Page 101 - NNS 2014 Program & Abstract Book

tained at 12.2 – 3.5 months. NAA/Cr and NAA/Cho ratios were sig-
nificantly reduced in severely injured patients compared to controls
and mildly injured patients in all regions. Furthermore, NAA/Cr ratios
were significantly different between all severity levels in frontal and
temporal gray matter regions, and correlated with FSIQ, Memory
Score and PCPCS from most regions. Only NAA/Cr from white
matter regions correlated with the Attention score. Mean FA and AD
were significantly reduced in severely injured compared to controls in
basal ganglia, corpus callosum, and white matter regions and corre-
lated with FSIQ and General Memory scores.
Early neuronal loss/dysfunction and axonal disruption correlate
with long term intellectual and memory deficits. White matter injury
may be more predictive of attention deficits. Support from NIH/
NINDS:R01-NS054001
Key words
diffusion tensor imaging, magnetic resonance spectroscopy, neu-
ropsychologic testing, pediatric, traumatic brain injury
B4-28
LONGITUDINAL TRACT-BASED ANALYSIS OF CALLOSAL
DISRUPTION IN MODERATE/SEVERE PEDIATRIC TRAU-
MATIC BRAIN INJURY
Dennis, E.L.1, Jin, Y.1 , Villalon-Reina, J.E.1, Kernan, C.L.2, Mink,
R.B.3, Babikian, T.2, Giza, C.C.4 , Asarnow, R.F.2 , Thompson, P.M.1,2
1IGC, INI, USC, Los Angeles, USA
2Dept. of Psychiatry and Biobehavioral Sciences, Semel Institute,
UCLA, Los Angeles, USA
3Harbor UCLA Medical Center, Pediatrics, Los Angeles, USA
4UCLA Brain Injury Research Center, Dept of Neurosurgery and
Division of Pediatric Neurology, Los Angeles, USA
Brain imaging methods such as DTI (diffusion tensor imaging) are
especially sensitive to white matter (WM) damage in TBI. However,
analyses using tractography are complicated by damage and de-
creased FA (fractional anisotropy) characteristic of TBI, leading to
premature tract endings. We examined pediatric moderate/severe
TBI patients longitudinally in both the post-acute (2–4 months post-
injury) and chronic phase (12 months post-injury). We used a newly-
developed multi-atlas fiber tract clustering method to identify
differences in callosal WM integrity. We assessed FA, RD (radial
diffusivity), MD (mean), and AD (axial) along the corpus callosum
(CC), in 6 segments. We had 67 post-acute participants: 31 TBI
(mean age = 13.8 years, 7 F) and 36 control (mean age = 15.2 years,
16 F). Post-acutely, we found lower FA in TBI participants in the
CC_frontal segment across a wide area of projections from the CC
body and genu. We had 39 chronic participants: 19 TBI (mean
age = 16.1 years, 5 F), and 20 control (mean age = 16.0 years, 7 F). In
the CC_frontal, we found lower FA and higher RD and MD in TBI,
particularly in the genu and bilateral projections of the CC body. In
the CC_precentral, CC_postcentral, and CC_parietal segments, we
found higher RD and MD in the CC body and bilateral projections.
In the CC_temporal and CC_occipital, we found higher RD and MD
in the splenium and lateral projections. These indicate that WM
integrity differences between groups widen in the first year follow-
ing TBI, due to both further decreases in integrity in some areas and
smaller increases in integrity in the TBI group. This suggests con-
tinuing, progressive WM damage in the first year post-injury.
Key words
diffusion tensor imaging, fiber clustering, longitudinal, moderate/se-
vere TBI, tractography
B4-29
ADOLESCENT REPEAT TRAUMATIC BRAIN INJURY
CAUSES ACUTE CELL DEATH AND LONG-TERM IN-
FLAMMATION IN THE ANTERIOR PITUITARY OF RATS
Greco, T., Hovda, D.A., Prins, M.L.
UCLA, Los Angeles, USA
Hypopituitarism is an increasingly common occurrence observed in
adults and children after TBI. Despite the fact hormones play critical
role in brain and physical development little attention has been paid to
this area in adolescents. Previous studies have shown that a rat model
of mild repeat concussion (RTBI) decreases growth hormone, insulin-
like growth factor 1 and testosterone. Currently it is not yet under-
stood whether the observed hormonal deficiencies are due to injury
from the hypothalamus and/or the pituitary gland. Further, mecha-
nisms responsible for chronic hormone dysfunction have not been
delineated. It is hypothesized that due to location and anatomy of the
pituitary gland RTBI will result in acute cell death and chronic acti-
vation of inflammatory processes. Male postnatal day 35 rats were
given ether sham, 1 or 4 RTBI at 24 hr intervals. Western blots for a-II
spectrin, GFAP and IL-1b were performed at 24 hrs, 72 hrs, 1 week
and 1 month post-injury in both the hypothalamus and anterior pitu-
itary (AP). No significant differences in protein levels were detected
in the hypothalamus. In contrast, in the AP, there was a significant
86% decrease in a -II spectrin in RTBI animals at 24 hrs post-injury
and significant 1062% and 400% increases in GFAP and IL-1b, re-
spectively, 1 month post-injury. These results demonstrate that hy-
popituitarism following RTBI is due to mechanical injury to the AP
and not the hypothalamus. In addition, combined with evidence
of acute vascular damage in the AP following RTBI, this data sug-
gest cell death within the AP is responsible for acute hormonal
dysfunction while persistent inflammation may be responsible for
chronic hormonal deficits. Further work is needed to determine both
the mechanism of cell death within the AP and generation of chronic
inflammation.
Marilyn & Austin Anderson, UCLA BIRC, NFL Charities
Key words
concussion, endocrine, hypothalamus, inflammation, pituitary, repeat
traumatic brain injury
B4-30
HYPOTENSION PATTERNS AND VASOPRESSOR CHOICE
AFTER SEVERE TRAUMATIC BRAIN INJURY ACROSS
FIVE PEDIATRIC TRAUMA CENTERS
Kannan, N.1, Wang, J.1, Mink, R.B.2, Wainwright, M.S.3, Groner, J.I.4,
Bell, M.J.5 , Giza, C.C.6, Zatzick, D.F.1, Ellenbogen, R.G.1, Boyle,
L.N.1, Mitchell, P.H.1, Rivara, F.P.1, Vavilala, M.S.1
1University of Washington, Seattle, USA
2Harbor-UCLA, Harbor, USA
3Lurie Children’s Hospital of Chicago, Chicago, USA
4Ohio State University College of Medicine, Columbus, USA
5University of Pittsburgh, Pittsburgh, USA
6Mattel Children’s Hospital, UCLA, Los Angeles, USA
We examined systemic hypotension (systolic blood pres-
sure < 70 + 2*[age]) patterns and vasopressor use in 236 children £17
years with severe traumatic brain injury (TBI) during the first 72 hours
after admission at different treatment locations [Pre-hospital (PH),
Emergency Department (ED), Operating Room (OR) and Intensive
A-69