Background:
Computed tomography (CT) is typically used to measure ileofemoral artery size in patients considered for transcatheter aortic valve replacement (TAVR). However, these patients often have significant arterial calcification, which can introduce artifacts and limit measurement accuracy. We hypothesized that improved iterative reconstruction would improve image quality and reduce artifacts, resulting in larger measured size.
Methods:
We examined 56 patients undergoing CT for possible TAVR, and compared image quality and ileofemoral arterial size between separate reconstructions of the same studies, comparing standard (STD) advanced statistical iterative reconstruction and improved model-based iterative reconstruction (MBIR). A blinded reader identified the sites with the smallest luminal diameter, and provided identical short-axis reformats for both reconstructions. A separate blinded reader graded image quality and made measurements in a random sequence. We compared mean and minimal diameters, image quality (1 poor, 4 excellent), and signal and noise.
Results:
Mean age was 77 ± 10 years and 54% were male. Table 1 compares measured diameters and image quality between STD and MBIR reconstructions. Between STD and MBIR images, ≥moderate beam-hardening artifacts were observed in 30% (17/56) and 9% (5/56) of patients, respectively (p=0.008); severe artifacts were seen in 23% (13/56) and 5% (3/56) of patients, respectively (p=0.01). Overall image quality of STD and MBIR images was graded as good or excellent in 70% (39/56) and 91% (51/56) of cases, respectively (p=0.008).
Conclusion:
In patients referred for TAVR, improved iterative reconstruction resulted in higher image quality, fewer beam-hardening artifacts, and larger measurements of ileofemoral artery size.
A Direct Sinogram Correction Method to Reduce Metal-Related Beam-Hardening in Computed Tomography