Which imaging features help differentiate acute ischemic stroke from hemorrhagic stroke in the hyperacute setting?

Which imaging features help differentiate acute ischemic stroke from hemorrhagic stroke in the hyperacute setting?

• A. Non-contrast CT: hemorrhage is hyperdense; ischemia may be subtle or normal; diffusion MRI shows restricted diffusion in acute ischemia; CTA may show vessel occlusion.
• B. Ultrasound cannot differentiate between stroke types.
• C. MRI T2 shows hyperintense hemorrhage.
• D. CTA cannot detect vessel occlusions.

Answer: (A)

In the hyperacute setting, the aim is to rapidly confirm whether bleeding is present and to detect early ischemia plus identify any large-vessel occlusion. Non-contrast CT quickly rules out hemorrhage by looking for a hyperdense bleed; if a hemorrhage is present, it appears bright on CT. However, the absence of a hemorrhage on CT doesn’t rule out stroke, because early ischemia may be subtle or not yet visible on CT. Diffusion-weighted MRI is highly sensitive for acute ischemia and shows restricted diffusion within minutes of onset, reflecting cytotoxic swelling from oxygen deprivation. CT angiography adds the ability to visualize arterial occlusions, which not only supports an ischemic diagnosis but also helps guide treatment decisions such as thrombectomy. Other statements don’t fit in hyperacute practice: ultrasound can assess vessels but cannot definitively distinguish hemorrhagic from ischemic stroke in the hyperacute window; MRI T2 signal alone is not a reliable indicator of acute hemorrhage; and CTA can indeed detect vessel occlusions, so saying it cannot would be incorrect.

In the hyperacute setting, the aim is to rapidly confirm whether bleeding is present and to detect early ischemia plus identify any large-vessel occlusion. Non-contrast CT quickly rules out hemorrhage by looking for a hyperdense bleed; if a hemorrhage is present, it appears bright on CT. However, the absence of a hemorrhage on CT doesn’t rule out stroke, because early ischemia may be subtle or not yet visible on CT.

Diffusion-weighted MRI is highly sensitive for acute ischemia and shows restricted diffusion within minutes of onset, reflecting cytotoxic swelling from oxygen deprivation. CT angiography adds the ability to visualize arterial occlusions, which not only supports an ischemic diagnosis but also helps guide treatment decisions such as thrombectomy.

Other statements don’t fit in hyperacute practice: ultrasound can assess vessels but cannot definitively distinguish hemorrhagic from ischemic stroke in the hyperacute window; MRI T2 signal alone is not a reliable indicator of acute hemorrhage; and CTA can indeed detect vessel occlusions, so saying it cannot would be incorrect.