What is the primary purpose of perfusion imaging in acute stroke evaluation?

What is the primary purpose of perfusion imaging in acute stroke evaluation?

• A. Identify tissue at risk (penumbra) to guide therapy decisions.
• B. Measure hematoma size.
• C. Assess bone density.
• D. Evaluate blood glucose.

Answer: (A)

Perfusion imaging is used to map blood flow in the brain to find tissue that is still salvageable but at risk of infarction—the penumbra. By measuring parameters like cerebral blood flow, cerebral blood volume, and mean transit time, clinicians can see areas with reduced blood flow that have not yet suffered irreversible damage. A portion of that hypoperfused tissue can be saved if blood flow is restored promptly, while areas with very low blood volume typically represent already dead tissue (the core). This mismatch between the at-risk tissue and the irreversibly damaged core helps guide decisions about reperfusion therapy, such as whether a patient is a good candidate for thrombolysis or thrombectomy, and even to extend treatment windows when sufficient penumbra is present. Hematoma size, bone density, and blood glucose are assessed with other imaging techniques or tests and are not the purpose of perfusion imaging.

Perfusion imaging is used to map blood flow in the brain to find tissue that is still salvageable but at risk of infarction—the penumbra. By measuring parameters like cerebral blood flow, cerebral blood volume, and mean transit time, clinicians can see areas with reduced blood flow that have not yet suffered irreversible damage. A portion of that hypoperfused tissue can be saved if blood flow is restored promptly, while areas with very low blood volume typically represent already dead tissue (the core). This mismatch between the at-risk tissue and the irreversibly damaged core helps guide decisions about reperfusion therapy, such as whether a patient is a good candidate for thrombolysis or thrombectomy, and even to extend treatment windows when sufficient penumbra is present.

Hematoma size, bone density, and blood glucose are assessed with other imaging techniques or tests and are not the purpose of perfusion imaging.