AJR 2000; 175:1279-1282
Wever J.J., Blankensteijn J.D., van Rijn J.C., Broeders I.A.M.J., Eikelboom B.C., Mali W.P.Th.M.
OBJECTIVE: Important decisions are made on the basis of CT angiographic measurements of aneurysm size obtained after endovascular abdominal aortic aneurysm repair; however, little is known about the variability of these measurements. We evaluated the variability of CT angiographic measurements of aneurysm size obtained after endovascular abdominal aortic aneurysm repair.
MATERIALS AND METHODS: Thirty CT angiographic data sets were randomly chosen from 91 sets, including preoperative, postoperative, and follow-up CT images. All images were obtained according to a standardized acquisition protocol. On a workstation, three parameters were measured: maximum aneurysm diameter, maximum aneurysm cross-sectional area, and aneurysm volume. All data sets were measured twice by two investigators in a random order. The difference of each pair of measurements was plotted against the mean value. The mean difference and its standard deviation were calculated with a repeatability coefficient.
RESULTS: The intraobserver repeatability coefficient for observer 1 was 3.8 mm for diameter, 201.7 mm2 for cross-sectional area, and 5.6 mL for volume. For observer 2, these figures were 3.0 mm, 219.0 mm2 , and 8.1 mL respectively. The interobserver repeatability coefficients were 3.9 mm, 236.2 mm2 , and 10.3 mL.
CONCLUSION: Determination of the repeatability coefficient of aneurysm size measurements obtained after endovascular abdominal aortic aneurysm repair provides a good description of precision.