Principles of Radiology

Question 1

Radiopaque centers in bones can be used for?

Answer 1

Radiopaque centres can be used to determine the bone age of children

i.e growth delays etc

Question 2

What is the first thing to do with radiographs?

Answer 2

Check names and film is around the correct way

Question 3

What are the ABCS of skeletal x rays?

Answer 3

A-Alignment
B-Bones
C-Cartilage
S-Soft tissues

Question 4

What to look for in alignment?

Answer 4

Subluxed; Partially aligned

Dislocated; Not aligned.

Question 5

When checking alignment of the long bone would should be included?

Answer 5

Two views are taken at 90 degrees to appreciate full displacement.

Should also include the joint at both ends to access involvement and any rotation.

Question 6

What to look for in the bones?

Answer 6

• Shape, expansion or thinning
• Cortical continuity.
• Development i.e epiphysis, ossification
• Sclerotic (too dense)
• Lucent (not dense enough)
• Uniform texture i.e tumour or infection

Question 7

What to look for in cartilage?.

Answer 7

• Increased joint space i.e infection, tumor, trauma
• Decreased joint space, Degeneration, inflam
• Calcification (chondrocalcinosis)

Question 8

What to look for in soft tissues?

Answer 8

• Masses (can be calcified)
• Gas, infection and trauma
• Foreign body
• Joint effusion with/without blood/lipid fluid level as can be found in trauma
• Fat pad sign due to displacement of normal tissues by a fluid distended joint.

Question 9

What is the checklist for a fracture (1-4)

Answer 9

• L or R
• How many bones
• How many bone fragments, simple (2), comminuted (3+)
• Open or closed

Question 10

What is the checklist for a fracture (5-8)?

Answer 10

• Fracture line involve the joints? (intra-articular?)
• Position, i.e diaphyseal, distal 1/3 etc
• Relationship of fragments (Convention distal to proximal)
• Describe how much the distal fragment is displaced; ventro-dorsally and side to side from proximal fragment.

Question 11

What is the checklist for a fracture (9-11)?

Answer 11

• Describe the overlap
• Angulation
• Rotation

Question 12

What are the advantages of plain radiographs?

Answer 12

• Excellent for initial examination of bone and bone texture
• Inexpensive
• Readily available

Question 13

What are the disadvantages of plain radiographs?

Answer 13

• Poor for visualisation of soft tissues and non-bony components of joints
• Contrast requires invasive procedure
• 2D
• Ionizing radiation but relatively low

Question 14

What are advantages of CT scan?

Answer 14

• Excellent for bone and bone texture
• 3D useful for surgery reconstruction and planning
• Moderate visualisation of soft tissues and non bony components of joints w/o contrast
• Ready available
• Can use contrast agent to enhance soft tissues

Question 15

What are the disadvantages of CT scan?

Answer 15

Large ionizing radiation

Question 16

What are the advantages of MRI?

Answer 16

• Excellent for soft tissues and joints
• Can be used to identify edema and bone displacemnt
• Multiplanner acquisition, useful for surgical planning
• Can use contrast agent
• No ionising radiation

Question 17

What are the disadvantages of MRI?

Answer 17

• Expensive
• Not readily available
• Cant have metal implants
• Claustraphobic
• Long scan, keep still
• Children might need general anaesthesia

Question 18

What are the advantages of ultrasound?

Answer 18

• Soft tissues and joints (penetration limited)
• low cost
• no ionizing radiation
• can sometimes use contrast
• inexpensive
• real time
• readily available

Question 19

What are the disadvantages of ultrasound?

Answer 19

• Operator dependant

- Cannot penetrate bone or air

Question 20

What are the advantages and disadvantages of technitium 99 bone scans?

Answer 20

• Metabolically active bone
• Malignancy
• high sensitivity

Disadvantages

• Radiation
• poor specificity
• Expensive
• not available