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Jureerat Thammaroj , M.D. Radiology Department Khon Kaen University

Ischemic

Stroke

80-85%

Stroke major classifications

Hemorrhagic

Stroke 15-20%

The ” Early ischemic sign “

(Subtle hypodense changes ) ---Strictly within the first 6 Hrs. after symptom onset

Purpose in NCCT --- Hemorrhage ?

Vanishing lentiform nucleus maleus margins

due to isodensity (caused by edema) relative

to the surrounding inner and outer capsule [Radiology 1988:168:463-7, AJNR Am J Neuroradiol 1989:10:1215-22,

Stroke 1992:23:20-3]

“loss of insular ribbon” sign [Radiology 1990:176:801-6]

Early Ischemic Signs

Detection -prox. MCA occlusion effecting deep M1 perforators-

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Sensitivity 5-50% , depending on the

population under study [Neuroradiol 1996:17:1743-8 , Stroke 1992:23:317-24]

False – positive mimics caused by high

hematocrit or vessel wall calcifications [AJNR Am J Neuroradiol 1993:14:669-73]

Dense MCA sign

CBF of less than 10 ml/100g of tissue/min

- - - tissue cannot be tolerated beyond a

few minutes before infarction occurs,

CBF between 10 and 20 ml/100gm/min,

--- cell death in minutes to hours

CBF falls at approximately 18 to 20 ml/100g

of tissue/minute --- Neurological dysfunction occurs in a tissue

CBF and Duration Factors

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Subcortical LMCA ischemic Infarction Hemorrhagic infarction

DWI is far superior to NECT and other

routine MRI sequences in the detection of

acute ischemia, with very high sensitivity and specficity (LOE: A)

The gradient-echoMR sequence

can detect microhemorrhage,

both old and new, better than

CT, indicating the pressence of

amyloid angiopathy, hyper

tension , small vascular

malformations, and other

vascular diseases (LOE: strong B)

PENUMBRA PWI –DWI mismatch

Purpose ; to save the salvageable tissue

Stroke time resolution & imaging modalites

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Is it a true stroke?... Stroke mimics approx. 13%

If yes, is it ischemic VS hemorrhagic stroke?

If it is an ischemic stroke, is there any potential hemorrhagic transformation evidence?

Before start Rx

Parenchyma: CT/MRI

Pipe :angio. /US/CTA-V/MRA-V

Perfusion: CT/MRI/SPECT/PET

Penumbra: DWI/PWI mismatch

CBV/MTT mismatch

Stroke Imaging: The “ 4 P’S ”

1. Is there hemorrhage? Unenhanced CT , MRI

(gradient echo/SWI) (parenchyma) 1. Is there intravascular thrombus that can be targeted

for thrombolysis? CTA , MRA (Pipe)

2. Is there a core of critically ischemic irreversibly infarcted tissue (umbra)? DWI,CTP (abn CBV) (Perfusion)

3. Is there a penumbra of severely ischemic but

4. potentially salvageable tissue? , MR&CT perfusion

5. (PWI-DWI / MTT-CBV mismatch)

The “4 Keys and 4 Ps” Application in the imagine evaluation of acute stroke

Brain stem hemorrhage

History : A 33-years old male,

underlying HT in the young

and gout , presented with left

hemiparesis and aphasia

Brain stem

infaction

Parenchyma: CT/MRI

Pipe :angio. /US/CTA-V/MRA-V

Perfusion: CT/MRI/SPECT/PET

Penumbra: DWI/PWI mismatch

CBV/MTT mismatch

Stroke Imaging: The “ 4 P’S ”

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Outline

Stroke Unit Admission

Aspirin administration

4.5

Endovascular

6 0 8 hrs

IA t-PA / IV t-PA

Physiology is Brain

Time IS brain