Download Current Trends in the Imaging of Diffuse Axonal Injury

September 2009
Current Trends in the
Imaging of Diffuse
Axonal Injury
Edwin Chu, MS IV
University of Texas Medical School in San Antonio
Gillian Lieberman, MD
Harvard Medical School
Beth Israel Deaconess Medical Center
Edwin Chu, MS IV
Gillian Lieberman, MD
Outline
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Introduction to Traumatic Brain Injury
Our Patient: MC
Diffuse Axonal Injury (DAI)
Imaging Modalities for Diffuse Axonal Injury
Summary
Acknowledgements
References
Edwin Chu, MS IV
Gillian Lieberman, MD
Introduction to Traumatic Brain
Injury (TBI)
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Defined as damage to the brain from an external
mechanical force.
Examples of such forces include rapid
acceleration or deceleration motions, impact
injuries, or penetration by a projectile
Incidence: 200-225/100,000
12% of all U.S. hospital admissions are TBIrelated
Meythaler, J. M. (2001). "Current concepts: diffuse axonal injury-associated traumatic brain injury."
Archives of physical medicine and rehabilitation 82(10): 1461-71.
Edwin Chu, MS IV
Gillian Lieberman, MD
Our Patient: MC
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CC: Traumatic Brain Injury
HPI: 23 y/o M with unknown medical history
transferred from an outside hospital s/p high speed
(~100mph) motorcycle vs. bus accident. Pt was
helmeted. In the field, GCS 3. Negative tox screen.
GCS- Glasgow Coma Score
Edwin Chu, MS IV
Gillian Lieberman, MD
On Admission- Patient MC: CT Imaging
Axial non contrast CT imaging showing
hyperdensity (green box) in left frontal lobe
consistent with a hemorrhagic contusion. No
other signs of hemorrhage were seen acutely.
Edwin Chu, MS IV
Images from PACS, BIDMC
Gillian Lieberman, MD
3 Days Later- Patient MC : MRI T2 Flair
Areas of
Hemorrhage
Axial T2 weighted Flair MR imaging
showing hyperintense signal in the right
and left grey-white matter interface and
splenium of the corpus callosum
Axial T2 weighted Flair MR Imaging
showing hyperintense signal in the right
posterior limb of the internal capsule
and a left frontal lobe contusion
Edwin Chu, MS IV
Images from PACS, BIDMC
Gillian Lieberman, MD
3 Days Later- Patient MC : MRI T2 Flair
Axial T2 weighted Flair MR imaging
showing hyperintense signal in the
corpus callosum
Edwin Chu, MS IV
Images from PACS, BIDMC
Gillian Lieberman, MD
3 Days Later- Patient MC : MR
Susceptibility Weighted Imaging
Areas of
Hemorrhage
Axial SW MR imaging showing
hypo-intense signal in the right and
left grey-white matter interface and a
left frontal lobe contusion
Axial SW MR imaging showing hypointense lesions in the right grey-white
matter interface and splenium; left
frontal lobe contusion
Edwin Chu, MS IV
Images from PACS, BIDMC
Gillian Lieberman, MD
3 Days Later- Patient MC : MR
Susceptibility Weighted Imaging
Axial T2 weighted SW MR imaging
showing hypo-intense signal in the
corpus callosum
Axial T2 weighted SW MR imaging
showing hypo-intense signal in the
corpus callosum
Edwin Chu, MS IV
Images from PACS, BIDMC
Gillian Lieberman, MD
Diffuse Axonal Injury
Biomechanics, Pathogenesis, Stages of
Damage, and Long-term Consequences
Diffuse Axonal Injury (DAI)
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Severe head trauma can produce diffuse axonal
injury characterized by punctate hemorrhagic or
non-hemorrhagic lesions primarily in white matter
tracts
Common sites: Parasagittal white matter, grey-white
matter junctions of the cerebral cortex, corpus
callosum, and brainstem
Occurs in 40-50% of patients hospitalized for TBI
Affects more than 2 million people every year
Meythaler, J. M. (2001). "Current concepts: diffuse axonal injury-associated traumatic brain injury."
