Hypodensity Beyond the Ischemic Core: Penumbral Changes Detected With Relative Noncontrast Computed Tomography

Area of Science:

• Neurology
• Radiology
• Medical Imaging

Background:

• Acute ischemic stroke leads to infarcted tissue detectable on noncontrast computed tomography (NCCT) as hypodensity.
• This study investigated subtle NCCT density changes in penumbral tissue, beyond the core infarct.

Purpose of the Study:

• To determine if penumbral tissue in acute ischemic stroke exhibits detectable density changes on NCCT.
• To assess the correlation between penumbral hypodensity, hypoperfusion severity, and 90-day functional outcomes.

Main Methods:

• Observational cohort study of patients with anterior circulation occlusions.
• Analysis of relative NCCT images comparing voxel density to the contralateral hemisphere.
• Correlation of penumbral relative density with computed tomography perfusion parameters and 90-day functional outcomes.

Main Results:

• A median relative hypodensity of 1.8% was observed in the penumbra (P<0.0001).
• Penumbra hypodensity increased with greater hypoperfusion severity (time-to-maximum).
• A trend towards worse functional outcomes was associated with more hypodense penumbra.

Conclusions:

• Relative hypodensity is identifiable in the penumbra of acute ischemic stroke patients using NCCT.
• Penumbra hypodensity on NCCT shows potential clinical relevance for predicting 90-day functional outcomes.
• The degree of hypodensity correlates with the severity of hypoperfusion.