title: True four-dimensional analysis of thoracic aortic displacement and distension using model-based segmentation of computed tomography angiography.
abstract: Previous analyses of aortic displacement and distension using computed tomography angiography (CTA) were performed on double-oblique multi-planar reformations and did not consider through-plane motion. The aim of this study was to overcome this limitation by using a novel computational approach for the assessment of thoracic aortic displacement and distension in their true four-dimensional extent. Vessel segmentation with landmark tracking was executed on CTA of 24 patients without evidence of aortic disease. Distension magnitudes and maximum displacement vectors (MDV) including their direction were analyzed at 5 aortic locations: left coronary artery (COR), mid-ascending aorta (ASC), brachiocephalic trunk (BCT), left subclavian artery (LSA), descending aorta (DES). Distension was highest for COR (2.3 ± 1.2 mm) and BCT (1.7 ± 1.1 mm) compared with ASC, LSA, and DES (p < 0.005). MDV decreased from COR to LSA (p < 0.005) and was highest for COR (6.2 ± 2.0 mm) and ASC (3.8 ± 1.9 mm). Displacement was directed towards left and anterior at COR and ASC. Craniocaudal displacement at COR and ASC was 1.3 ± 0.8 and 0.3 ± 0.3 mm. At BCT, LSA, and DES no predominant displacement direction was observable. Vessel displacement and wall distension are highest in the ascending aorta, and ascending aortic displacement is primarily directed towards left and anterior. Craniocaudal displacement remains low even close to the left cardiac ventricle.
authors.affiliation: Diagnostic and Interventional Radiology, University Medical Center Heidelberg, INF 110, 69120, Heidelberg, Germany, tim.weber@med.uni-heidelberg.de.
authors.forename: Tim F
authors.initials: TF
authors.lastname: Weber
authors.forename: Tobias
authors.initials: T
authors.lastname: Müller
authors.forename: Andreas
authors.initials: A
authors.lastname: Biesdorf
authors.forename: Stefan
authors.initials: S
authors.lastname: Wörz
authors.forename: Fabian
authors.initials: F
authors.lastname: Rengier
authors.forename: Tobias
authors.initials: T
authors.lastname: Heye
authors.forename: Tim
authors.initials: T
authors.lastname: Holland-Letz
authors.forename: Karl
authors.initials: K
authors.lastname: Rohr
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Kauczor
authors.forename: Hendrik
authors.initials: H
authors.lastname: von Tengg-Kobligk
mesh_terms: D059925:Anatomic Landmarks; D001013:Aorta, Thoracic / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001018:Aortic Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D001027:Aortography / Q000379:methods*; D056973:Four-Dimensional Computed Tomography; D006801:Humans; D008955:Models, Cardiovascular; D061330:Multidetector Computed Tomography; D011237:Predictive Value of Tests; D011673:Pulsatile Flow; D011857:Radiographic Image Interpretation, Computer-Assisted; D012039:Regional Blood Flow; D012189:Retrospective Studies; D016277:Ventricular Function, Left