Archives of physical medicine and rehabilitation 82(10): 1461-71.
Edwin Chu, MS IV
Gillian Lieberman, MD
DAI and its Long-Term
Consequences
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26,000 deaths/yr are due to DAI
20,000- 45,000 surviving patients/yr suffer
neurobehavioral or physical impairments
Average hospital cost per patient: $117,000
Direct health care costs: $25 billion/year
Meythaler, J. M. (2001). "Current concepts: diffuse axonal injury-associated traumatic brain injury."
Archives of physical medicine and rehabilitation 82(10): 1461-71.
Edwin Chu, MS IV
Gillian Lieberman, MD
Biomechanics of DAI
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Commonly referred to as a shear force injury
Rapid head motions produce inertial forces
which cause rotational acceleration of the brain
leading to shearing and strain of axons
Rapid stretch of an axon leads to damage to the
neuron’s cytoskeleton. Axonal transport
continues until local inflammation causes further
cytoskeleton breakdown
Edwin Chu, MS IV
Gillian Lieberman, MD
Pathogenesis of Microscopic Axonal
Changes
Brain Injury
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Influx of Na+ and Ca2+ through
respective channels
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Axonal Swelling
Axonal cytoskeleton damage
Accumulation of axonal transport
proteins within swellings
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Increased cytoskeleton
damage + protein
accumulation = axon
disconnection
Axon disconnection
leads to irreversible
damage
Pathologic Feature: Bulb
formation
Edwin Chu, MS IV
Gillian Lieberman, MD
Histopathology of DAI
Below: Silver stain of the same area
indicating the axonal terminal bulbs.
Top: Low power view of hematoxylineosin stain demonstrating DAI and
petechial hemorrhages
Images from: Meythaler, J. M. (2001). "Current concepts: diffuse axonal injury-associated traumatic
brain injury." Archives of physical medicine and rehabilitation 82(10): 1461-71.
Edwin Chu, MS IV
Gillian Lieberman, MD
Stages of DAI
Stage Areas Affected
parasagittal regions of the frontal lobes
- periventricular temporal lobes
- internal and external capsules
- cerebellum
I
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II
Stage I areas + corpus callosum
III
Stage I + Stage II areas + dorsolateral quadrants of the rostral
brain stem
Adams, J. H. (1989). "Diffuse axonal injury in head injury: definition, diagnosis and grading."
Histopathology 15(1): 49-59.
Edwin Chu, MS IV
Gillian Lieberman, MD
Imaging Modalities for Diffuse
Axonal Injury
Edwin Chu, MS IV
Gillian Lieberman, MD
Imaging of DAI: CT
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CT imaging is first line for any neurotrauma
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Benefits
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Widely available in most
hospitals in the US
Comparatively
inexpensive
Good, quick test for
injuries that require
immediate surgical
attention
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Drawbacks
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Initially 50-80% of pts
with DAI will have
normal CT scans
Less sensitivity for
detecting DAI
Edwin Chu, MS IV
Toyama, Y. (2005). "CT for acute stage of closed head injury." Radiation medicine 23(5): 309-16.
Gillian Lieberman, MD
Examples of DAI on CT Imaging:
Companion Patient TC
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HPI: 22 y/o F being found down in the road,
entangled with her bicycle, unresponsive,
unhelmeted, pupils unequal. Initial CGS was 4
upon arrival to ED.
Edwin Chu, MS IV
Gillian Lieberman, MD
Companion Patient TC:
Axial Non-Contrast CT Imaging
Areas of Hemorrhage
Soft Tissue Edema
Edwin Chu, MS IV
Images from PACS, BIDMC
Gillian Lieberman, MD
Companion Patient TC:
Axial Non-Contrast CT Imaging
Areas of Hemorrhage
Soft Tissue Edema
Edwin Chu, MS IV
Images from PACS, BIDMC
Gillian Lieberman, MD
Companion Patient TC:
Axial Non-Contrast CT Imaging
Areas of Hemorrhage
Edwin Chu, MS IV
Images from PACS, BIDMC
Gillian Lieberman, MD
More Examples: Non-Contrast CT
Imaging showing Hemorrhagic DAI
Lesions
Black arrows:
areas of hemorrhagic
foci
Left Image from: Provenzale, J. (2007). "CT and MR imaging of acute cranial trauma."
