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Tuesday, February 15, 2011

MR stroke protocol



When we compare the findings on T2WI and DWI in time we will notice the following:
  • In the acute phase T2WI will be normal, but in time the infarcted area will become hyperintense.
  • The hyperintensity on T2WI reaches its maximum between 7 and 30 days. After this it starts to fade.
  • DWI is already positive in the acute phase and then becomes more bright with a maximum at 7 days.
  • DWI in brain infarction will be positive for approximately for 3 weeks after onset (in spinal cord infarction DWI is only positive for one week!).
  • ADC will be of low signal intensity with a maximum at 24 hours and then will increase in signal intensity and finally becomes bright in the chronic stage.

Perfusion MR Imaging
Perfusion with MR is comparable to perfusion CT.
A compact bolus of Gd-DTPA is delivered through a power injector.
Multiple echo-planar images are made with a high temporal resolution.
T2* gradient sequences are used to maximize the susceptibility signal changes.

Now we can see that there is a severe mismatch.
Almost the whole left cerebral hemisphere is at risk due to hypoperfusion.
This patient is an ideal candidate for therapy.

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