Skeletal Imaging

• author "me"
• tags ""
• description "Radiographic differential diagnosis"
• fileName "Imaging"
• freezingBlueDBID -1.0
• Aseptic necrosis -legg calve perthes disease

Bilateral or unilateral collapse of the femoral neck with a moth eaten appearance of the femoral head.

Caused by an underlying abnormality in the joint or supporting structures

No bony changes but there is effusion in the effected joint

Caused by an underlying abnormality in the joint or supporting structures

Bone remodelling in periarticular tissues (osteophyte formation) + joint capsule thickening

Joint effusion (increased soft tissue opacity in the joint)

Occur primarily in the metaphyseal region

Destructive lesion of bone + periosteal reaction

Tends to only affect a single bone and lesion rapidly changes

Invades bone by direct extension - have bone and cortical erosion where the soft tissue tumour invaded

Occurs in diaphysis

Occurs within the diaphysis (humerus and femur). May affect numerous bones

Multiple opacities within the medullary cavity + periosteal reaction

Infection of the bone usually centered in the medullary cavity (although it can localise at sites of active endochondral ossification in the metaphysis and epiphysis of long bones and vertebral bodies)

Aggressive lesion- may see a sequestrum

Rough and bumpy articular surface (sclerosis due to lack of cartilage ossification)

Joint effusion

Predilection sites - caudal aspect of the humeral head + dorsal ridge of medial trochlear of hock

Infection of the intervertebral disc space -> disc space collapse -> end plates become sclerotic and irregular due to spread of infection

New bone formation on ventral vertebral bodies

Occurs along the capital epiphysis (just below the ball of the femoral head). The femoral head remains in the acetabulum whilst the shaft of the femur moves around

Bone shows an underlying abnormality that lead to the bone being weakened

Bone may contain multiple fractures

Where a small chip has been pulled off bone by a tendon or ligament => this occurs where tendons and ligaments attach to bone

Fracture appears as a crack because the broken pieces are still in alignment

Severe gaping of joint on one side (instability)

Avulsion of bone at an attachment site (periarticular bone fragment)

Joint effusion + predominantly unilateral soft tissue swelling

Shortened ulnar and cranial bowing of the radius due to premature ulna physis closure

Irregular and thickened cortices of the radius

Visible horizontally distributed trabecular bone within the radius

Shortened radius due to premature closure of the radial growth plate

Increased humeroradial joint space

Subluxation of the hip joint due to lack of conformity between the acetabulum and the femoral head

Causes the centre of the femoral head to be outside the line of the dorsal acetabular rim

Secondary changes- osteophyte formation over the femoral neck and over the cranial acetabular edge

Alters vertebral alignment +/- compression and shortening of the vertebral body

Stair step = subluxation of a vertebrae + fracture fragment

Young animals- fracture through the physis "end plates" of the vertebral body

Alternating radiodense and radiolucent zones in the metaphysis of long bones, parallel to physis "double physeal line". This irregularity is due to necrosis of bone.

May progress to develop periosteal and extraperiosteal new bone around the metaphysis (bony reaction)

Often bilateral and often ulna and radius. Occurs in young dogs => growth plates are open.

Increased opacity in the medullary cavity in the diaphysis of long bones => cannot easily differentiate between cortex and medulla

Occurs near the nutrient foramina.

Periosteal reaction can occur

Endosteal proliferation of new bone => bumpy endosteal surface