Estimate age of stroke - CT

Hyperacute (<12h)

• Normal (50-60%)
• Hyperdense artery (25-50%)
• Obscuration of lentiform nuclei

Acute (12-24h)

• Low density basal ganglia
• Loss of gray-white interfaces (insular ribbon sign, obscuration of cortex-medullary white matter border)
• Sulcal effacement

1-3days

• Increasing mass effect
• Wedge-shaped low density area that involves both gray and white matter
• Hemorrhagic transformation may occur (most often basal ganglia and cortex)

4-7 days

• Gyral enhancement
• Mass effect, edema persist

1-8 weeks

• Contrast enhancement perists
• Mass effect resolves
• Transient calcification can occur (pediatric strokes)

Months-years

• Encephalomalacic change, volume loss
• Calcification rare