Aortic volume as an indicator of disease progression in @entity1 with untreated XXXX .

@entity1 @entity439 @entity1028
OBJECTIVE: The maximal diameter of an @entity1028 ( @entity1028 ) and the change in diameter over time reflect rupture risk and are used for surgical planning. However, evidence has emerged that @entity439 volume may be a better indicator of @entity1028 remodeling. The purpose of this study was to assess the relationship between the volume and maximal diameter of the abdominal aorta in @entity1 with untreated @entity1028 . MATERIALS AND METHODS: This was a retrospective study of 100 @entity1 with @entity1028 who were followed for more than 6 months. We examined 2 sets of computed tomography images for each @entity1 , acquired >=  6 months apart. The maximal diameter and volume of the infrarenal abdominal aorta were determined by semiautomated segmentation software. RESULTS: At baseline, mean maximal infrarenal diameter was 5.1    1.0 cm and mean aortic volume was 139    72 mL. There was good correlation between the maximal diameter and aortic volume at baseline (r(2) = 0.55; P<0.001). The mean change in maximal diameter between studies was 0.2    0.3 cm and the mean volume change was 19    19 mL. However, the correlation between diameter change and volume change was modest (r(2) = 0.34; P=0.001). Most @entity1 (n = 64) had no measurable change in maximal diameter between studies ( <= 2 mm), but the change in volume was found to vary widely (-2 to 69 mL). CONCLUSION: In @entity1 with untreated @entity1028 , a change in aortic volume can occur in the absence of a significant change in maximal diameter. Additional work is needed to examine the relationship between change in @entity1028 volume and outcomes in this @entity1 group.
