Deep understanding of myocardial structure of the heart would unravel crucial knowledge for clinical and medical procedures. Although the muscular architecture of the heart has been debated by countless researchers, the controversy is still alive. Diffusion Tensor MRI, DT-MRI, is a unique imaging technique for computational validation of the muscular structure of the heart. By the complex arrangement of myocites, existing techniques can not provide comprehensive descriptions of the global muscular architecture. We introduce a multiresolution reconstruction technique based on DT-MRI streamlining for simplified global myocardial model generation. Our reconstructions can restore the most complex myocardial structures and indicate a global helical organization.

1. Multiscale Tractography for
Representing Heart Muscular
Architecture
Ferran Poveda, Debora Gil, Albert Andaluz, & Enric Marti´
Universitat
Autònoma
de Barcelona

2. Universitat
Autònoma
de Barcelona
Medical Motivation
2
Muscular
Architecture plays
a key role in
myocardial
functionality

3. Universitat
Autònoma
de Barcelona
Medical Background
NIELS STENSEN
1663
RICHARD LOWER
1669
JEAN B. SENAC
1911
F. TORRENT-GUASP
1957
3
•Dissection procedure
•Histologic validation
Subjectivity
Several Models BUT no agreement

4. Universitat
Autònoma
de Barcelona
DT-MRI & Tractography
e1
e2
e3
4
rohmer et al. 2006
•DT-MRI:
Objective Measure of
Spatial Arrangement of
myocytes
•Tractography:
Computational representation
of architecture

5. Universitat
Autònoma
de Barcelona
Helm et al. 2005Frindel et al. 2008
Existing Methods
5
rohmer et al.
2006
Zhukov et al.
2003
Limitations of
tractographic
reconstructions:
• Data incompleteness
• Partial
Reconstruction
• Orientation of DT-MRI
• Detail hinders abstraction
of architecture

6. Universitat
Autònoma
de Barcelona
Our proposal
6
Complete dataset,
Control Noise
Incorporate gross
anatomical
knowledge to
streamlining
Multi-Resolution approach
•Data incompleteness
•Partial
Reconstruction
•Orientation of DT-MRI
•Detail hinders
abstraction of
architecture

7. Universitat
Autònoma
de Barcelona
Completeness
7
runge-kutta integration allows Controlling
fiber estimation error and automatically
discards noisy areas (Atriums)

8. Universitat
Autònoma
de Barcelona
Vector Field Orientation
8
•Orientation does not represent
an anatomical reality, but it can change the
reconstruction by integration
•Necessary processing to use streamlining

9. Universitat
Autònoma
de Barcelona
Vector Field Orientation
9
Reorientate the stream circularly around a
virtual axis in the middle of the left ventricle:
Original Data Processed Data

10. Universitat
Autònoma
de Barcelona
Multi-Resolution
tractography
10
•Gaussian Pyramid
•“summary”
(filter+downscale)
•gaussian offers
good properties
shift, scale, and rotation
invariance. Linearity, and non
enhancement of local extrema

11. Universitat
Autònoma
de Barcelona
experiments
11
•7 ex-vivo canine hearts from JHU
Database
•2 experiments:
•Representation power of the
multi-resolution models
•Correspondence to existing
architectural model

12. Universitat
Autònoma
de Barcelona
Multi-Resolution
tractography
12
Simplified representation
Full-ScaleReduction

13. Universitat
Autònoma
de Barcelona
Multi-Resolution
tractography
13
Preservation of major fiber tendencies
Full-ScaleReduction

14. Universitat
Autònoma
de Barcelona
Architectural Model
14
HVMB
correlation

15. Universitat
Autònoma
de Barcelona
Architectural Model
14
A
A
B
B
C
C
D
D
E
E
F
f
G
G
HVMB
correlation

16. Universitat
Autònoma
de Barcelona
15
HVMB
Repeatability
Paths with
manually selecte
seed
Architectural Model

17. Universitat
Autònoma
de Barcelona
Conclusions
•Complete tractographic
reconstructions of heart anatomy
•Improved visualization of myocardial
architecture through multi-resolution
model
•Evidence of HVMB arquitectural
formation of the myocardium
16

18. Universitat
Autònoma
de Barcelona
Future Work
•Currently working on validation of
multi-resolution approach through:
•Evaluate reproduction of
geometrical properties
•preservation of important but small
details of anatomy
•Validation of the architecture through
statistical atlases
•enlarge dataset including pathologcal
cases
17

19. Multiscale Tractography for
Representing Heart Muscular
Architecture
Ferran Poveda, Debora Gil, Albert Andaluz, & Enric Marti´
Universitat
Autònoma
de Barcelona
Thank you

20. Universitat
Autònoma
de Barcelona
Full-scale correspondence
19
HVMB
correlation
Right Segment
Left Segment
Descendent Segment
Ascendent
Segment