NA-MIC National Alliance for Medical Image Computing (Pre-)Clinical and Applications with DTI Guido...

NA-MICNational Alliance for Medical Image Computing http://na-mic.org

(Pre-)Clinical and Applications with DTI

Guido Gerig

UNC Chapel Hill

ASNR 2003 –Washington,DC DT-MRI Alexander 2

DTI Applications• Normal brain development and aging

• Congenital anomalies and diseases of white matter

• Traumatic brain injury

• Encephalopathies – toxic, metabolic, infectious

• Demyelinating and neurodegenerative diseases

• Ischemia and stroke

• Neoplasm, preoperative planning

• Epilepsy

• Dementia, schizophrenia, depression

• Developmental disorders - fragile X, autism

• Spinal Cord


Courtesy J. Neil Washington Univ., St. Louis

Normal Brain Development


WM AnisotropyChanges with Age

genu

frontalpericallosal

centrumsemiovale

GenuLeft pericallosalRight pericallosal

.3

.4

.5

.6

.7

.8

20 30 40 50 60 70 80Age

Anterior

FA

SpleniumLeft pericallosalRight pericallosal

.3

.4

.5

.6

.7

.8

20 30 40 50 60 70 80

Age

Posterior

FA

.34

.36

.38

.40

.42

.44

.46

.48

20 30 40 50 60 70 80

Age

Centrum Semiovale

parietalpericallosal

splenium

Pfefferbaum et al.MRM 2000

Courtesy K. Lim, Univ. Minn.


R. Bammer, F. Fazekas, Neuroim Clinics N Am, Feb. 2002. S T A N F O R D S C H O O L OF M E D I C I N E

Lucas MRS/I Center

S T A N F O R D S C H O O L OF M E D I C I N E

Lucas MRS/I Center

Multiple Sclerosis


DTI in Cerebral Neoplasms

Deviated

Edematous Destroyed

Infiltrated


Tract Displacement T2W ADC

FA FA 1

Cerebral Palsy

Courtesy of Susumu Mori

NA-MICNational Alliance for Medical Image Computing http://na-mic.org

PNL Schizophrenia Study

Martha Shenton, PNL Harvard

Guido Gerig, UNC Chapel Hill

National Alliance for Medical Image Computing http://na-mic.org Slide 14

Atlas: Average + Set of transformed tensor fields

ROIs and tracts in atlas space transferred to every image.


Tractography in PNL Atlas

Corpus Callosum middle part

Cingulum full

Cingulum “spine”


Tractography per Group

Cingulum SZ GroupCingulum Control Group

Tractography applied to tensor fields of the set of controls mapped to the atlas (left) ad the set of SZ mapped to the atlas (right).


Very, very preliminary tests …

FA along cingulum per group

0

0.1

0.2

0.3

0.4

0.5

0.6

-80 -60 -40 -20 0 20 40

arclength (mm)

FA

FA-NC

FA-SZ

Poly. (FA-SZ)

Poly. (FA-NC)

SZ seems to have lower FA in middle portion of cingulum.

What does it mean w.r.t. diffusion properties?


ctd.

SZ group seems to have lower lambda1 and slightly higher radial diffusion (average lambda2 + lambda3) in middle region.

L1 along cingulum per group

0

2

4

6

8

10

12

14

-80 -60 -40 -20 0 20 40

arclength (mm)

L1

L1-NC

L1-SZ

Poly. (L1-SZ)

Poly. (L1-NC)

L23 along cingulum per group

0

1

2

3

4

5

6

7

8

9

10

-80 -60 -40 -20 0 20 40

arclength (mm)

L23

L23-NC

L23-SZ

Poly. (L23-SZ)

Poly. (L23-NC)


ctd.

MD along cingulum per group

0

2

4

6

8

10

12

-80 -60 -40 -20 0 20 40

arclength (mm)

MD

MD-NC

MD-SZ

Poly. (MD-SZ)

Poly. (MD-NC)

GA along cingulum per group

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

-80 -60 -40 -20 0 20 40

arclength (mm)

GA

GA-NC

GA-SZ

Poly. (GA-SZ)

Poly. (GA-NC)

MD seems very similar for both groups.

