CT Reconstruction Levels Affect Automated and Reader-Based ASPECTS Ratings in Acute Ischemic Stroke

Area of Science:

• Radiology
• Medical Imaging
• Neurology

Background:

• The Alberta Stroke Program Early CT Score (ASPECTS) is crucial for assessing acute ischemic stroke.
• Different CT image reconstruction algorithms may influence ASPECTS assessment.

Purpose of the Study:

• To evaluate the impact of varying CT image reconstruction algorithms on automated and reader-based ASPECTS in acute stroke patients.
• To compare the performance of commercial software versus human readers across different reconstruction levels.

Main Methods:

• ASPECTS were evaluated using commercial software and four blinded readers (residents and consultants).
• Assessments were performed on CT images from 43 acute stroke patients reconstructed with filtered back projection and two iterative reconstruction (IR) levels.
• Ground truth was established by an expert reviewer.

Main Results:

• Iterative reconstruction (IR) levels significantly affected resident reader performance and internal consistency.
• Commercial software demonstrated more consistent performance across reconstructions compared to residents.
• Both software and consultants showed deviations from ground truth, with minimal deviation at IR strength level 2.

Conclusions:

• CT image postprocessing, specifically reconstruction algorithms, influences ASPECTS assessment in acute stroke.
• Automated software exhibits more robust and consistent performance than human readers, particularly less experienced ones.
• Iterative reconstruction level 2 appears optimal for minimizing deviations from ground truth.