ORIGINAL RESEARCH n NEURORADIOLOGY Radiology: Volume 268: Number 3—September 2013 n radiology.rsna.org 831 Thalamic Atrophy Is Associated with Development of Clinically Definite Multiple Sclerosis 1 Robert Zivadinov, MD, PhD Eva Havrdová, MD, PhD Niels Bergsland, MS Michaela Tyblova, MD Jesper Hagemeier, MS Zdenek Seidl, MD, PhD Michael G. Dwyer, MS Manuela Vaneckova, MD, PhD Jan Krasensky, MSc Ellen Carl, PhD Tomas Kalincik, MD, PhD Dana Horáková, MD, PhD Purpose: To investigate the association between the development of thalamic and cortical atrophy and the conversion to clin- ically definite multiple sclerosis (CDMS) in patients with clinically isolated syndrome (CIS). Materials and Methods: This prospective study was approved by the institutional review board. Informed consent was given by 216 CIS pa- tients, and patients were treated with 30 μg of intramus- cular interferon b1a once a week. They were assessed with a magnetic resonance (MR) imaging examination at baseline, 6 months, 1 year, and 2 years. Patients were evaluated within 4 months of an initial demyelinating event, had two or more brain lesions on MR images, and had two or more oligoclonal bands in cerebrospinal fluid. MR imaging measures of progression included cumulative number and volume of contrast agent–enhanced (CE) new and enlarged T2 lesions, and changes in whole-brain, tissue-specific global, and regional gray matter volumes. Regression and mixed-effect model analyses were used. Results: Over 2 years, 92 of 216 patients (42.6%) converted to CDMS; 122 (56.5%) CIS patients fulfilled McDonald 2005 criteria and 153 (70.8%) fulfilled McDonald 2010 crite- ria for MR imaging dissemination in time and space. The mean time to first relapse was 3.1 months, and mean an- nual relapse rate was 0.46. In mixed-effect model analysis, the lateral ventricle volume (P = .005), accumulation of CE (P = .007), new total T2 (P = .009) and new enlarging T2 lesions (P = .01) increase, and thalamic (P = .009) and whole-brain (P = .019) volume decrease were associ- ated with development of CDMS. In multivariate regres- sion analysis, decrease in thalamic volumes and increase in lateral ventricle volumes (P = .009) were MR imaging variables associated with the development of CDMS. Conclusion: Measurement of thalamic atrophy and increase in ventric- ular size in CIS is associated with CDMS development and should be used in addition to the assessment of new T2 and CE lesions. q RSNA, 2013 Supplemental material: http://radiology.rsna.org/lookup /suppl/doi:10.1148/radiol.13122424/-/DC1 1 From the Department of Neurology, SUNY, Buffalo Neuroimaging Analysis Center, University at Buffalo, 100 High St, Buffalo, NY 14203 (R.Z., N.B., J.H., M.G.D., E.C.); Department of Neurology and Center of Clinical Neuroscience, Charles University in Prague, First Faculty of Medicine and General University Hospital, Prague, Czech Republic (E.H., M.T., D.H.); Melbourne Brain Centre, Department of Medicine, University of Melbourne, Australia (T.K.); Department of Radiology, Charles University in Prague, First Faculty of Medicine and General University Hospital, Prague, Czech Republic (Z.S., MV). Received October 30, 2012; revision requested December 21; revision received January 10, 2013; accepted January 24; final version accepted February 1. Support was provided by Czech Ministries of Education and Health (grant numbers NT13237-4/2012, MSM 0021620849, PRVOUK-P26/LF1/4, RVO-VFN64 165/2012), and Z.S., M.V., and J.K. were sup- ported by a grant from the Czech Ministry of Health (grant number RVO-VFN64165/2012). Address correspondence to R.Z. (e-mail: rzivadinov@bnac.net). q RSNA, 2013 Note: This copy is for your personal non-commercial use only. To order presentation-ready copies for distribution to your colleagues or clients, contact us at www.rsna.org/rsnarights.