Brain Imaging and Behavior

, Volume 6, Issue 2, pp 329–342

Robust detection of traumatic axonal injury in individual mild traumatic brain injury patients: Intersubject variation, change over time and bidirectional changes in anisotropy

  • Michael L. Lipton
  • Namhee Kim
  • Young K. Park
  • Miriam B. Hulkower
  • Tova M. Gardin
  • Keivan Shifteh
  • Mimi Kim
  • Molly E. Zimmerman
  • Richard B. Lipton
  • Craig A. Branch
mTBI SPECIAL ISSUE

DOI: 10.1007/s11682-012-9175-2

Cite this article as:
Lipton, M.L., Kim, N., Park, Y.K. et al. Brain Imaging and Behavior (2012) 6: 329. doi:10.1007/s11682-012-9175-2

Abstract

To identify and characterize otherwise occult inter-individual spatial variation of white matter abnormalities across mild traumatic brain injury (mTBI) patients. After informed consent and in compliance with Health Insurance Portability and Accountability Act (HIPAA), Diffusion tensor imaging (DTI) was performed on a 3.0 T MR scanner in 34 mTBI patients (19 women; 19–64 years old) and 30 healthy control subjects. The patients were imaged within 2 weeks of injury, 3 months after injury, and 6 months after injury. Fractional anisotropy (FA) images were analyzed in each patient. To examine white matter diffusion abnormalities across the entire brain of individual patients, we applied Enhanced Z-score Microstructural Assessment for Pathology (EZ-MAP), a voxelwise analysis optimized for the assessment of individual subjects. Our analysis revealed areas of abnormally low or high FA (voxel-wise P-value < 0.05, cluster-wise P-value < 0.01(corrected for multiple comparisons)). The spatial pattern of white matter FA abnormalities varied among patients. Areas of low FA were consistent with known patterns of traumatic axonal injury. Areas of high FA were most frequently detected in the deep and subcortical white matter of the frontal, parietal, and temporal lobes, and in the anterior portions of the corpus callosum. The number of both abnormally low and high FA voxels changed during follow up. Individual subject assessments reveal unique spatial patterns of white matter abnormalities in each patient, attributable to inter-individual differences in anatomy, vulnerability to injury and mechanism of injury. Implications of high FA remain unclear, but may evidence a compensatory mechanism or plasticity in response to injury, rather than a direct manifestation of brain injury.

Keywords

Mild traumatic brain injury (mTBI)MRIDiffusion tensor imaging (DTI)Traumatic axonal injury (TAI)Image processing and analysis

Abbreviations

CT

Computerized tomography

DTI

Diffusion tensor imaging

EZ

Enhanced Z-score

EZ-MAP

Enhanced Z-score microstructural assessment for pathology

FA

Fractional anisotropy

GCS

Glasgow Coma Scale

GRF

Gaussian Random Field

HIPAA

Health Insurance Portability and Accountability Act

IRB

Institutional Review Board

JHU

Johns Hopkins University

MNI

Montreal Neurological Institute

MR

Magnetic resonance

mTBI

Mild traumatic brain injury

ROC

Receiver operating characteristic

SD

Standard deviation

TAI

Traumatic axonal injury

TBI

Traumatic brain injury

Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • Michael L. Lipton
    • 1
    • 2
    • 3
    • 4
    • 8
  • Namhee Kim
    • 1
    • 2
  • Young K. Park
    • 1
    • 9
  • Miriam B. Hulkower
    • 1
  • Tova M. Gardin
    • 1
    • 8
  • Keivan Shifteh
    • 8
  • Mimi Kim
    • 5
  • Molly E. Zimmerman
    • 6
  • Richard B. Lipton
    • 5
    • 6
  • Craig A. Branch
    • 1
    • 2
    • 7
  1. 1.The Gruss Magnetic Resonance Research CenterAlbert Einstein College of Medicine of Yeshiva UniversityBronxUSA
  2. 2.Department of RadiologyAlbert Einstein College of Medicine of Yeshiva UniversityBronxUSA
  3. 3.Department of Psychiatry & Behavioral SciencesAlbert Einstein College of Medicine of Yeshiva UniversityBronxUSA
  4. 4.The Dominick P Purpura Department of NeuroscienceAlbert Einstein College of Medicine of Yeshiva UniversityBronxUSA
  5. 5.Department of Epidemiology and Population HealthAlbert Einstein College of Medicine of Yeshiva UniversityBronxUSA
  6. 6.The Saul R. Korey Department of NeurologyAlbert Einstein College of Medicine of Yeshiva UniversityBronxUSA
  7. 7.Department of Physiology & BiophysicsAlbert Einstein College of Medicine of Yeshiva UniversityBronxUSA
  8. 8.The Department of RadiologyMontefiore Medical CenterBronxUSA
  9. 9.Hofstra North Shore-LIJ School of Medicine at Hofstra University, North Shore-Long Island Jewish Health SystemManhassetUSA