Aneurysmal sizing after endovascular repair in patients with abdominal aortic aneurysm: interobserver variability of various measurement protocols and its clinical relevance

Abstract

The aim of this study was to determine the variability of various measurement protocols for measurement of abdominal aortic aneurysm (AAA) and the clinical relevance of variability. Three radiologists performed computed tomographic angiography measurements of both the aorta and the largest portion of the aneurysm on selected axial slices. Then measurements of the largest portion of the aneurysm were performed on unselected axial slices, sagittal and coronal reformatted. Finally, aortic volume was calculated. Measurements and volume calculation were performed before and after endovascular repair and assessed: Part 1: interobserver variability for maximum anteroposterior (MAP) and maximum transverse (MTR) diameters on selected slices; part 2: interobserver variability for unselected slices considering MAP and MTR; part 3: interobserver variability considering maximum diameter in any direction (MAD); part 4: interobserver variability for sagittal (SAG) and coronal (COR) free curved multiplanar reformation (MPR); and part 5: volume calculations. We then determined which technique of measurement was the most clinically relevant for detecting changes in aneurysm size or aortic volume. Parts 1 and 2: interobserver variability was 4.1 mm for both MAP and MTR; part 3: interobserver variability was 7 mm for MAD; part 4: interobserver variability was 5.5 mm (COR) and 4.9 mm (SAG); part 5: interobserver variability for volume was 5.5 ml. A combination of MAP and MTR was the most useful for detecting aortic modification. Volume calculation was needed in only a few cases. We recommend avoiding MAD and MPR measurements and suggest instead measuring both maximum anteroposterior and maximum transverse diameters. If aneurysm size remains stable after endovascular repair, aneurysm volume should be measured.

Management of peripheral arterial disease: Role of computed tomography angiography and magnetic resonance angiography

“…This measurement should be taken outer wall to outer wall in lateral and anteroposterior projection. There is still some controversy if measurement should be taken on axial slices or longitudinal reformation perpendicularly to aneurysm central line [70][71][72]. Then CTA will display the relation ship of AAA with renal, mesenteric and celiac arteries and aneurysm extension in iliac arteries.…”

Abdominal aortic aneurysms: virtual imaging and analysis through a remote web server

“…The identification of anatomical contraindications and the selection of the proper stent-graft are of outmost importance to determine early and mid-term outcomes [6][7][8][9]. Vessel diameters can be accurately calculated by magnified digital images perpendicular to the lumen centerline [14][15][16][17], whereas lengths should be calculated either along the centerline of the aortic lumen using CPRs [9,18] or, as proposed by Tillich et al [19], along the shortest aorto-iliac path, to better predict stent-graft length. Finally, angles should be obtained by using 3D reconstructions of the aorta.…”

Hybrid-repair of thoraco-abdominal or juxtarenal aortic aneurysm: what the radiologist should know

“…A curved plane along a predefined data volume is used for creating a curved MPR. Curved MPR can be used for better display of regions of tortuosity, but diameter measurements with this technique are usually highly prone to errors [22]. A semi-automatic centreline analysis allows automatic diameter calculations by generating an optimal track through the centreline of a vascular segment (Fig.…”