In an x-ray of a bone what can you see?
- Cortical and medullary bone
- Can't see soft tissue
- Articular cartilage appears as joint space
What can x-rays be used to image?
- Joint dislocation
What is a fracture and what are the different types of fracture?
- A complete or incomplete break in the continuity of bone
- Can see luscent lines on x-ray
What is a compression fracture?
Occur in cancellous bone when axial load compresses bone beyond limit, difficult to see fracture line
What is a greenstick fracture?
Incomplete fractures in which the bone bends and cracks instead of breaking into separate pieces. Cortex on one side fractures. Occurs more in children as their bones are more soft and flexible
What is an epiphyseal separation fracture?
Fracture line extends through an unfused growth plate separate metaphysis and epiphysis. Seen in overweight adolescent boys during rapid growth spurts, have a limp and hip pain
What radiographich changes can be seen at the epiphysis of long bones as a child ages?
Chondyles grow with age as the cartilage ossifies, the older the child, the larger the epiphysis. Eventually the dark line of the growth plate fuses.
What is bone age?
- Look at degree of ossification of carpal bones, more bones means older
- Look at maturation of growth plates
HELPS YOU TO KNOW THE MATURITY OF THE CHILDS MSK SYSTEM
What are the stages of fracture healing?
Inflammatory --> Reparative --> Remodelling
What can you see radiographically with fracture healing?
Day 1 - Swelling
Day 4 - Soft callus forming
Day 14 - Hard callus on x-ray
Month 6 - Remodelling of callus so fracture line obscured
What are the advantages and disadvantages of CT scan for bone fractures?
+ Can see subtle undisplaced fractures
+ Soft tissue detail better than plain radiograph
+ Spiral and complex fractures can be seen much easier so good for pre-operative planning
- Motion artefact
- Allergic to contrast
When looking at a CT scan how do you work out the colours?
Air, fat and water = black
soft tissue = grey
bone = white
What are CT windows?
Manipulating the grey scale so different features and tissues can be focused on
What contrast is used mainly in MRI?
What are the three different ways to weight an image with MRI?
T1: Water is black and fat is bright
T2: Water and fat are bright
STIR (fluid sensistive): Fat is dark and fluid is bright
What are T1, T2 and STIR best for imaging?
T1 = anatomy
T2 = pathology
STIR = oedema
What are the advantages and disadvantages of ultrasound in MSK imaging?
+ No radiation
+ Excellent superficial soft tissue resolution
+ Assess nerve and tendons
+ Dynamic and image guided intervention
+ Fluid collections
- Poor deep resolution
- User dependent
What will fluid appear as on an ultrasound?
What is nuclear imaging used to diagnose?
- Areas with high metabolic activity
- Bone forming metastatic lesions, healing fractures, osteomyelitis