Ultra-high-resolution Photon-Counting CT for Leaflet-Specific Evaluation of Fibrosis and Calcification in Aortic Stenosis

In prospectively enrolled patients with moderate aortic stenosis, leaflet-specific indexed calcific and fibrotic volumes from photon-counting CT correlate with CMR leaflet mobility, including sex effects.

• Why it matters: Early aortic stenosis progression depends on leaflet-level fibrosis and calcification, but conventional imaging lacks leaflet-specific quantification linked to functional mobility.
• What they did: Moderate AS participants underwent PCD-CT (n=80) and CMR (n=58); calcific and fibrotic volumes were segmented for RCC, LCC, and NCC and indexed to annulus area, then related to CMR leaflet mobility index (LMI).
• The result: Calcification was higher in males (e.g., ICVRCC 15±16 vs 4±7 uL/cm²; p<0.001) and fibrosis higher in females (e.g., IFVLCC 47±18 vs 34±15 uL/cm²; p=0.004), with LMI correlations (e.g., LMIRCC vs ICVRCC rho=-0.64; p<0.001) and higher PCD-CT image quality and distinguishability versus EID-CT.