Emergency radiology 14(1): 1-12.
Right Image from: Toyama, Y. (2005). "CT for acute stage of closed head injury." Radiation
medicine 23(5): 309-16.
Edwin Chu, MS IV
Gillian Lieberman, MD
Imaging of DAI: MRI
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MRI has greater sensitivity in detecting DAI
Commonly used techniques include Flair, DWI, and
GRE, and SWI*
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Kinoshita et al.- DWI sensitivity in detecting DAI is
comparable to Flair
Tong et al.- Number of hemorrhagic DAI lesions seen on
SWI was 6 times greater than that on conventional T2*
weighted 2D GRE imaging and the volume of hemorrhage
was approx 2 fold greater
* Flair- Fluid Attenuated Inversion Recovery
DWI- Diffusion weighted Imaging
GRE- Gradient Recalled Echo
SWI- Susceptibility Weighted Imaging
Edwin Chu, MS IV
Gillian Lieberman, MD
T2 MR Imaging of DAI
Sagittal T2-weighted MR image showing hyper-intense
signal within the corpus callosum (white arrows)
Image from: Provenzale, J. (2007). "CT and MR imaging of acute cranial trauma." Emergency
radiology 14(1): 1-12.
Edwin Chu, MS IV
Gillian Lieberman, MD
MR Flair: Conspicuity of DAI
Lesions
MR FLAIR image showing
hyper-intense lesion in the left
splenium
MR FLAIR image showing
hyper-intense lesion in the left
frontal grey-white matter
interface
Images from: Kinoshita, T. (2005). "Conspicuity of diffuse axonal injury lesions on diffusionweighted MR imaging." European journal of radiology 56(1): 5-11.
Edwin Chu, MS IV
Gillian Lieberman, MD
MR DWI: Conspicuity of DAI
Lesions
MR DWI–Gx image showing
high-intensity lesion in the
splenium
MR DWI–Gz image showing highintensity lesion in the left frontal
grey-white matter interface
Images from: Kinoshita, T. (2005). "Conspicuity of diffuse axonal injury lesions on diffusionweighted MR imaging." European journal of radiology 56(1): 5-11.
Edwin Chu, MS IV
Gillian Lieberman, MD
More Lesions are seen on
Susceptibility Imaging: Comparing
T2 and SWI
A) Axial T2 MRI
B) Axial Susceptibility-weighted MRI
Small hemorrhagic shearing injuries in
the left frontal subcortical white matter
(Black arrows)
Image from: Tong, K. A., S. Ashwal, et al. (2008). "Susceptibility-weighted MR imaging: a review of clinical
applications in children." AJNR. American journal of neuroradiology 29(1): 9-17.
Edwin Chu, MS IV
Gillian Lieberman, MD
More Lesions are seen on
Susceptibility Imaging: Comparing
T2 and SWI
C) Axial T2 MRI
D) Axial Susceptibility-weighted
MRI
Hemorrhagic shearing foci
(open arrows) in the left frontal
white matter, right subinsular
region, and left splenium
Image from: Tong, K. A., S. Ashwal, et al. (2008). "Susceptibility-weighted MR imaging: a review of clinical
applications in children." AJNR. American journal of neuroradiology 29(1): 9-17.
Edwin Chu, MS IV
Gillian Lieberman, MD
The Emergence of MRI Diffusion
Tensor Tractography (DTT)
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DTT is rapidly becoming another modality to
look for DAI in the acute phase
Modality can characterize white matter integrity
by measuring fractional anisotropy (FA)
Fractional anisotropy is the degree of alignment
of the underlying nerve fibers (ratio: 0 to 1)
Wang, J. Y., B. Khamid, et al. (2008). "Diffusion tensor tractography of traumatic diffuse axonal injury."
Archives of neurology 65(5): 619-26.
