Technology Update Journal of Neuroimaging Vol 15 No 4 October 2005 Haidar et al:Talairach-Based Parcellation Talairach-Based Parcellation of Neonatal Brain Magnetic Resonance Imaging Data: Validation of a New Approach Haissam Haidar, PhD Simon K. Warfield, PhD Janet S. Soul, MD, CM ABSTRACT Background and Purpose. Talairach-based parcellation (TP) of human brain magnetic resonance imaging (MRI) data has been used increasingly in clinical research to make regional measure- ments of brain structures in vivo. Recently, TP has been applied to pediatric research to elucidate the changes in regional brain volumes related to several neurological disorders. However, all freely available tools have been designed to parcellate adult brain MRI data. Parcellation of neonatal MRI data is very chal- lenging owing to the lack of strong signal contrast, variability in signal intensity within tissues, and the small size and thus diffi- culty in identifying small structures used as landmarks for TP. Hence the authors designed and validated a new interactive tool to parcellate brain MRI data from newborns and young infants. Methods. The authors’ tool was developed as part of a postpro- cessing pipeline, which includes registration of multichannel MR images, segmentation, and parcellation of the segmented data. The tool employs user-friendly interactive software to visualize and assign the anatomic landmarks required for parcellation, after which the planes and parcels are generated automatically by the algorithm. The authors then performed 3 sets of valida- tion experiments to test the precision and reliability of their tool. Results. Validation experiments of intra- and interrater reliability on data obtained from newborn and 1-year-old children showed a very high sensitivity of >95% and specificity >99.9%. The authors also showed that rotating and reformatting the orig- inal MRI data results in a statistically significant difference in par- cel volumes, demonstrating the importance of using a tool such as theirs that does not require realignment of the data prior to parcellation. Conclusions. To the authors’ knowledge, the pre- sented approach is the first TP method that has been developed and validated specifically for neonatal brain MRI data. Their ap- proach would also be valuable for the analysis of brain MRI data from older children and adults. Key words: MRI, brain, newborn, infant, parcellation, Talairach. Haidar H, Warfield SK, Soul JS. Talairach-based parcellation of neonatal brain magnetic resonance imaging data: validation of a new approach. J Neuroimaging 2005;15:305-314. DOI: 10.1177/1051228405279041 The development of brain-mapping techniques using 3- dimensional (3D) magnetic resonance imaging (MRI) led to the need for standardized schemes for regional analysis of brain structure over time and between subjects. Differ- ent approaches for parcellating the human brain have been proposed in the literature. 1-4 However, the scheme presented by Talairach and Tournoux 5 in the form of a co- planar stereotactic atlas using anatomical landmarks became the universal coordinate system for the human brain. Developed initially for stereotactic and functional neurosurgery, this atlas continues to be the most popular coordinate system of the brain in numerous modalities Copyright © 2005 by the American Society of Neuroimaging 305 Received December 17, 2004, and in revised form April 4, 2005. Accepted for publication April 8, 2005. From the Department of Neurology, Children’s Hospital and Harvard Medical School, Boston, MA (HH, JSS); Surgical Planning Laboratory, Department of Radiology, Brigham and Women’s Hospital and Harvard Medical School, Boston, MA (HH, JSS); Computational Radiol- ogy Laboratory, Departments of Radiology, Brigham and Women’s Hospital, Children’s Hospital and Harvard Medical School, Boston, MA (SKW). Address correspondence to Janet S. Soul, Department of Neurology, Fegan 11, Boston, MA 02115. E-mail: janet .soul@childrens.harvard.edu.