Abstract 251: Semiautomated Measurement of Ascending Aortic Aneurysm Versus Manual Measurement: Assessment of Variability

Abstract

Purpose: To evaluate inter method and intra observer variability of a novel semi-automated method for measurement of ascending aorta aneurysm (AAA) in ECG gated dual source CT angiogram (DSCTA).

Material and Method: Under an IRB approved protocol, multiplanar reformatted images of 40 patients with AAA were measured in DSCTA images. Transaxial maximum diameter of inner wall to inner wall was measured at five anatomic locations of thoracic aorta: annulus, sinus, sinotubular junction (STJ), mid ascending aorta at the level of right pulmonary artery (MAA), and proximal aortic arch immediately proximal to innominate artery (PROX) (Figure 1). Measurements were performed by conventional manual method and the novel semi-automated segmentation software and compared. Inter method and intra observer variability were evaluated according to Intra Class Correlation (ICC). Time required for post processing of the aorta with both methods was recorded in all the cases.

Results: Mean maximum diameters in semi-automated method were: annulus 31.10 mm, sinus: 41.95 mm, STJ: 38.05 mm, MAA: 41.88 mm, and PROX: 37.60 mm. Manual method showed mean maximum diameter of 30.87 mm, 42.05 mm, 36.87 mm, 41.18 mm, and 36.42 mm at annulus, sinus, STJ, MAA, and PROX, respectively.

There was an excellent inter method and intra observer agreement between two methods at all five points (ICC > 0.9). The post processing time was 8’2’’±1’35” for the semi-automated method while this time was 19’± 20” for the manual method.

Conclusion: The novel semi-automated tool demonstrated an excellent agreement with conventional manual method in measurement of AAA in ECG gated DSCTA with the advantage of significant reduction in the post processing time.