Quantification of Aortic Valve Calcification in Contrast-Enhanced Computed Tomography

Area of Science:

• Cardiovascular Imaging
• Radiology
• Medical Physics

Background:

• Aortic valve calcification (AVC) quantification is crucial for diagnosing severe aortic stenosis.
• Contrast-enhanced computed tomography (CECT) is increasingly used, but its utility for AVC quantification requires evaluation.
• Standardized protocols are essential for reliable imaging and quantification.

Purpose of the Study:

• To evaluate a method for quantifying AVC using CECT in patients with suspected severe aortic stenosis pre-interventionally.
• To develop and validate a conversion formula for AVC quantification from CECT data.
• To assess the potential of CECT to replace native CT scans for AVC assessment.

Main Methods:

• Sixty-five patients with aortic stenosis underwent both native and CECT scans.
• AVC was semi-automatically quantified using the Agatston score on native scans as a reference.
• A conversion formula was derived using linear regression on CECT data with a specific calcium threshold.

Main Results:

• A conversion formula (691 + 1.83 x AVCCECT) was developed for AVC quantification from CECT.
• The formula demonstrated high agreement and no significant proportional bias in the validation cohort (Bland-Altman, p = 0.055).
• Excellent agreement was confirmed by an intraclass correlation coefficient of 0.915 (p < 0.001) in the validation cohort.

Conclusions:

• Calcium scoring for aortic valve stenosis is valid using CECT.
• The developed conversion factor ensures excellent agreement, making an additional native CT scan unnecessary.
• This approach may reduce patient radiation exposure.