MSK imaging

Question 1

radiograph - plain film

Answer 1

cheap
indicated for bones, foreign objects and hardware
generally first line
cons: need multiple views - negligible to very low risk of cancer

Question 2

radiograph- fluoroscopy

Answer 2

indicated for procedures - live action -iodine dye used to confirm accurate injection of structures (high penetration); cons: increase risk due to multiple x rays

Question 3

what is the spectrum of absorption for X-rays

Answer 3

in decreasing density levels;white - high: metal, bone; intermediate: soft tissue ( muscles, fat, fascia); low: air filled organs _ black

Question 4

define radiograph

Answer 4

high frequency/energy electromagnetic waves that penetrate soft tissue (form of ionizing radiation);can produce damage to tissue/DNA (low dose: cancer; high dose: radiation sickness)

Question 5

radiography- digital subtraction angiography

Answer 5

iodine based contrast is injected IV, makes vessels termporarily visible to x rays; image via fluoroscopy- computer subtracts bone; cons: contrast can injure kidneys, radiation from fluoroscopy

Question 6

radiography- DEXA- dual energy x ray absorptiometry

Answer 6

two energy levels x ray beams (compares bone absorption)
indication: bone density scan when concerned for osteoporosis/osteopenia; standard for bone density measurements - cons: ionizing radiation

Question 7

radiography- computer tomography - CT/ CAT scan (computer aided tomography)

Answer 7

numerous XRs as cross sectional slices; 3d saggital and transverse views of the structures; can increase resolution by combining mult. images in a single plane; taking thinner slices, more images closer to each other

Question 8

CT angiography

Answer 8

iodine based contrast used ot improve context between structures (IV) - vasculature/ organs

Question 9

what are iodine (IV) contrast risks

Answer 9

can cause kidney damage and have rare but possible allergic reactions

Question 10

CT indications

Answer 10

visualize boney structures - plain film radiograph can’t see ( OA/AA joint), its high resolution can fing hard to see fractures; soft tissue, other organs such as abdominal organs, brain and blood vessles.

Question 11

what are pros to ct scan

Answer 11

affordable, quick, 3d image with good resolution

Question 12

what are the cons

Answer 12

relative high risk of radiation and iodine contrast can cause kidney damage

Question 13

MRI- magnetic resonance imaging

Answer 13

uses a powerful magnetic field and radiofrequency waves on protons abundant in water and fat, to generate images

Question 14

what are the steps to MRI

Answer 14

1. magnetic field lines up randomly aligned protons; 2. radiofrequency pulse–> changes proton alignment in magnetic field; 3. radiofrequency pulse deactivates–> protons realign with the magnetic field–> release energy which is read by the MRI machine

Question 15

what is the interpretation for MRI/CT

Answer 15

3d (sagittal and transverse views) - common reading convention is the sagittal plane slices

Question 16

MRI indications

Answer 16

excels in visualizing soft tissue structure (cartilage, tendons, etc) = best for joint injury. Can find missed/hard to see structures

Question 17

MRI pros:

Answer 17

no ionizing radiation, highest resolution, can differentiate soft tissue ( ex. tumors )

Question 18

MRI cons:

Answer 18

expensive, slow and time consuming; difficult for claustrophobic pts; cannot use in patients with metal implants

Question 19

ultrasound

Answer 19

uses echolocation to produce image
low frequency - more penetration, lower resolution; higher frequency- less penetration, higher resolution; waves travel into body then reflect back to make a single live 2-d image

Question 20

ultrasound interpretation

Answer 20

hyperechoic/dense - not able to penetrate (bone, metal); anechoic/black - fully penetrates (air, fluid-blood); hypoechoic/dark (organs, soft tissue)

Question 21

ultrasound indications, pros, cons

Answer 21

indication: quick diagnosis and guiding procedures, able to differentiate soft tissue well; pros: cheap, fast, portable, no ionizing radiation; cons: not always available, user dependent, not able to visualize structures behind bone (waves blocked) and bigger anechoic structures (waves scatter)

Question 22

nuclear medicine

Answer 22

used to measure physiology not anatomy - IV injected radiotracers will bind to targeted physiological process- produce high conc. of gamma radiation visualized by camera

Question 23

nuclear medicine-positron emission tomography (PET)

Answer 23

radiotracer is a glucose analog and will aggregate in areas of most glucose storage; indications (cancer monitoring- increased use of glucose); pros: targeted absorption by physio; cons: radiotracers produce ionizing radiation