david baxter - biosap
DESCRIPTION
Blast Injury Outcome Study in Armed Forces PersonnelTRANSCRIPT
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BIOSAP: Blast Injury Outcome Study in
Armed forces Personnel
Major David Baxter RAMC
SSNP Conference
September 2012
Aim of this presentation
The team:
Major David Baxter
Dr David Sharp (IC)
Dr Tony Goldstone (IC)
Dr Richard Greenwood (UCL)
Mr Neil Kitchen (UCL)
Location:
Computional, Clinical & Cognitive Neuroimaging Lab (C3NL) –
The Hammersmith Hospital (IC)
The Robert Steiner MRI Center – The Hammersmith Hospital (IC)
Defence Medical Rehabilitation Centre - Headley Court
Blast wave physics Blast wave physics
Primary, secondary, tertiary and quaternary injury
Cernak et al Traumatic brain injury: an overview of pathobiology with emphasis on military populations. Journal of
Cerebral Blood Flow & Metabolism (2010) 30, 255–266
Background
Background:
Civilian TBI – outcome is poorly understood. Because pathophysiology is
not well understood.
This is true (more so) for blast. Nevertheless…
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Improvements in diagnosis of non-penetrating brain
injury
Conventional
imaging
i.e. xray and CT
MRI; T1, T2, Flair DTI, SWI, Gradient Echo
Focal injury and white matter damage
Contusion location Diffuse axonal injury
Grade 2: lesions in corpus callosum
Grade 3: lesions also in brainstem
Adams et al ‘85
Hypothesis and Impact
Aim:
1. To characterize the neuropsychological and endocrine
consequences of blast traumatic brain injury.
2. To compare this to civilian traumatic brain injury.
Hypothesis:
1. Blast causes a specific pattern of white matter damage,
that can be assessed using MRI.
Impact:
1. Gives the capability of screening blast injured soldiers
2. Provide evidence about the mechanism of blast injury.
What is the BIOSAP project and what are its aims
Blast TBI
Imaging studies Endocrine assessment Psychological assessment
Imaging studies Endocrine assessment Psychological assessment
ADMEM database
DMRC Headley Court
B’ham hospitals
Clinician referral
Criteria
Inclusion • Moderate to severe traumatic brain injury
• GCS <14
• LOC >30mins
• PTA >24hrs
• History of Blast injury.
• Persistent cognitive impairment.
• No significant premorbid neurological or
psychiatric illness.
• Able to give informed consent.
• Ability to perform the scanning paradigm.
• Clinically stable.
Exclusion • Cognitive impairment such that the subject will
be unable to cooperate.
• Significant language or visuo-spatial
impairments..
• Penetrating head injury or neurosurgery.
• Overt bleeding visible on CT (excluding the
presence of microbleeds – a marker of diffuse
axonal injury).
MRI assessment
Structural MRI
T1
T2 Flair
T2 FFE – Gradient Echo
Diffusion tensor imaging - DTI
Susceptibility Weighted Imaging – SWI
Functional MRI
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Neuropsychological & Psychiatric Test Battery
Cognitive: (developed with Professor Jane Powell - Goldsmiths)
Intellectual function - WASI similarities, WASI Matrix reasoning
Executive function - Trail Making Test, Inhibition/switching, Letter fluency
Memory function and learning - People Test immediate recall
Information processing speed - Colour naming (s), Word reading (s)
Psychiatric:
Including: AGHDA, Beck Depression Inventory, Epworth Sleepiness, Nottingham
Health Profile, SF-36
PTSD
Mood disturbance
Anxiety
Endocrine Assessment
• Traumatic brain injury produces significant dysfunction in the
hypothalamic-pituitary axis in a significant number of patients
[Schneider et al., 2007]
• Impairments persisting in 15-50% of patients. E.g. severe growth
hormone deficiency is seen in 10-20% of patients following traumatic
brain injury.
• Limits brain recovery.
• Important therapeutic opportunity.
Case 1: History
28yo male
Top cover
Wearing Helmet and eye protection
50 Kg IED.
Multiple fractures. Superficial lacerations. Left sided pneumothorax.
Initial GCS 12/15
2 weeks of retrograde amnesia
6 weeks of post-traumatic amnesia
On neuropsychological assessment;
Impaired executive function, memory and processing speed
Case 1: Structural imaging findings
T2Flair Gradient Echo
Case 1: Outcome
Returned to work in a limited capacity but struggling…
Case 2: History
27yo. Male
Passenger in vehicle
Wearing body armour and Helmet
IED of unknown size
Multiple fractures and lacerations. Left sided pneumothorax.
Initial GCS 13/15
1 day retrograde amnesia
4 days post traumatic amnesia
On neuropsychological assessment;
Impaired memory
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Case 2: Structural imaging findings
T2Flair Gradient Echo
Case 2: Outcome
Currently studying for Msc.
Case summary
Conventional imaging
1. Gradient echo imaging is more sensitive than standard T1 and Flair to
the changes associated with diffuse axonal injury
2. But…the presence of microbleeds can still be associated with very
variable clinical outcome.
Results
• 20 blast injured soldiers
• 40 age matched civilians with moderate
to severe TBI
• 40 uninjured civilian controls
Study participant demograhics
Controls Military Civilian Difference
Age 30.6 yrs (SD
6.7)
29.4 yrs (SD
5.8)
30.3 yrs (SD
7.6)
No
difference
Time since
injury
n/a 14.6 mnths
(SD 5.9)
12 mnths
(SD 12.7)
No
difference
Contusion n/a 9 (45%) 10 (50%) No
difference
Microbleeds n/a 5 (25%) 5 (25%) No
difference
Diffusion tensor imaging
Mori et al Neur
Cortex
White matter - TBI
Low fractional anisotropy
& High mean diffusivity
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DTI Results TBSS Pattern analysis
Pattern analysis results Now focus on the bTBI group
Endocrine assessment results Region of Interest analysis
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Neuropsychological and QoL assessment results Summary
1. MRI changes following blast traumatic brain injury are associated with,
neuropsychological, neuropsychiatric and endocrine changes.
2. Blast traumatic brain injury produces a hetreogenous white matter
injury pattern, however some regions appear to particularly vulnerable
to injury from blast.
3. We will attempt to use this research to identify patients who will go on
to have a poor clinical outcome, and provide information about the
mechanism of blast.
BIOSAP
Thanks to;
DPMD Prof M Midwinter
Dr A K Samra
Mjr C Lethbridge
DMRC Col Etherington
Wng Cmdr A Bennett
Kit Malia
Doreen Rowland
Ronel Terblanche
Alison Lutte-Elliott
Goldsmiths Prof Jane Powell