4- stroke and IR

Question 1

infarction on CT appearance in general

Answer 1

focal hypodense area in cortical, subcortical or deep gray/white matter in watershed or vascular territory

Question 2

infarction on CT appearance

1-6 hrs

Answer 2

loss of gray matter = edema in gray > white and

obscuring gray/white matter contrast
effacement of sulci = INSULAR RIBBON

Question 3

infarction on CT appearance

6 hrs - 4 days

Answer 3

progressive swelling

hypodensity

Question 4

infarction on CT appearance

4-14 days

Answer 4

return to normal density and volume

Question 5

infarction on CT appearance

>14 days

Answer 5

varying degree of hypodensity and volume loss

ventricle and sulci look bigger as volume decr

Question 6

infarction on MRI appearance
acute
T1 vs T2

Answer 6

hypointense (low signal) on T1 = difficult to see

hyperintense (high signal) on spin density and/or T2 weighted and proton density after 8 hrs in vascular distributions

Question 7

infarction on CT appearance
acute
when is mass effect maximal?

Answer 7

24 hrs

Question 8

infarction on CT appearance
subacute (1 wk or older)
T1
T2

Answer 8

low signal on T1
high signal on T2

follows vascular distrib

Question 9

infarction on CT appearance

if you have revasc and BBB breakdown

Answer 9

causes parenchymal enhancement with contrast

Question 10

infarction on CT appearance
old (several weeks to years)
T1
T2

Answer 10

low signal on T1

high signal on T2

Question 11

infarction on CT appearance
old (several weeks to years)
when does mass effect disappear?

Answer 11

mass effect disappears after 1 month

loss of tissue with large infarcts

Question 12

mechanism of perfusion CT

what does perfusion CT measure

Answer 12

1) inject IV contrast into antecubital fossa
2) continuous imaging at 2-4 locations for 1 min

measures blood flow, blood volume, and timing of bolus to reach brain

Question 13

what does perfusion CT help you determine

Answer 13

helps determine whether salvagable brain penumbra for TPA therapy

Question 14

difference btwn TPA vs. no TPA candiate

Answer 14

TPA = incr time to start, time to peak
no TPA = incr time to start, time to peak

TPA = decr blood volume
no TPA = normal or incr blood volume

Question 15

CTA mechanism

what does it identify?

Answer 15

1) inject IV contrast into internal carotid artery
2) thin images to visualize vascular anatomy

identifies site of occlusion, infarct core, collateral flow
determines whether TPA, MERCI, penumbra worked

SEE PG 17-18 showing tip of basilar thrombosis and improvement post TPA & with penumbra

Question 16

understand treatment of acute infarcts

when to give TPA?
when to extennd window?

Answer 16

early intervention = greatest benefit

TPA = 4-5 hrs after onset
extend window in basilar artery thrombosis

Question 17

understand treatment of acute infarcts

Reopro

Answer 17

Gp2b/3a platelet inhib often given with TPA

Question 18

understand treatment of acute infarcts

mechanical thrombectomy

Answer 18

MERCI

penumbra

Question 19

understand treatment of acute infarcts

off label devices in development

Answer 19

ballooons

stents

Question 20

stroke imaging protocol

Answer 20

1) noncon head CT = look for hematoma, hemorrhage, neoplasm, large infarct (contraindicated for antithrombotic)

2) perfusion CT
find amount of blood flow to given area

3) CTA
IV contrast bolus and depict vascular anatomy

Question 21

MR 1hr -10 days of infarcts

Answer 21

bright on diffusion weighted imaging
dark on apparent diffusion coeff maps

swelling and incr signal on FLAIR and T2 weighted scans follow same as swelling and low denisty on CT

Question 22

DWI great for

Answer 22

small infarcts and telling new (bright) from old)