title: Postmortem validation of MRI cortical volume measurements in MS.
abstract: Grey matter (GM) atrophy is a prominent aspect of multiple sclerosis pathology and an important outcome in studies. GM atrophy measurement requires accurate GM segmentation. Several methods are used in vivo for measuring GM volumes in MS, but assessing their validity in vivo remains challenging. In this postmortem study, we evaluated the correlation between postmortem MRI cortical volume or thickness and the cortical thickness measured on histological sections. Sixteen MS brains were scanned in situ using 3DT1-weighted MRI and these images were used to measure regional cortical volume using FSL-SIENAX, FreeSurfer, and SPM, and regional cortical thickness using FreeSurfer. Subsequently, cortical thickness was measured histologically in 5 systematically sampled cortical areas. Linear regression analyses were used to evaluate the relation between MRI regional cortical volume or thickness and histological cortical thickness to determine which postprocessing technique was most valid. After correction for multiple comparisons, we observed a significant correlation with the histological cortical thickness for FSL-SIENAX cortical volume with manual editing (std. β = 0.345, adjusted R(2)  = 0.105, P = 0.005), and FreeSurfer cortical volume with manual editing (std. β = 0.379, adjusted R(2)  = 0.129, P = 0.003). In addition, there was a significant correlation between FreeSurfer cortical thickness with manual editing and histological cortical thickness (std. β = 0.381, adjusted R(2)  = 0.130, P = 0.003). The results support the use of FSL-SIENAX and FreeSurfer in cases of severe MS pathology. Interestingly none of the methods were significant in automated mode, which supports the use of manual editing to improve the automated segmentation. Hum Brain Mapp 37:2223-2233, 2016. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Veronica
authors.initials: V
authors.lastname: Popescu
authors.affiliation: Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Roel
authors.initials: R
authors.lastname: Klaver
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Adriaan
authors.initials: A
authors.lastname: Versteeg
authors.affiliation: Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Pieter
authors.initials: P
authors.lastname: Voorn
authors.affiliation: Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jos W R
authors.initials: JW
authors.lastname: Twisk
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Frederik
authors.initials: F
authors.lastname: Barkhof
authors.affiliation: Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Jeroen J G
authors.initials: JJ
authors.lastname: Geurts
authors.affiliation: Department of Radiology and Nuclear Medicine, VU University Medical Center, Amsterdam, The Netherlands.|Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Hugo
authors.initials: H
authors.lastname: Vrenken
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002540:Cerebral Cortex / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D066128:Gray Matter / Q000000981:diagnostic imaging / Q000473:pathology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000000981:diagnostic imaging* / Q000473:pathology*; D009929:Organ Size; D012984:Software
keywords: FSL-SIENAX; FreeSurfer; SIENAX; SPM; brain atrophy; grey matter; multiple sclerosis