Clinical Validation of a Semi-Automated Software for Maximal Diameter Measurements for Endovascular Repair Follow-up.

Abstract

PURPOSE\nTo compare automated measurements of maximal diameter (Dmax) of abdominal aortic aneurysm (AAA) orthogonal to luminal or outer wall envelope centerline for endovascular repair (EVAR) follow-up.\n\n\nMATERIAL AND METHODS\nEighty-three consecutive patients with AAA treated by EVAR who had at least 1 computed tomography (CT) scan before and 2 CT scans after EVAR with at least 5 months interval were included. Three-dimensional reconstruction of the AAA was achieved with dedicated segmentation software. Performances of automated calculation algorithms of Dmax perpendicular to lumen or outer wall envelope centerlines were then compared to manual measurement of Dmax on double-oblique multiplanar reconstruction (gold standard). Accuracy of automated Dmax measurements at baseline, follow-up, and progression over time was evaluated by calculation of mean error, Bland-Altman plot, and regression models.\n\n\nRESULTS\nDisagreement in Dmax measurements between outer wall envelope algorithm and manual method was insignificant (mean error: baseline, -0.07 ± 1.66 mm, P\xa0= .7; first follow-up, 0.24 ± 1.69 mm, P\xa0= .2; last follow-up, -0.41 ± 2.74 mm, P\xa0= .17); whereas significant discrepancies were found between the luminal algorithm and the manual method (mean error: baseline, -1.24 ± 2.01 mm, P\xa0<\xa0.01; first follow-up, -1.49 ± 3.30 mm, P < .01; last follow-up, -1.78 ± 3.60 mm, P < .01). Dmax progression results were more accurate with AAA outer wall envelope algorithm compared to luminal method (P\xa0= .2).\n\n\nCONCLUSIONS\nAAA outer wall envelope segmentation is recommended to enable automated calculation of Dmax perpendicular to its centerline during EVAR follow-up.