title: White matter hyperintensities segmentation: a new semi-automated method.
abstract: White matter hyperintensities (WMH) are brain areas of increased signal on T2-weighted or fluid-attenuated inverse recovery magnetic resonance imaging (MRI) scans. In this study we present a new semi-automated method to measure WMH load that is based on the segmentation of the intensity histogram of fluid-attenuated inversion recovery images. Thirty patients with mild cognitive impairment with variable WMH load were enrolled. The semi-automated WMH segmentation included removal of non-brain tissue, spatial normalization, removal of cerebellum and brain stem, spatial filtering, thresholding to segment probable WMH, manual editing for correction of false positives and negatives, generation of WMH map, and volumetric estimation of the WMH load. Accuracy was quantitatively evaluated by comparing semi-automated and manual WMH segmentations performed by two independent raters. Differences between the two procedures were assessed using Student's t-tests and similarity was evaluated using linear regression model and Dice similarity coefficient (DSC). The volumes of the manual and semi-automated segmentations did not statistically differ (t-value = -1.79, DF = 29, p = 0.839 for rater 1; t-value = 1.113, DF = 29, p = 0.2749 for rater 2), were highly correlated [R (2) = 0.921, F (1,29) = 155.54, p < 0.0001 for rater 1; R (2) = 0.935, F (1,29) = 402.709, p < 0.0001 for rater 2] and showed a very strong spatial similarity (mean DSC = 0.78, for rater 1 and 0.77 for rater 2). In conclusion, our semi-automated method to measure the load of WMH is highly reliable and could represent a good tool that could be easily implemented in routinely neuroimaging analyses to map clinical consequences of WMH.
authors: Neuropsychiatry Laboratory, Department of Clinical and Behavioral Neurology, Istituto di Ricovero e Cura a Carattere Scientifico Santa Lucia Foundation Rome, Italy.
authors: Mariangela
authors: M
authors: Iorio
authors: Gianfranco
authors: G
authors: Spalletta
authors: Chiara
authors: C
authors: Chiapponi
authors: Giacomo
authors: G
authors: Luccichenti
authors: Claudia
authors: C
authors: Cacciari
authors: Maria D
authors: MD
authors: Orfei
authors: Carlo
authors: C
authors: Caltagirone
authors: Fabrizio
authors: F
authors: Piras
keywords: FLAIR; MCI; MRI; lesion segmentation; white matter hyperintensities