Atherosclerotic Plaque Burden on Abdominal CT: Automated Assessment With Deep Learning on Noncontrast and Contrast-enhanced Scans

Background: Abdominal aortic atherosclerotic plaque burden may have clinical significance but manual measurement is time-consuming and impractical. Purpose: To perform external validation on an automated atherosclerotic plaque detector for noncontrast and postcontrast abdominal CT. Materials and Methods: The training data consisted of 114 noncontrast CT scans and 23 postcontrast CT urography scans. The testing data set consisted of 922 CT colonography (CTC) scans, and 1207 paired noncontrast and postcontrast CT scans from renal donors from a second institution. Reference standard data included manual plaque segmentations in the 137 training scans and manual plaque burden measurements in the 922 CTC scans. The total Agatston score and group (0-3) was determined using fully-automated deep learning software. Performance was assessed by measures of agreement, linear regression, and paired evaluations. Results: On CTC scans, automated Agatston scoring correlated highly with manual assessment (R-2 = 0.94). On paired renal donor CT scans, automated Agatston scoring on postcontrast CT correlated highly with noncontrast CT (R-2 = 0.95). When plaque burden was expressed as a group score, there was excellent agreement for both the CTC (weighted kappa 0.80 +/- 0.01 [95% confidence interval: 0.78-0.83]) and renal donor (0.83 +/- 0.02 [0.79-0.86]) assessments. Conclusion: Fully automated detection, segmentation, and scoring of abdominal aortic atherosclerotic plaques on both pre- and postcontrast CT was validated and may have application for population-based studies.

Automated summary

The study validates the feasibility of fully automated detection, segmentation, and scoring of abdominal aortic atherosclerotic plaques on both noncontrast and postcontrast CT scans. Through linear regression and paired evaluations, it was found that automated Agatston scoring correlates highly with manual assessment in CTC scans and renal donor CT scans.