Estimate age of stroke - MRI

Age of stroke on MR (from Diagnostic Neuroradiology by Osborn)

Immediate

• Absence of normal flow void
• Intravascular contrast enhancement
• Diffusion restriction (high DWI/low ADC)
• Perfusion alteration
• High DWI and normal T2/FLAIR is 62% sensitive and 78% specific for stroke <4.5hours old [Lancet Neurology 10/5/2011]

<12h

• Sulcal effacement
• Gyral edema
• Loss of gray-white

12-24h

• Hyperintensity on T2/FLAIR
• Meningeal enhancement adjacent to infarct
• Mass effect

1-3 days

• Intravascular, meningeal enhancement starts to decrease
• Early parenchymal enhancement
• Striking signal abnormality on T1/T2
• Hemorrhagic transformation may be evident

4-7 days

• Striking parenchymal enhancement
• Hemorrhage in 25%
• Mass effect diminishing
• Intravascular, meningeal enhancement disappears

1-8 weeks

• Contrast enhancement often persists
• Restricted diffusion ends at ~10-14 days
• Mass effect resolves
• Decrease in abnormal T2 signal sometimes
• Hemorrhagic changes evolve

Months/Years

• Encephalomalacic changes, volume loss
• Hemosiderin staining if prior hemorrhage