Edwin Chu, MS IV
Gillian Lieberman, MD
Using DTT for Long-Term DAI
Follow-up
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Skoglund et al.
22 y/o F with closed head injury. Comparison
images of Axial T2 and DTT at 6 days post-injury
and 18 months post-injury
 Results: In follow-up imaging, conventional MRI
showed no pathology. However, in DTT imaging,
FA values had improved but did not normalize.
 Conclusion: MR-DTT may be more sensitive to
DAI than conventional MR imaging.
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Skoglund, T. S. (2008). "Long-term follow-up of a patient with traumatic brain injury using
diffusion tensor imaging." Acta radiologica (Stockholm, Sweden : 1987) 49(1): 98-100.
Edwin Chu, MS IV
Gillian Lieberman, MD
Results: Long-Term DAI Follow-up
with DTT
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a) 6 days post injury- Axial
T2 MR image showing
hyper-intense lesion in left
pons
b) 18 months post injuryAxial T2 MR image showing
no lesion
c) 6 days post injury- Axial
DTT image showing
decreased blue intensity
d) 18 months post injuryAxial DTT image showing
moderately improved blue
intensity
Images from: Skoglund, T. S. (2008). "Long-term follow-up of a patient with traumatic brain injury
using diffusion tensor imaging." Acta radiologica (Stockholm, Sweden : 1987) 49(1): 98-100.
Edwin Chu, MS IV
Gillian Lieberman, MD
Fractional Anisotropy in Long-Term
DAI Follow-up
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FA values on left side
improve 18 months postinjury but do not
normalize to right-sided
values
Key:
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dx – Patient’s right side
sin – Patient’s left side
Graph from: Skoglund, T. S. (2008). "Long-term follow-up of a patient with traumatic brain injury
using diffusion tensor imaging." Acta radiologica (Stockholm, Sweden : 1987) 49(1): 98-100.
Edwin Chu, MS IV
Gillian Lieberman, MD
Summary
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Diffuse Axonal Injury is caused by traumatic brain
injury and can be characterized by punctate
hemorrhagic or non-hemorrhagic lesions primarily
in white matter tracts
MRI is now the imaging of choice for detecting
DAI. SWI and DWI are the best techniques
DTT holds promising results as an imaging
modality for the acute and long-term follow-up of
DAI patients
Edwin Chu, MS IV
Gillian Lieberman, MD
Acknowledgements
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Special thanks to Dr. Rafeeque Bhadelia for help
with this index case and presentation
Dr. Rivka Colen
Dr. Gillian Lierberman
Edwin Chu, MS IV
Gillian Lieberman, MD
References
Adams, J. H. (1989). "Diffuse axonal injury in head injury: definition, diagnosis and grading."
Histopathology 15(1): 49-59.
Kinoshita, T. (2005). "Conspicuity of diffuse axonal injury lesions on diffusion-weighted MR
imaging." European journal of radiology 56(1): 5-11.
Meythaler, J. M. (2001). "Current concepts: diffuse axonal injury-associated traumatic brain injury."
Archives of physical medicine and rehabilitation 82(10): 1461-71.
Provenzale, J. (2007). "CT and MR imaging of acute cranial trauma." Emergency radiology 14(1): 1-12.
Skoglund, T. S. (2008). "Long-term follow-up of a patient with traumatic brain injury using diffusion
tensor imaging." Acta radiologica (Stockholm, Sweden : 1987) 49(1): 98-100.
Smith, D. H. (2003). "Diffuse axonal injury in head trauma." The Journal of head trauma
rehabilitation 18(4): 307-16.
Tong, K. A., S. Ashwal, et al. (2008). "Susceptibility-weighted MR imaging: a review of clinical
applications in children." AJNR. American journal of neuroradiology 29(1): 9-17.
Toyama, Y. (2005). "CT for acute stage of closed head injury." Radiation medicine 23(5): 309-16.
Wang, J. Y., B. Khamid, et al. (2008). "Diffusion tensor tractography of traumatic diffuse axonal
injury." Archives of neurology 65(5): 619-26.
Edwin Chu, MS IV
Gillian Lieberman, MD