Purpose: ECG-gated abdominal CT angiography with reconstruction of multiple, temporally
overlapping CT angiography datasets has been proposed for measuring aortic pulsatility. The
purpose of this work is to develop algorithms to segment the aorta from surrounding structures
from CTA datasets across cardiac phases, calculate registered centerlines and measurements of
regional aortic pulsatility in patients with AAA, and to assess the reproducibility of these
Methods: ECG-gated CTA was performed with a temporal resolution of 165 ms, reconstructed
to 1 mm slices ranging at 14 cardiac phase points. Data sets were obtained from 17 patients on
which two such scans were performed 6 to 12 months apart. Automated segmentation, centerline
generation, and registration of centerlines between phases was performed, followed by
calculation of cross-sectional areas and regional and local pulsatility.
Results: Pulsatility calculations for the supraceliac region were very reproducible between
earlier and later scans of the same patient, with average differences less than 1% for pulsatility
values ranging from 2% to 13%. Local radial pulsatilities were also reproducible to within ~1%.
Aneurysm volume changes between scans can also be quantified.
Conclusion: Automated segmentation, centerline generation, and registration of temporally
resolved CTA datasets permit measurements of regional changes in cross-sectional area over the
course of the cardiac cycle (i.e., regional aortic pulsatility). These measurements are
reproducible between scans 6-12 months apart, with differences in aortic areas reflecting both
aneurysm remodeling and changes in blood pressure. Regional pulsatilities ranged from 2 to
13% but were reproducible at the 1% level.