GA shows same pattern as FA but much higher values.


DTI Population Atlases

Related work:• Alexander, D., Pierpaoli, C., Basser, P., Gee, J.: Spatial transformations of diffusion

tensor magnetic resonance images. IEEE Transactions on Medical Imaging 20(11) (2001)

• Zhang, H., Yushkevich, P., Gee, J.: Registration of diffusion tensor images. In: CVPR. (2004)


DTI Population Atlases

Neonates (N=50)

1yr olds (N=25)

2yr olds (N=15)


Fiber Tractography in Atlases

Neonate atlas DTI 1yr atlas DTI

fornix and uncinate

genu, splenium, motor

uncinate

cingulate

motor tracts


Krabbe Disease

Maria Luisa Escolar, M.D.Director, Program for the Study of Neurodevelopmental Function in Rare DisordersCenter for the Study of Development and LearningUniversity of North Carolina at Chapel Hill


Neuroimaging for Phenotyping

Cortex

Motor

CerebellarDeep WM

PontineNucleus

Middle CerebellarPeduncle

Fibers throughInternal Capsule

SuperiorCerebellarPeduncle

Dentate

Thalamus

Motor Circuitry Motor Tract

Cerebellar Peduncles

UCBT


Neuroimaging for Phenotyping: Atlas-based white matter analysis

Patient DTI

Please note absence of wm structuring (high FA) in right external capsule

Normative Atlas (50 neonates), DTI: Average and statistics

Z-scores indicating regions with significant differences


Bundles obtained from 50case atlas by tractography

Full tracts Selection of center and off-center regions of interest


Early postnatal development of white matter: Joint analysis of sMRI and DTI

• Analysis of white matter in healthy controls (N=47)• Co-registration of sMRI and DTI (deformable)• Fibertract-based segmentation of ROIs• Quantitative analysis of FA, MD, T1w, T2w

FA MD T1w T2w

FA MD T1w T2w


Early postnatal development of white matter

Analysis of white matter in healthy controls (N=47)

Myelination and axon elimination:

• FA center >> peripheral• FA splenium > genu• MD splenium & genu >

intcaps • T1w splenium & genu <

intcaps

Gilmore/Lin/Gerig , submitted AJNR


Early postnatal development of white matter

Joint analysis of structural MRI and DTI:Genu at center (non myelinated) versus internal capsule (myelinated)– FA genu ≈ FA intcaps– T1w genu >> T1w intcaps

Analysis detects differences between dense structuring and early myelination

Procedure to be used to measure maturation process


Longitudinal Follow-up

Intracranial Volume

Neonate Year 10

250000

500000

750000

1000000

1250000

* p < 0.0001

Vo

lum

e m

m3

Neonate 1 year old

Total Ventricle Volume

Neonate 1 year0

2500

5000

7500

10000

* p < 0.0001

Vo

lum

e m

m3


Corpus Callosum Tracts: Study of Early Development

Neonate (2 wks) Adult

Corpus callosum: Commissural bundles, color coding of FA (0=blue, 1=red)

Infant (1 year)


“Maturation” of white matter tracts

Splenium

Neonate 1 year 0

2

4

6

8

10

12

14

16

18

p < 0.0001

AD

C

Left Internal Capsule (Brainstem)

Neonate 1 year0

2

4

6

8

10

12

14

16

18

p < 0.0001

AD

C

Splenium

Neonate I year 0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

p < 0.0001

FA

Left Internal Capsule (Brainstem)

Neonate 1 year0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

p < 0.4092

FA


Tensor Statistics Genu/Splenium: Neonate to 1years

Neo

1yr

Neonate

1year

genu splenium

MD MD

FA FA


Conclusions

• Diffusion Imaging adds a measurement not obtained by other structural imaging sequences.

• Invaluable for studying white matter disease, lesions, neurodevelopment and neurodegeneration.

• MR-DTI made huge progress to provide high resolution with isotropic voxels.

• Tools for comprehensive analysis available.

NA-MIC National Alliance for Medical Image Computing (Pre-)Clinical and Applications with DTI Guido...

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