title: Multispectral MRI segmentation of age related white matter changes using a cascade of support vector machines.
abstract: White matter changes (WMC) are the focus of intensive research and have been linked to cognitive impairment and depression in the elderly. Cumbersome manual outlining procedures make research on WMC labor intensive and prone to subjective bias. We present a fast, fully automated method for WMC segmentation using a cascade of reduced support vector machines (SVMs) with active learning. Data of 102 subjects was used in this study. Two MRI sequences (T1-weighted and FLAIR) and masks of manually outlined WMC from each subject were used for the image analysis. The segmentation framework comprises pre-processing, classification (training and core segmentation) and post-processing. After pre-processing, the model was trained on two subjects and tested on the remaining 100 subjects. The effectiveness and robustness of the classification was assessed using the receiver operating curve technique. The cascade of SVMs segmentation framework outputted accurate results with high sensitivity (90%) and specificity (99.5%) values, with the manually outlined WMC as reference. An algorithm for the segmentation of WMC is proposed. This is a completely competitive and fast automatic segmentation framework, capable of using different input sequences, without changes or restrictions of the image analysis algorithm.
authors.affiliation: Department of Neurobiology, Care Sciences and Society, Division of Clinical Geriatrics, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Soheil
authors.initials: S
authors.lastname: Damangir
authors.forename: Amirhossein
authors.initials: A
authors.lastname: Manzouri
authors.forename: Ketil
authors.initials: K
authors.lastname: Oppedal
authors.forename: Stefan
authors.initials: S
authors.lastname: Carlsson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Firbank
authors.forename: Hogne
authors.initials: H
authors.lastname: Sonnesyn
authors.forename: Ole-Bjørn
authors.initials: OB
authors.lastname: Tysnes
authors.forename: John T
authors.initials: JT
authors.lastname: O'Brien
authors.forename: Mona K
authors.initials: MK
authors.lastname: Beyer
authors.forename: Eric
authors.initials: E
authors.lastname: Westman
authors.forename: Dag
authors.initials: D
authors.lastname: Aarsland
authors.forename: Lars-Olof
authors.initials: LO
authors.lastname: Wahlund
authors.forename: Gabriela
authors.initials: G
authors.lastname: Spulber
mesh_terms: D000375:Aging; D001921:Brain / Q000473:pathology*; D003072:Cognition Disorders / Q000209:etiology; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D056784:Leukoencephalopathies / Q000150:complications / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D012372:ROC Curve; D012680:Sensitivity and Specificity; D060388:Support Vector Machine