Post on 25-Jun-2015
description
Atlas-based Quantication of Myocardial MotionAbnormalities: Added-value for theUnderstanding of CRT Outcome?
STACOM-CESC Workshop, MICCAI 2010Beijing– 20/09/2010
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Atlas-based quantification of motion abnormalities
Healthy subjects
Radial velocity
Long. velocity
Atlas
variance
average
(mm/s)
(mm/s)
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Atlas-based quantification of motion abnormalities
Radial velocity
Long. velocity
Atlas
d = ???
Healthy subjects
Patient to study
p-value (log scale)
(mm/s)
(mm/s)
New quantitative indexes [quantification of motion abnormalities]
Statistical atlas Automatic Reproducible
Contributions
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In this work: Mechanisms involved in CRT response Quantification before and after the therapy
Added-value for clinical studies Accurate, automatic Generic methods applicable to almost any
imaging modality studied parameter and mechanism
[1] Stellbrink et al. , EHJ Suppl. 2004 [5] Parsai et al., EHJ 2009 [2] Chung et al. , Circulation 2008 [6] De Boeck et al., EJHF 2009[3] Fornwalt et al. , JASE 2009 [7] Voigt et al., EHJ 2009[4] Voigt, EHJ 2009
Lack of reproducibility in large scale studies [1]
Is there a “universal” index? [2,3,4]
Changing the strategy?
Patient classification into specific etiologies of HF [5]
Correction of specific mechanisms of dyssynchrony conditions response
Predicitive value of specific classes
• Septal flash [5]
• Septal rebound stretch [6]
• Apical transverse motion [7]
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Why quantifying abnormalities? CRT context
Need to accurately characterize these patterns
Fig.3: Septal flash mechanismWhat is a “septal flash” ?
Healthy volunteer CRT candidate with SF
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Parsai, Bijnens et al., EHJ 2009
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Effect of CRT on septal flash
Pre-CRT Follow-up (6 months)
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3
Effect of CRT on septal flash
Pre-CRT Follow-up (6 months)
Pre-CRT
5
3
Effect of CRT on septal flash
Follow-up(6 months)
Pre-CRT Follow-up (6 months)
Pre-CRT
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Plan
Atlas pipeline
Relevance of the atlas population
Clinical outcome after CRT
Healthy subjects
Atlas of “normality”
Registration-based tracking
Spatio-temporal
normalization
Group statistics: average, covariance, …
Myocardial velocities
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[9] Duchateau et al. , MICCAI 2009
Construction of an atlas of “normality”[9]
Healthy subjects
Atlas of “normality”
Registration-based tracking
Group statistics: average, covariance, …
8b
[9] Duchateau et al. , MICCAI 2009
Construction of an atlas of “normality”[9]
Normalized timescaleInital ECG
Temporal normalization
Spatio-temporal
normalization
Healthy subjects
Atlas of “normality”
Registration-based tracking
Group statistics: average, covariance, …
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[9] Duchateau et al. , MICCAI 2009
Construction of an atlas of “normality”[9]
Spatio-temporal
normalization
Spatial reorientation
Atlas of “normality”
Population of CRT
candidates
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Statistical distance to “normality”
Healthy subjects
d = ???
Statistical distance = p-value associated to Mahalanobis distance
LOW p-value = HIGH abnormality
Plan
Atlas pipeline
Relevance of the atlas population
Clinical outcome after CRT
2D echo, 4-chamber view
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Data available
21 Healthy volunteers
60 frames/s0.24 x 0.24 mm2
88 candidates OFF / ON / FU (11+/- 2 months)EF < 35%, QRS duration > 120ms, and (or) NYHA class III-IV
60 frames/s0.24 x 0.24 mm2
CRT response:Clinical 6min walking test increase ≥ 10%
Echocardiographic LV end-systolic volume reduction ≥ 15% or NYHA class reduction ≥ 1 point
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Is the atlas representative of “normality”?
• Non-dilated hearts• No antecedent of cardiac dysfunction• Normal baseline characteristics• Young (30 +/- 5)
How many subjects?
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Is the atlas representative of “normality”?
• Non-dilated hearts• No antecedent of cardiac dysfunction• Normal baseline characteristics• Young (30±5)
How many subjects?
Statistical distribution assumption
d = ???
Statistical distance = p-value associated to Mahalanobis distance
Gaussianity tests:Shapiro-Wilk (SW) and Lilliefors (LF)
Plan
Atlas pipeline
Relevance of the atlas population
Clinical outcome after CRT
Inward Outward
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Data representation
Temporal evolution at a fixed anatomical point
p-value (log scale)
Local maps at fixed time t
p-value (log scale)
Red = large abnormality
Data representation
Spatiotemporal maps of abnormality
Blue = Inward (vp<0)Red = Outward (vp>0)
Base
ApexTime
IVC Systole Diastole
Inward Outward
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p-value (log scale)
Spatiotemporal quantification of abnormalities
CRT #9Septal flash
CRT #8Septal flash
CRT #12Left-right
interaction
15a
Blue = Inward (vp<0)Red = Outward (vp>0)
Local p-value * sign of radial velocity
(log scale)
???
IVC Systole Diastole
OFF
Follow-up
Spatiotemporal quantification of abnormalities
CRT #9Septal flash
CRT #8Septal flash
CRT #12Left-right
interaction
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Blue = Inward (vp<0)Red = Outward (vp>0)
IVC Systole Diastole
OFF Follow-upLocal p-value * sign of
radial velocity(log scale)
Reduction of specific abnormalities (SF)
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Correction of SF = High predictive value
p-value(log scale)
Conclusions
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Added-value for clinical studies Accurate, automatic Information still available at every location (x,t) [not heart segments only] Generic methods applicable to almost any
imaging modality studied parameter and mechanism
Clinical conclusionsSimilar observations than in previous clinical studies [5,6]
Observation of global abnormalities leads to limited conclusions
Correction of specific abnormalities (e.g. SF) = high predictor of response
Further work = extension to strain measurements (influence of local infarction)
[5] Parsai et al., EHJ 2009[6] Parsai et al., EHJ 2009
CISTIB, Universitat Pompeu Fabra Image registration team M. De Craene, G. Piella
Hospital Clínic, Barcelona E. Silva, A. Doltra, M. Sitges, B. H. Bijnens
Acknowledgements
Related worksAtlas construction: N. Duchateau, M. De Craene, E. Silva, M. Sitges, B. H. Bijnens, and A. F. Frangi “Septal Flash Assessment on CRT Candidates based on Statistical Atlases of Motion” MICCAI’09 LNCS 5762 (pp.759-766)
Quantification of CRT outcome: N. Duchateau, A. Doltra, E. Silva, M. De Craene, G. Piella, L. Mont, Ma A. Castel, J. Brugada, M. Sitges, and A. F. Frangi “Added value of a statistical atlas-based quantification of motion abnormalities for the prediction of CRT response” EuroEcho 2010 Randers – Lecture rooms – 09/12/2010
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