1. New quantitative analysis of high-field 3T MRI/DTI to assess neonatal brain development 1,2 G Gerig, 2 Pierre Fillard, 2 M Prastawa, 3 W Lin, 1 John Gilmore, Departments of 1 Psychiatry, 2 Computer Science, 3 Radiology University of North Carolina, Chapel Hill,NC 27614, USA, gerig@cs.unc.edu / http://www.cs.unc.edu/~gerig SUMMARY Structural MRI It is feasible to study brain development in unsedated newborns using 3T MRI Study will likely provide a vastly improved understanding of early brain development and its relationship to neuropsychiatric disorders. Novelty: Tissue model for segmentation of myelinated/nonmyel. white matter. Novelty: Use of tractography for complex regions of interest analysis CONCLUSIONS Building of Atlas Template Research: Quantitative MRI to study unsedated newborns at risk for neurodevelopmental disorders. Clinical Study: 120 newborns recruited at UNC, age at MRI about 2 weeks Motivation: Early detection of abnormalities  Possibility for early intervention and therapy. Imaging: High field (3T Siemens Allegra), high resolution (T1 1mm 3, FSE 0.9x0.9x3mm 3 ), high-speed imaging (12’ for T1, FSE and DTI). Preliminary Study: 20 normal neonates (10 males, 10 females) Age 16 ± 4 days Siemens 3T head-only scanner Neonates were fed prior to scanning, swaddled, fitted with ear protection and had their heads fixed in a vac-fix device A pulse oximeter was monitored by a physician or research nurse Most neonates slept during the scan Motion-free scans in 13-15 infants Conte Center: Total of 120 infants T1 3D MPRage 1x1x1 mm3 FSE T2w 1x1x3 mm3 FSE PDw 1x1x3 mm3 Here Text Template MRIwhite matter csf gray matter Tissue Probability Maps NeonateAdult Approach: Atlas-moderated EM segmentation (cf. Leemput and Warfield) Tissue intensity model for white matter (non-myelinated and myelinated wm form bimodal distribution) (cf. Cocosco, Prastawa) Challenge: Very low CNR, heterogeneous tissue, early myelination regions, reverse contrast wm/gm. Standard brain tissue segmentation fails. Preliminary Results UNC Neonate Study Supported by NIH Conte Center MH064065, Neurodevelopmental Disorders Research Center HD 03110 and the Theodore and Vada Stanley Foundation Literature Gilmore JH, Gerig G, Specter B, Charles HC, Wilber JS, Hertzberg BS, Kliewer MA (2001a): Neonatal cerebral ventricle volume: a comparison of 3D ultrasound and magnetic resonance imaging. Ultrasound Med and Biol 27:1143-1146. Huppi PS, Warfield S, Kikinis R, Barnes PD, Zientara GP, Jolesz FA, Tsuji MK, Volpe JJ (1998b): Quantitative magnetic resonance imaging of brain development in premature and normal newborns. Ann Neurol 43: 224-235. Zhai G, Lin W, Wilber K, Gerig G, Gilmore JH (2003): Comparisons of regional white matter fractional anisotrophy in healthy neonates and adults using a 3T head-only scanner. Radiology (in press). Warfield, S., Kaus, M., Jolesz, F., Kikinis, R.: Adaptive template moderated spa-tially varying statistical classification. In Wells, W.M.e.a., ed.: Medical Image Computing and Computer-Assisted Intervention (MICCAI’98). Volume 1496 of LNCS., Springer 1998 Van Leemput, K., Maes, F., Vandermeulen, D., Suetens, P.: Automated model-based tissue classification of MR images of the brain. IEEE Transactions on Medical Imaging 18 (1999) 897–908 Pierre Fillard, John Gilmore, Weili Lin, Guido Gerig, "Quantitative Analysis of White Matter Fiber Properties along Geodesic Paths", MICCAI 2003 Conference, Full Paper, LNCS Springer, Nov. 2003 Guido Gerig, Marcel Prastawa, Weili Lin and John Gilmore, "Assessing Early Brain Development in Neonates by Segmentation of High-Resolution 3T MRI", Short Paper, MICCAI 2003 Conference, LNCS Springer, Nov. 2003 T1-only segmentation white gray csf myelin. early myelinated corticospinal tract hyper- intense motor cortex Conventional ROI Analysis (one axial slice only) Hypothesis: DTI reflects degree of myelination and structure of fiber tracts. Decrease of fractional anisotropy (FA) from interior to the periphery. Higher ADC values compared to a matured brain (adult). Lower FA values compared to adults. DTI reflects degree of axon pruning and myelination. Zhai G, Lin W, Wilber K, Gerig G, Gilmore JH (2003): Comparisons of regional white matter fractional anisotropy in healthy neonates and adults using a 3T head-only scanner. Radiology (in print). New Method: Diffusion along fiber tract via Tractography Tracing of the commissural fiber tracts through the genu in five neonates splenium FA Diffusion Tensor Imaging (DTI) Fractional Anisotropy (FA) along splenium/genu bundles Change of FA along splenium/genu across time Fractional Anisotropy (FA) quickly drops with increasing distance from midsagittal plane Drop off more pronounced in genu than in splenium Comparisum adults, 2yrs olds and neonates FA in neonates significantly lower than in 2 yrs old subjects and adults 2yrs old subjects show similar values as adults adultneonate adultneonate