Els Fieremans Nand Miskin Ajax George James Golomb Center for biomedical imaging New York University School of Medicine New York NY Control 1144 Poster eP104 Diffusion Kurtosis of the Cortical Spinal Tract Characterizes ID: 803177
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Slide1
Benjamin
Ades-Aron, Stephanie Yeager, Els Fieremans, Nand Miskin, Ajax George, James GolombCenter for biomedical imaging, New York University School of Medicine, New York, NY
Control #: 1144
Poster #: eP-104
Diffusion Kurtosis of the Cortical Spinal Tract Characterizes
Adult Normal Pressure
Hydrocepalus
Slide2Speaker Name: Benjamin
Ades
-Aron
I have no financial interests or relationships to disclose with regard to the subject matter of this presentation.
Declaration of
Financial Interests or Relationships
Slide3Purpose
To investigate changes in cortical-spinal tract (CST) integrity in patients with Normal Pressure Hydrocephalus (NPH) using tractogaphy and diffusion MRILocalize exactly where NPH effects the CSTTo determine whether this method can be used as a diagnostic tool to differentiate patients with NPH from control groupsTo study whether permanent cell damage can be assessed in NPH using diffusion model biomarkers
#1144
benjamin.adesaron@gmail.com
Slide4Diffusion Kurtosis ImagingDKI is sensitive to myelination, axonal integrity, and
intravoxel fiber orientationAxial Diffusivity (AD) axonal integrity Axial kurtosis (AK) fiber coherence / presence of microstructureAxonal Water Fraction (AWF) demyelination and axonal atrophy
Demyelination/axonal loss
Detected by AD and AWF
Fiber alignment Detected by AK
Images from:Fieremans E, Novikov DS et al., ISMRM 2012 #465 and Atsushi Nakanishi et al. Neuroradiology 2013
#1144
benjamin.adesaron@gmail.com
Slide5Seed ROIs in the cerebral peduncle and precentral gyrusDiffusion and Kurtosis parameters were resampled onto streamlines as scalars
Streamlines were truncated and normalized for group comparisons
FA image
seed ROIs
Streamlines
Weighted tracts
Tractography
Mrtrix
package (J-D
Tournier
, Brain Research Institute, Melbourne, Australia)
AK image
AD
image
AWF
image
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benjamin.adesaron@gmail.com
Slide6Materials and Methods
Number of subjects
Age
Gender m/f
NPH
14
58 – 87, mean 75
7/7
Alzheimer's
10
60 – 85, mean 75
5/5
Control
11
60 – 87, mean 75
6/5
Data
Acquisition
3T
MRI acquired with b = 0, 1000, and 2000 s/mm2 in 60
directions
Diffusion Processing
Standard
Diffusion and Kurtosis measures (mean, axial, and radial) were computed after smoothing and motion + eddy correction in FSL
WMTI metrics were computed in addition to standard model parameters
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benjamin.adesaron@gmail.com
Slide7Alzheimer’s
healthy controlNPH
Demonstration of Group Differences
Alzheimer’s
Healthy control
NPHAxial DiffusionAxial Kurtosis
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benjamin.adesaron@gmail.com
Slide8Along-Tract Axial Diffusivity
*
*
Significant differences between NPH and control groups occur between
60% and 85%
0
10
20
30
40
50
60
70
80
90
100
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benjamin.adesaron@gmail.com
Slide9Along-Tract Axial Kurtosis
*
*
Significant between 50% and 90%
*
*
0
10
20
30
40
50
60
70
80
90
100
#1144
benjamin.adesaron@gmail.com
Slide10Along-Tract Axonal Water Fraction
*
*
Significant between
70% and 85%
*
*
*
*
0
10
20
30
40
50
60
70
80
90
100
#1144
benjamin.adesaron@gmail.com
Slide11ROC analysis AUC values
NPH vs Alzheimer’sNPH vs Healthy Controls Alzheimer’s vs Healthy ControlsFA
0.64
0.52
0.76
MD0.910.980.79RD0.880.98
0.84
AD
0.92
1.0
0.51
MK
0.61
0.83
0.82
RK
0.68
0.58
0.82
AK
0.92
0.99
0.67
AWF
0.65
0.93
0.86
AUC is a measure of diagnostic accuracy
75% of the distance along the tract (corona radiata)#1144 benjamin.adesaron@gmail.com
Slide12ResultsAxial Diffusivity was found to be greater in NPH than Alzheimer’s and control groups in the periventricular CSTAxial Kurtosis and Axonal Water Fraction were lower than control groupsMain statistical differences were found in the superior corona
radiata and posterior internal capsuleAD and AK have high diagnostic accuracy
#1144 benjamin.adesaron@gmail.com
Slide13Blue
:
P
(controls
)
Red: P(NPH)
Tracts do not pass through areas
of maximum white matter disease
Leukoareosis
Probability Maps
Probability of
luko
Residuals
Region where only NPH is affected
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benjamin.adesaron@gmail.com
Slide14Regression
for AD and controls
only
No correlation between volume of
lukoarosis
and axial Kurtosis in NPH at high axial kurtosis values
While
diffusion metrics
correlate
with the presence of white matter legions
, these
legions
do not
explain the
the
differences in diffusion between groups
Are we detecting
leukoareosis
rather than NPH?
#1144
benjamin.adesaron@gmail.com
Slide15Conclusions
Pathology in NPH is located in the upper periventricular part of the CST. The superior corona radiata and some posterior internal capsule
Differences in Axial Kurtosis imply that the CST in NPH is more tightly aligned than that of AD and controls
Increased axial diffusivity and axonal water fraction imply neuronal loss in the CST in NPH patients compared to AD and controls
Axonal loss reflected by increased AD and decreased AWF may reflect irreversible
damage done to the CST due to mechanical stress placed on white matter tissue by the expanding ventriclesLeukoareosis cannot account for the changes we have seen#1144 benjamin.adesaron@gmail.com
Slide16Thank you
Ajax George, M.D.James Golomb, M.D.#1144 benjamin.adesaron@gmail.com
Slide17ReferencesHattori, T., et al. "Altered microstructure in corticospinal tract in idiopathic normal pressure hydrocephalus: comparison with Alzheimer disease and Parkinson disease with dementia." American Journal of Neuroradiology 32.9 (2011): 1681-1687. Hong, Y. J., et al. "Differences in microstructural alterations of the hippocampus in Alzheimer disease and idiopathic normal pressure hydrocephalus: a diffusion tensor imaging study." American Journal of Neuroradiology 31.10 (2010): 1867-1872.
Fieremans, E., et al. "Novel white matter tract integrity metrics sensitive to Alzheimer disease progression." American Journal of Neuroradiology 34.11 (2013): 2105-2112 #1144 benjamin.adesaron@gmail.com