In-Stent Restenosis in Peripheral Arterial Disease: Ultra-High-Resolution Photon-Counting Versus Third-Generation...

Area of Science:

• Medical Imaging
• Radiology
• Cardiovascular Imaging

Background:

• Visualizing peripheral in-stent restenosis (ISR) with energy-integrating detector CT (EID-CT) is limited by spatial resolution and artifacts.
• Photon-counting detector CT (PCD-CT) offers potential improvements in image quality and diagnostic accuracy for cardiovascular applications.
• Comparing the first clinically available PCD-CT with third-generation EID-CT is crucial for understanding advancements in ISR imaging.

Purpose of the Study:

• To compare the imaging performance of the first clinically available PCD-CT against a third-generation dual-source EID-CT for visualizing peripheral in-stent restenosis.
• To evaluate the impact of different slice thicknesses on image quality and accuracy in detecting and quantifying in-stent restenosis.
• To assess subjective image quality and interrater reliability between the two CT technologies.

Main Methods:

• Nylon cylinders mimicking 75% and 95% stenoses were placed within 8-mm diameter stents and filled with contrast medium.
• Phantoms were scanned using PCD-CT (0.2, 0.5, 1.0 mm slice thickness) and EID-CT (0.5, 1.0 mm slice thickness) at matched CT dose indices.
• Quantitative metrics (contrast-to-noise ratio, full width at half maximum) and subjective image quality scores were analyzed.

Main Results:

• PCD-CT at 0.2 mm slice thickness demonstrated the lowest contrast-to-noise ratio but yielded the highest subjective image quality scores.
• Full width at half maximum measurements for lumen size were comparable between PCD-CT and EID-CT, with greater accuracy at 95% stenosis in smaller slice thicknesses.
• Interrater correlation for subjective assessment was good (0.75), with best scores achieved at 0.2 mm slice thickness on PCD-CT.

Conclusions:

• PCD-CT and EID-CT showed similar accuracy in measuring lumen size for 0% and 75% in-stent restenosis.
• For 95% in-stent restenosis, smaller slice thicknesses in both scanners improved accuracy, with PCD-CT at 0.2 mm offering superior subjective image quality.
• PCD-CT holds promise for improved visualization of peripheral in-stent restenosis, particularly at sub-millimeter slice thicknesses.