 61

Neoplasia

Question 62

What 2 things with fractures can cause ostepenia?

Answer 62

* Disuse atrophy * Stress production

Question 63

Is this okay?

Answer 63

Yes, there is some osteopenia but this is from disuse

Question 64

Is this okay?

Answer 64

This is bad, there is a pathological fracture; been immobilised too much

Question 65

What is this?

Answer 65

Lost cortex of bone in CdCr joint Pathological fracture

Question 66

What is osteomyelitis?

Answer 66

* Soft tissue swelling * Irregular periosteal reaction (often semi-aggressive) * Often more extensive than fracture callus. Callus is well structured.

Question 67

Label this. Note it is from a horse with chornic discharge from site of previou sinus surgery.

Answer 67

A) Sequestrum (piece of dead bone) B) Involucrum (new bone walling it off)

Question 68

What is this?

Answer 68

Bone cyst - non aggressive

Question 69

What is this?

Answer 69

Bone tumour and aggressive