title: A New Approach for Deep Gray Matter Analysis Using Partial-Volume Estimation.
abstract: BACKGROUND
  The existence of partial volume effects in brain MR images makes it challenging to understand physio-pathological alterations underlying signal changes due to pathology across groups of healthy subjects and patients. In this study, we implement a new approach to disentangle gray and white matter alterations in the thalamus and the basal ganglia. The proposed method was applied to a cohort of early multiple sclerosis (MS) patients and healthy subjects to evaluate tissue-specific alterations related to diffuse inflammatory or neurodegenerative processes.
  
  
  METHODS
  Forty-three relapsing-remitting MS patients and nineteen healthy controls underwent 3T MRI including: (i) fluid-attenuated inversion recovery, double inversion recovery, magnetization-prepared gradient echo for lesion count, and (ii) T1 relaxometry. We applied a partial volume estimation algorithm to T1 relaxometry maps to gray and white matter local concentrations as well as T1 values characteristic of gray and white matter in the thalamus and the basal ganglia. Statistical tests were performed to compare groups in terms of both global T1 values, tissue characteristic T1 values, and tissue concentrations.
  
  
  RESULTS
  Significant increases in global T1 values were observed in the thalamus (p = 0.038) and the putamen (p = 0.026) in RRMS patients compared to HC. In the Thalamus, the T1 increase was associated with a significant increase in gray matter characteristic T1 (p = 0.0016) with no significant effect in white matter.
  
  
  CONCLUSIONS
  The presented methodology provides additional information to standard MR signal averaging approaches that holds promise to identify the presence and nature of diffuse pathology in neuro-inflammatory and neurodegenerative diseases.
authors: Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland.|LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.|Department of Clinical Neurosciences, LREN and Neuroimmunology Laboratory, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
authors: Guillaume
authors: G
authors: Bonnier
authors: Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland.|LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.|Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
authors: Tobias
authors: T
authors: Kober
authors: Department of Clinical Neurosciences, LREN and Neuroimmunology Laboratory, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
authors: Myriam
authors: M
authors: Schluep
authors: Department of Clinical Neurosciences, LREN and Neuroimmunology Laboratory, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
authors: Renaud
authors: R
authors: Du Pasquier
authors: Siemens Medical Solutions USA IM MR COL NEZ, Burlington, MA, United States of America.
authors: Gunnar
authors: G
authors: Krueger
authors: Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
authors: Reto
authors: R
authors: Meuli
authors: Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland.|LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.|Department of Clinical Neurosciences, LREN and Neuroimmunology Laboratory, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.
authors: Cristina
authors: C
authors: Granziera
authors: Department of Radiology, Centre Hospitalier Universitaire Vaudois (CHUV), Lausanne, Switzerland.|Advanced Clinical Imaging Technology, Siemens Healthcare IM BM PI, Lausanne, Switzerland.|LTS5, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.
authors: Alexis
authors: A
authors: Roche
mesh_terms: D000328:Adult; D001479:Basal Ganglia / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000175:diagnosis*; D013788:Thalamus / Q000473:pathology; D066127:White Matter / Q000473:pathology; D055815:Young Adult