Enhancing clot composition analysis in acute ischemic stroke with non-contrast spectral CT: A phantom-based study

Area of Science:

• Medical Imaging
• Radiology
• Interventional Neurology

Background:

• Acute ischemic stroke (AIS) is a critical medical emergency requiring timely intervention.
• Mechanical thrombectomy (MT) is the standard treatment for AIS, but its success depends on accurate clot characterization.
• Conventional CT imaging has limitations in differentiating clot compositions, impacting treatment decisions.

Purpose of the Study:

• To evaluate the utility of spectral CT-derived electron density (ED) and effective atomic number (Z-effective) maps for classifying clot compositions in AIS.
• To compare the diagnostic performance of spectral CT parameters against conventional CT and virtual monoenergetic images.

Main Methods:

• A phantom model with various clot analogs in silicone tubes was used.
• Spectral CT scans were acquired using a dual-layer detector system.
• Conventional CT, ED maps, Z-effective maps, and virtual monoenergetic (MonoE) images at different energy levels were generated.

Main Results:

• Electron density (ED) and high-energy (200 keV) MonoE images demonstrated superior clot type discrimination compared to conventional CT and low-energy MonoE (40 keV) or Z-effective maps.
• Higher effect sizes and area-under-curve (AUC) values were observed for ED and high-energy MonoE images.
• Smaller tube diameters and skull-equivalent material reduced the sensitivity and specificity of spectral methods.

Conclusions:

• Spectral CT parameters, particularly ED and high-energy MonoE images, offer enhanced clot characterization for AIS.
• These findings suggest potential improvements in MT treatment planning.
• Further clinical validation is necessary to confirm the diagnostic value of spectral CT in AIS clot assessment.