Neonatal Brain Development assessed by new quantitative Analysis of 3Tesla MRI and DTI

1
Neonatal Brain Development assessed by new
quantitative Analysis of 3-Tesla MRI and DTI 1,2G
Gerig, 2Pierre Fillard, 2M Prastawa, 3W Lin,
1John Gilmore, Departments of 1Psychiatry,
2Computer Science, 3Radiology University of North
Carolina, Chapel Hill,NC 27614, USA,
gerig_at_cs.unc.edu / http//www.cs.unc.edu/gerig
Diffusion Tensor Imaging (DTI)
SUMMARY

• Research Quantitative MRI to study unsedated
  newborns at risk for neurodevelopmental
  disorders.
• Clinical Study 120 newborns to e brecruited 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 1mm3, FSE 0.9x0.9x3mm3),
  high-speed imaging (12 for T1, FSE and DTI).

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).
Neonate
Adult
New Method Diffusion along fiber tract via
Tractography

• Challenge Very low CNR, heterogeneous tissue,
  early myelination regions, reverse contrast
  wm/gm.
• Standard brain tissue segmentation fails.

Tracing of the commissural fiber tracts through
the genu in five neonates
T1 3D MPRage 1x1x1 mm3
FSE T2w 1x1x3 mm3
FSE PDw 1x1x3 mm3
Structural MRI
splenium

• 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)

Fractional Anisotropy (FA) along splenium/genu
bundles
FA
FA

• Fractional Anisotropy (FA) quickly drops with
  increasing distance from midsagittal plane
• Drop off more pronounced in genu than in splenium

Building of Atlas Template
Change of FA along splenium/genu across time

• 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

T1-only segmentation
CONCLUSIONS

• 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.

hyper- intense motor cortex
early myelinated corticospinal tract
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 271143-1146.
• 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) Comparison of regional white matter
  fractional anisotrophy in healthy neonates and
  adults using a 3T head-only scanner. Radiology
  229, 2003, pp. 673-681
• 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 (MICCAI98).
  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) 897908
  
• Pierre Fillard, John Gilmore, Weili Lin, Guido
  Gerig, "Quantitative Analysis of White Matter
  Fiber Properties along Geodesic Paths", Lecture
  Notes in Computer Science LNCS 2879 Springer,
  Nov. 2003, pp. 16-23
• Guido Gerig, Marcel Prastawa, Weili Lin and John
  Gilmore, "Assessing Early Brain Development in
  Neonates by Segmentation of
  High-Resolution 3T MRI", LNCS 2879, Springer,
  Nov. 2003,

Preliminary Results UNC Neonate Study

• 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

Supported by NIH Conte Center MH064065,
Neurodevelopmental Disorders Research Center HD
03110 and the Theodore and Vada Stanley
Foundation.