Radiology

Question 1

X ray

Answer 1

Passage x rays
Detector
X rays absorbed by dense materials and these turn white

Question 2

Advantages and disadvantages of X ray

Answer 2

Adv:
Quick
Available, inexpensive

Dis:
Radiation
Poor soft tissue resolution

Question 3

Roles of X rays

Answer 3

Initial imaging: fractures, joint dislocation

Evaluation of pathologies: arthritis/osteomyelitis

Question 4

Fracture healing phases

Answer 4

Inflammatory phase - haematoma
Reparative phase - angiogenesis, soft callous (2 weeks) then hard callous
Remodelling

Question 5

Types of fracture

Answer 5

Transverse, linear, oblique (non displaced/displaced), spiral, green stick, comminuted

Question 6

CT scanning

Answer 6

Radiation to build slices of body
Detailed bone structure and pathology
Can form 3D image

Question 7

Advantages and disadvantages CT

Answer 7

Adv:
Subtle undisplaced fractures more visible
Short time
Soft tissue detail better than X ray (not as good as MRI)
Can view Complex fractures in great detail - good for pre op

Disadvantages:
Higher radiation dose than X ray
Motion artefact - have to remain still
Poor soft tissue detail compared to MRI

Question 8

CT scan density units

Answer 8

Hounsfield -

Air/fat = black
water is 0 (grey black)
Soft tissue = grey
Bone = white

Question 9

Windows in CT

Answer 9

Manipulate units to view certain structures more clearly - eg bone window allows bone to be very clearly visible

Question 10

MRI process

Answer 10

Activate magnetic field
Hydrogen ions align
Radio-frequency pulses tip hydrogen ions
Re alignment times are different in different tissues

Question 11

MRI uses

Answer 11

Normal anatomy, detect pathology
Bones, joints, soft tissue
Infection of MSK
BUT poor at showing micro architecture of bone

Question 12

T1/T2 MRI

Answer 12

T1 - (anatomy defining) (water black, fat white)

T2 - (fluid defining) water very bright, fat bright

Question 13

Advantages and Disadavntages MRI

Answer 13

Adv:
Excellent soft tissue
Detailed joint anatomy
Bone marrow imaging

Dis:
Long, have to stay still
Noisy
Claustrophobic
Not compatible with pacemakers/electronic devices

Question 14

Ultrasound Adv and Disadvantages

Answer 14

Adv:
No radiation 
Excellent soft tissue - superficial
Assess tendons and nerves
Fluid collections
Foreign bodies
Dynamic (live and moving)
Guide MSK intervention

Dis:
Operator dependent (need skilled)
Poor deep tissue - difficult with obese
Limited bone and intra articular imaging

Question 15

Nuclear imaging use

Answer 15

Radioisotope labelled active drugs
Marker for biological activity

Metabolically active bone assessment to look for:
Metastatic lesions, healing fractures, osteomyelitis

Question 16

How does articular joint appear on X ray?

Answer 16

Radiolucent - joint space (gap)

Question 17

What radio graphic changes do you see during childhood

Answer 17

Ossification of epiphysis - cartilage to bone (carpal bones, epiphyseal growth plates closing)