title: Statistical estimation of T1 relaxation times using conventional magnetic resonance imaging.
abstract: Quantitative T1 maps estimate T1 relaxation times and can be used to assess diffuse tissue abnormalities within normal-appearing tissue. T1 maps are popular for studying the progression and treatment of multiple sclerosis (MS). However, their inclusion in standard imaging protocols remains limited due to the additional scanning time and expert calibration required and susceptibility to bias and noise. Here, we propose a new method of estimating T1 maps using four conventional MR images, which are intensity-normalized using cerebellar gray matter as a reference tissue and related to T1 using a smooth regression model. Using cross-validation, we generate statistical T1 maps for 61 subjects with MS. The statistical maps are less noisy than the acquired maps and show similar reproducibility. Tests of group differences in normal-appearing white matter across MS subtypes give similar results using both methods.
authors.affiliation: Department of Biostatistics, The Johns Hopkins University, Baltimore, MD 21205, USA.
authors.forename: Amanda F
authors.initials: AF
authors.lastname: Mejia
authors.affiliation: Department of Biostatistics, The Johns Hopkins University, Baltimore, MD 21205, USA; Translational Neuroradiology Unit, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Sweeney
authors.affiliation: Translational Neuroradiology Unit, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Blake
authors.initials: B
authors.lastname: Dewey
authors.affiliation: Translational Neuroradiology Unit, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Govind
authors.initials: G
authors.lastname: Nair
authors.affiliation: Translational Neuroradiology Unit, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Pascal
authors.initials: P
authors.lastname: Sati
authors.affiliation: Translational Neuroradiology Unit, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Colin
authors.initials: C
authors.lastname: Shea
authors.affiliation: Department of Biostatistics, The Johns Hopkins University, Baltimore, MD 21205, USA; Translational Neuroradiology Unit, Division of Neuroimmunology and Neurovirology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Reich
authors.affiliation: Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA. Electronic address: rshi@upenn.edu.
authors.forename: Russell T
authors.initials: RT
authors.lastname: Shinohara
mesh_terms: D000328:Adult; D000465:Algorithms; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology; D003198:Computer Simulation; D003627:Data Interpretation, Statistical; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009103:Multiple Sclerosis / Q000000981:diagnostic imaging* / Q000473:pathology; D012044:Regression Analysis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D066127:White Matter / Q000000981:diagnostic imaging* / Q000473:pathology
keywords: Image synthesis; Magnetic resonance imaging; Multiple sclerosis; T1 relaxation time