title: Automatic carotid artery distensibility measurements from CTA using nonrigid registration.
abstract: The distensibility of a blood vessel is a marker of atherosclerotic disease. In this paper we investigate the feasibility of measuring carotid artery distensibility on 4D CTA, both manually and using a new automatic method. On 4D CTA datasets manual (n=38) and automatic (n=76) measurements of the carotid distensibility were performed. A subset (n=10) of the manual annotations were repeated by a second observer. The interobserver variability was assessed using a Bland-Altman analysis and appeared to be too large to reliably measure the distensibility using manual annotation. We compared two versions of the automatic method: one using 3D registration and one using a 4D registration method. The latter resulted in a more smooth deformation over time. The automatic method was evaluated using a synthetic deformation and by investigating whether known relations with cardiovascular risk factors could be reproduced. The relation between distensibility and cardiovascular risk factors was tested with a Mann-Whitney U test. Automatic measurements revealed an association with hypertension whereas the manual measurements did not. This relation has been found by other studies too. We conclude that carotid artery distensibility measurements should be performed automatically and that the method described in this paper is suitable for that. All CTA datasets and related clinical data used in this study can be downloaded from our website (http://ctadist.bigr.nl).
authors.affiliation: Biomedical Imaging Group Rotterdam, Departments of Radiology & Medical Informatics, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands. K.Hameeteman@Erasmusmc.nl
authors.forename: K
authors.initials: K
authors.lastname: Hameeteman
authors.forename: S
authors.initials: S
authors.lastname: Rozie
authors.forename: C T
authors.initials: CT
authors.lastname: Metz
authors.forename: R
authors.initials: R
authors.lastname: Manniesing
authors.forename: T
authors.initials: T
authors.lastname: van Walsum
authors.forename: A
authors.initials: A
authors.lastname: van der Lugt
authors.forename: W J
authors.initials: WJ
authors.lastname: Niessen
authors.forename: S
authors.initials: S
authors.lastname: Klein
mesh_terms: D000368:Aged; D000792:Angiography / Q000379:methods*; D002339:Carotid Arteries / Q000000981:diagnostic imaging*; D002340:Carotid Artery Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D055119:Elastic Modulus; D005240:Feasibility Studies; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D006801:Humans; D008297:Male; D010363:Pattern Recognition, Automated / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D014655:Vascular Resistance