title: Lateral ventricle morphology analysis via mean latitude axis.
abstract: Statistical shape analysis has emerged as an insightful method for evaluating brain structures in neuroimaging studies, however most shape frameworks are surface based and thus directly depend on the quality of surface alignment. In contrast, medial descriptions employ thickness information as alignment-independent shape metric. We propose a joint framework that computes local medial thickness information via a mean latitude axis from the well-known spherical harmonic (SPHARM-PDM) shape framework. In this work, we applied SPHARM derived medial representations to the morphological analysis of lateral ventricles in neonates. Mild ventriculomegaly (MVM) subjects are compared to healthy controls to highlight the potential of the methodology. Lateral ventricles were obtained from MRI scans of neonates (9-144 days of age) from 30 MVM subjects as well as age- and sex-matched normal controls (60 total). SPHARM-PDM shape analysis was extended to compute a mean latitude axis directly from the spherical parameterization. Local thickness and area was straightforwardly determined. MVM and healthy controls were compared using local MANOVA and compared with the traditional SPHARM-PDM analysis. Both surface and mean latitude axis findings differentiate successfully MVM and healthy lateral ventricle morphology. Lateral ventricles in MVM neonates show enlarged shapes in tail and head. Mean latitude axis is able to find significant differences all along the lateral ventricle shape, demonstrating that local thickness analysis provides significant insight over traditional SPHARM-PDM. This study is the first to precisely quantify 3D lateral ventricle morphology in MVM neonates using shape analysis.
authors.affiliation: Department of Psychiatry, University of North Carolina at Chapel Hill.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Paniagua
authors.forename: Amanda
authors.initials: A
authors.lastname: Lyall
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Berger
authors.forename: Clement
authors.initials: C
authors.lastname: Vachet
authors.forename: Robert M
authors.initials: RM
authors.lastname: Hamer
authors.forename: Sandra
authors.initials: S
authors.lastname: Woolson
authors.forename: Weili
authors.initials: W
authors.lastname: Lin
authors.forename: John
authors.initials: J
authors.lastname: Gilmore
authors.forename: Martin
authors.initials: M
authors.lastname: Styner
keywords: Statistical shape analysis; lateral ventricles; magnetic resonance image biomarkers; mild ventriculomegaly; pediatric imaging