Aline CARSIN-VU et Antoine LEGOUHY Visages team 08/06/2016

Transcription

1 Aline CARSIN-VU et Antoine LEGOUHY Visages team 08/06/2016

2 Arterial Spin Labeling (ASL) : * * * * * * 1.&Marquage& 2.&Délai& 3.&&Acquisi/on& Labelling Delay Acquisition Label Control Difference (60 repetitions) * Image courtesy I.Corouge/ C.Maumet

3 Arterial Spin Labeling (ASL) Brain perfusion changes over the growth Appropriate for pediatric imaging Biagi (2007), casl, 1,5T Taki (2011), pasl, 3T Avants (2015), pcasl, 3T

4 ROI based statistics between 6 months and 15 years (Aline) Brain perfusion template 4D (Antoine)

5 All consecutive routine brain MRI retrospectively At first 500 MRI Agreement ethical review board

6 MRI protocol: MRI 1.5 T (Magnetom Aera; Siemens Healthcare, Erlangen, Germany) MRI protocol could change depending on indications 3D T1-weighted and pulsed ASL (pasl) sequences are standardized Children could have received additional medication (i.e. chloral hydrate, nalbuphine) or general anesthesia with sevoflurane (often required between 3 and 6 years) Shanoir

7 ASL processing tools autoasl: «How does this work?» * T1 atlas registration Segmentation in GM/WM/CSF * Image courtesy I.Corouge

8 ASL processing tools autoasl: optimization for pediatric imaging * Manual suppression Parameters: - 0,4 mm - 0,2 * Huber s M-estimator * * Image courtesy I.Corougeand C.Maumet * CBF map Before CBF map After

9 ASL processing tools autoasl: adaptation for pediatric imaging * 6 months 13 years * Image courtesy I.Corouge 0-5 years In progress MNI (adult) TOM 8 (5-18 years)

10 ASL processing tools autoasl: adaptation for pediatric imaging M 0 Aslop, 2015

11 ASL processing tools autoasl: adaptation for pediatric imaging Ht, B0, oxygen saturation, T...) Wu (2010) 3T Liu (2015) 3T Aslop, 2015 : white paper

12 ASL processing tools autoasl: adaptation for pediatric imaging * Image courtesy I.Corouge

13 ASL processing tools autoasl: adaptation for pediatric imaging Mutsaerts (2013, 2015): threshold probability maps of WM and GM, 99% and 80% White matter CBF (1 subject example) Threshold Threshold Threshold Threshold

14 ASL processing tools autoasl: ROI analysis CBF in Lobes CBF map GM map AAL GM CBF map

15 Template construction: Rigid registration

16 Template construction: outline

17 Template construction: Log-euclidian framework

18 Template construction: Log-euclidian framework

19 Floating image After affine registration After non-linear registration Reference image

20 Template construction: Log-euclidian framework Computation of?

21 Template construction: Baker-Campbell-Hausdorff formula Lie bracket:

22 Template construction: using log-euclidian framework

23 Template construction: Weights

24 Template construction: example of weights

25 Template construction: example of weights

26 Floating image After affine registration After non-linear registration Reference image

27 ROI based statistic: CBF Anesthesia No anesthesia ,0 5,0 AGE 10,0 15,0 20,0

28 Optimization of ASL processing tools for pediatrics is useful: M. Proisy PhD Pediatric ASL template based on the T1 template