13. Special Studies

Question 1

what must you discontinue before an angiogram?

Answer 1

glucophage

(patient may develop metabolic acidosis)

Question 2

what are the phases of a bone scan?

Answer 2

4 phases

1. immediate, early, flow, or angiogram (may be referred to by any of these names)
2. pool
3. delayed
4. fourth phase

Question 3

what is the fourth phase of a bone scan used for?

Answer 3

bone uptake for a patient with PVD

peripheral vascular disease

Question 4

when are the phases of a bone scan imaged?

Answer 4

1. immediate: 2-3 seconds
2. pool: 2-3 minutes
3. delayed: 2-3 hours
4. fourth: 24 hours

Question 5

what does each phase of the bone scan represent?

Answer 5

1. immediate: blood flow
2. pool: soft tissue
3. delayed: bone activity
4. fourth: bone uptake in PVD patient

Question 6

what structures normally light up on a bone scan?

Answer 6

• epiphysis of growing child
• fracture
• tips of scapula
• bladder
• sternum
• intercostals (ribs)

Question 7

what is the half-life of technetium-9?

Answer 7

6 hours

Question 8

what is a likely diagnosis if bone scan lights up in the first and second stages, but not the third?

Answer 8

cellulitis

Question 9

name a way to test between charcot disease and osteomyelitis?

Answer 9

• ceretec scan (tagged wbc)
• indium-111

Question 10

what does gallium-67 test for?

Answer 10

acute inflammation and infection

Question 11

how long does it take for gallium-67 to work?

Answer 11

2-3 days (it’s very expensive)

Question 12

why would you use a technetium and gallium scan together?

Answer 12

Question 13

what cell is tagged with indium-111 test?

Answer 13

white blood cells

(as does the Ceretec scan)

Question 14

why is indium-111 used?

Answer 14

highly sensitive and specific

for acute soft tissue and osseous infection

Question 15

what causes increased signal intensity on T1 MRI image?

Answer 15

fat

Question 16

what causes increased signal intensity on T2 MRI image?

Answer 16

(FIIT)

• fluid
• infection
• inflammation
• tumor

Question 17

for MRI, what are the main indications for STIR imaging?

Answer 17

• edema in high lipid regions (ie bone marrow)
• cartilage evaluation

Question 18

what is fat-saturated MRI used for?

Answer 18

evaluation of fat

Question 19

what is “gradient echo” also known as?

Answer 19

steady state magnetization

Question 20

what is gradient echo used for?

Answer 20

joint imaging

Question 21

what are two uses for gadolinium?

Answer 21

• intravenous: quickly distributed into ECF; distributed to places with increased vascularity, such as neoplasms and inflammation; cellulitis and walls of abscesses will enhance, pus will not
• intra-articular: tests cartilage integrity

Question 22

how will a stress fracture appear on each MRI image?

Answer 22

• T1: linear zone of decreased signal intensity surrounded by a less defined area of signal intensity
• T2: linear zone of decreased signal intensity surrounded by an increased SI due to edema
• STIR: increased SI because fatty bone marrow is suppressed

Question 23

how will osteomyelitis show up on MRI?

Answer 23

• T1: break in cortex, decreased signal intensity in bone marrow
• T2: break in cortex, increased signal in bone marrow

Question 24

how will avascular necrosis appear on MRI?

Answer 24

• decreased signal intensities on T1 and T2
• double rim sign on STIR and long T2 (inner margin will show increased SI, as granulation tissue; outer margin will show decreased SI, as mineralization)

Question 25

what does MRA stand for?

Answer 25

magnetic resonance angiography

Question 26

what is MRA used for in the lower extremity?

Answer 26

• PVD
• DVT
• neoplasm
• anatomic studies

Question 27

what are the three planes of a CT scan?

Answer 27

coronal, axial, sagittal

Question 28

which of the three CT planes is computer reconstructed?

Answer 28

sagittal plane

Question 29

what does the coronal plane of a CT scan represent?

Answer 29

frontal plane

Question 30

what does the axial plane or a CT scan represent?

Answer 30

transverse plane

Question 31

what are some tests for sickle cell anemia?

Answer 31

• microscope and observe
• hemoglobin electrophoresis

Question 32

how many phases are in a ceretec scan?

Answer 32

one

Question 33

what does HMPAO stand for?

Answer 33

hexylmethyl propylene amine oxime (it is ceretec scan)

Question 34

what does MDP stand for?

Answer 34

methyldiphosphate