radiology

Question 1

how does X ray work?

Answer 1

passage of X rays though an object
denser materials absorb and scatter the rays Maning not many make to the detector = white image
in less dense materials the x rays pass straight through to the detector = dark image

Question 2

advantages and disadvantages of X rays

Answer 2

ads: fast, cheap
diseases: radiation, poor soft tissue imaging

Question 3

role of X rays in acute and chromic conditions

Answer 3

acute = fractures and dislocations / trauma

chronic = bone or joint disease e.g. arthritis and osteomyelitis (bone infection)

Question 4

can you see cartilage on an X ray

Answer 4

no - looks like a joint space but is filled with cartilage

Question 5

types of fracture

Answer 5

transverse = straight horizontal line

linear = vertical line down the middle

oblique non displaced = diagonal line

oblique displaced = diagonal line and angled bone displaced

spiral = rational force - spirals round whole bone

greenstick = in children as in soft bones, bend creates a rip on extended side - can have buckle fracture on flexed side of the bend

comminuted = compaction force causes fragmentation

Question 6

embryonic bone development

Answer 6

look at body log bone section

Question 7

why can’t infections of bone spread to epiphysis of children

Answer 7

growth plate creates a gap which the infection cannot travel over

Question 8

fracture healing

Answer 8

look at body log bone section

Question 9

CT scanning?

disadvantages?

Answer 9

-computed tomography
uses radiation and X rays to create sliced images in a transverse plane of a person
good detailed images
soft tissue imaging is better than X ray
can see undisplaced, subtle, spinal and pelvic fractures better
it is short and creates 3D image

• radiation (higher than X ray)
  motion artefact if patient moves (requires stillness)
  not great soft tissue imaging

Question 10

what are hounsfield units?

Answer 10

they measure the density of body tissues
negative = black (air and fat)
water = 0 and also black
positive = grey - white (soft tissue bone and metal)

Question 11

what are windows

Answer 11

they are specific ways of viewing a CT that allow you to visualise specific structures more clearly e.g. bone window

Question 12

what is MRI?
benefits?
disadvantages?

Answer 12

-magnetic resonance imaging
uses magnetic field, hydrogen nuclei, and radio frequency pulses to create a high quality cross sectional image

-no radiation, good soft tissue imaging, used to see infections in MSK and ligament/tendon injury, good bone marrow imaging

- claustrophobic 
long (45-60mins)
expensive
uses magnets 
noisy

Question 13

T1 and T2 weighted images?

STIR

Answer 13

T1 = used to see fat and anatomy (fat is white fluid is dark grey, air is black)

T2= used to see fluid (water is white, fat is light grey, air is black)

STIR = used to suppress fat imaging - very good at fluid imaging

Question 14

ultrasound advantages and disadvantages?

Answer 14

ads:
no radiation, dynamic imaging, can see fluid collections, goos at superficial soft tissue imaging

disads:
operator dependent, poor deep tissue resolution, limited bone imaging

Question 15

what is nuclear imaging?

Answer 15

uses radioisotope labelled drugs that serve to mark areas of high biological activity

e.g. metabolically active bone can ben lit up and seen on images - healing fracture areas, osteomyelitis, metastic bone