title: Improved Correlation of Strain Indices with Cognitive Dysfunction with Inclusion of Adventitial Layer with Carotid Plaque.
abstract: Plaque instability may lead to chronic embolization, which in turn may contribute to progressive cognitive decline. Accumulated strain tensor indices over a cardiac cycle within a pulsating carotid plaque may be viable biomarkers for the diagnosis of plaque instability. Using plaque-only carotid artery segmentations, we recently demonstrated that impaired cognitive function correlated significantly with maximum axial and lateral strain indices within a localized region of interest in plaque. Inclusion of the adventitial layer focuses our strain or instability measures on the vessel wall-plaque interface hypothesized to be a region with increased shearing forces and measureable instability. A hierarchical block-matching motion tracking algorithm developed in our laboratory was used to estimate accumulated axial, lateral, and shear strain distribution in plaques identified with the plaque-with-adventitia segmentation. Correlations of strain indices to the Repeatable Battery for the Assessment of Neuropsychological Status Total score were performed and compared with previous results. Overall, correlation coefficients (r) and significance (p) values improved for axial, lateral, and shear strain indices. Shear strain indices, however, demonstrated the largest improvement. The Pearson correlation coefficients for maximum shear strain and cognition improved from the previous plaque-only analyses of -0.432 and -0.345 to -0.795 and -0.717 with the plaque-with-adventitia segmentation for the symptomatic group and for all patients combined, respectively. Our results demonstrate the advantage of including adventitia for ultrasound carotid strain imaging providing improved association to parameters assessing cognitive impairment in patients. This supports theories of the importance of the vessel wall plaque interface in the pathophysiology of embolic disease.
authors.affiliation: Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA.
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Medicine, University of Wisconsin-Madison, Madison School of Medicine and Public Health, WI, USA.
authors.forename: C C
authors.initials: CC
authors.lastname: Mitchell
authors.affiliation: Department of Medical Physics, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA tvarghese@wisc.edu.
authors.forename: T
authors.initials: T
authors.lastname: Varghese
authors.affiliation: Department of Neurology, University of Wisconsin-Madison, Madison School of Medicine and Public Health, WI, USA.
authors.forename: D C
authors.initials: DC
authors.lastname: Jackson
authors.affiliation: Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA.
authors.forename: B G
authors.initials: BG
authors.lastname: Rocque
authors.affiliation: Department of Neurology, University of Wisconsin-Madison, Madison School of Medicine and Public Health, WI, USA.
authors.forename: B P
authors.initials: BP
authors.lastname: Hermann
authors.affiliation: Department of Neurological Surgery, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Dempsey
mesh_terms: D000328:Adult; D063194:Adventitia / Q000000981:diagnostic imaging*; D000368:Aged; D016893:Carotid Stenosis / Q000000981:diagnostic imaging*; D060825:Cognitive Dysfunction / Q000209:etiology*; D054459:Elasticity Imaging Techniques; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests
keywords: carotid plaque; elasticity imaging; motion tracking; strain; vascular cognitive dementia