Invited talk at Myocardial Velocity Imaging 2011 (Leuven)

Atlas-based patterns detection.
Examples from asynchronous hearts.
Nicolas Duchateau, Mathieu De Craene,
Gemma Piella, Bart Bijnens, Alejandro Frangi

Information and Communication Technologies Department,
Universitat Pompeu Fabra, Barcelona, Spain .

Adelina Doltra, Etel Silva, Marta Sitges
Hospital Clínic de Barcelona, IDIBAPS, Spain.

Saturday, March 19, 2011

What is an atlas?

Average anatomy
+
Variation around this average

=

2


Atlas-based integrated biomarkers

Geometry

Peyrat et al., TMI 2007

Thickness Fibers Velocities Strain


Atlas-based quantification of motion abnormalities

Integrated image-based
biomarkers
Probabilistic biomarkers
Encode normality
P-value = abnormality
patient
d1 <?> d2
d1 d2
atlas

d = ???

De Craene et al. FIMH 2009


Atlas-based quantification of motion abnormalities

Atlas

Radial velocity
(mm/s)

Long. velocity
(mm/s)

Healthy subjects

Patient to study

p-value (log scale)

Duchateau et al. MEDIA 2011


How to plot p-values?
! Temporal evolution at a fixed anatomical
point

p-value (log scale)

! Local maps at fixed time t

p-value
(log scale)
Red = large abnormality



How to plot p-values?
! Spatiotemporal maps of abnormality

Time
Apex

Base

IVC Systole Diastole

p-value
(log scale)

Blue = Inward (vr<0)
Red = Outward (vr>0)



Why quantifying abnormalities? CRT context

Patient classification into specific etiologies of HF [Parsai]

" Correction of specific mechanisms of dyssynchrony conditions response

" Predicitive value of specific classes
C1= Intra
DYS Response
• Septal flash [Parsai] rate per
• Septal rebound stretch [De boeck] C2= Inter DYS
class
• Apical transverse motion [Voigt]
C3= Long AV vs. Global
C4= Short AV response
rate ?
C5= Other
Parsai et al., EHJ 2009
De Boeck et al., EJHF 2009
Voigt et al., EHJ 2009


What is a Fig.3: Septal flash mechanism
“septal flash” ? Parsai, Bijnens et al., EHJ 2009

Healthy volunteer CRT candidate with SF

4


Patient population
2D echo, 4-chamber view

21 Healthy volunteers 88 candidates OFF / ON / FU (11±2 months)
EF < 35%, QRS duration > 120ms, and (or) NYHA class III-IV

! 60 frames/s ! 30 frames/s
0.24 x 0.24 mm2 0.24 x 0.24 mm2

(in alive patients without heart transplantation)
CRT response:
Clinical 6min walking test increase " 10%
or NYHA class reduction " 1 point
Echocardiographic LV end-systolic volume reduction " 15%
14


PV-maps vs visual inspection: agreement?

Mid inferoseptal
OFF

Atlas-based
!" #$%!"
M-mode

!" !! "
#$%!" ! #$

Cohen’s Kappa = 0.88
Observed agreement = 0.94


Predictive value of SF at baseline?
Responders Response Sensitivity Specificity
rate
Total Clin. Echo. Clin. Echo. Clin. Echo. Clin. Echo.

CRT 88 72 53 0.82 0.60

SF (Visual) 55 48 44 0.87 0.80 0.67 0.83 0.56 0.69

SF (Atlas) 60 52 44 0.87 0.73 0.72 0.83 0.50 0.54

OFF
[Bleeker] Response rate
with the current guidelines:
0.7 (clinical response)
0.5 (echo response)

" Ejection fraction <35%
" QRS duration >120ms
" and/or NYHA classification III-IV)
Bleeker et al. AJC 2006


Monitor CRT outcome
Local p-value
OFF Follow-up (log scale)

CRT #9
Septal flash

CRT #8
Septal flash

CRT #12
Left-right
interaction


Blue = Inward (vp<0)
Red = Outward (vp>0)


Future work

! Extend to 3D imaging modalities (tMRI)

3D tMRI image provided by KCL, London.

Future work

! Work with the full strain tensor information

Non-responder to CRT

OFF Follow-up
3D Ultrasound images provided by Hospital Clinic, BCN. 15


Future work

! Work with the full strain tensor information

Responder to CRT

OFF Follow-up
3D Ultrasound images provided by Hospital Clinic, BCN. 16


Conclusions
! Atlas-based patterns detection
! Generic concept, extendable to other pathological patterns
and image modalities
! Automatic and reproducible analysis
! Information available at any spatiotemporal location
! Comparison OFF/Follow-up performed at the same
location
! Intrinsic notion of abnormality

! Application to CRT and Septal Flash detection
! Automatic/Visual detection in good statistical agreement
! Quantify patient evolution at follow-up
! How closer the patient gets to “normality”
! Applied to a large (88) population of patients


Acknowledgements

! Projects
! euHeart. FP7 european project
! cvREMOD. Spanish project for technology transfer

! Institutions
! Universitat Pompeu Fabra
! Hospital Clínic de Barcelona


Invited talk at Myocardial Velocity Imaging 2011 (Leuven)

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