Activités scientifiques

Activités scientifiques

Ateliers et conférences à venir (1)

Séminaire à venir (1)

Ateliers et conférences passés (9)

Séminaires passés (4)

Ateliers et conférences
(à venir)

MAIN 2018: Montréal Intelligence artificielle & neuroscience. De l’intelligence des machines à la science des cerveaux

9 et 10 décembre: Salle K-500, campus de l’Université de Montréal
9 au 12 décembre 2018

Pierre Bellec (Université de Montréal)
Andrea Green (Université de Montréal)
Karim Jerbi (Université de Montréal)
Guillaume Lajoie (Université de Montréal)
Jean-Marc Lina (École de technologie supérieure)
Bratislav Misic (Montréal Neurological Institute (MNI))
Pascal Vincent (Université de Montréal)
Site Web :

(à venir)

Le jeudi 17 janvier 2019 – 12:00 – 13:30
Séminaire Physnum
CRM, UdeM, Pav. André-Aisenstadt, 2920, ch. de la Tour, salle 4336

Fractal Analysis of Mammographic Brest Lesions and Characterization of Loss of Tissue Homeostasis in Tumor Microenvironment

André Khalil, University of Maine, Orono

The current breast cancer projects in my lab investigate individual breast tumors, as well as their microenvironment, through mammography.
Several studies show that malignant tumor growth may develop in fractal patterns. We used the 2D Wavelet-Transform Modulus Maxima (WTMM) method to estimate the 3D fractal structure of breast lesions—in this case, microcalcification clusters—by pairing the information from two separate 2D-projected mammographic views of the same breast. 92%
of malignant breast lesions studied were fractal, while 88% of the benign lesions were Euclidean (non-fractal). These results support the notion that the fractal structure of malignant tumors is more likely to be associated with an invasive behavior into the surrounding tissue compared to the less invasive, Euclidean structure of benign tumors.
The multicellular architecture and organization of the ductal tree of the mammary glandhas coherent cellular movement within an extracellular matrix cocoon that guides formation of structural units of tissues important for quiescence and homeostasis. This motivated us to “think outside the tumor”. We verified the hypothesis that this disruption of coherent angular motion, and the consequential adoption of randomized motility associated to malignant transformation, is a physical phenomenon that we can characterize quantitatively via the roughness fluctuation analysis of mammographic microenvironment tissue. When compared to normal tissue environment, the tissue in the microenvironment of tumors is disrupted, as quantified via the 2D WTMM method. The density fluctuations in healthy mammographic breast tissue, characterized by their surface roughness by the Hurst exponent, H, is either H~1/3 (high roughness) for fatty tissue or H~2/3 (low roughness) for dense tissue. However, increasing numbers of tissue regions with H~1/2 were found surrounding tumors. We infer that the underlying physical processes associated with breast tumors have a H~1/2 signature, which indicates randomness, lack of spatial correlation, and free diffusion.

Ateliers et conférences

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Date Titre Lieu Participants
2003/10/30 – 2003/10/31 Workshop on Cerebral Plasticity : Imaging and Modelling CRM 84
2005/03/31 – 2005/04/02 Workshop on Bayesian Inference and Functional Brain mapping CRM 30
2005/10/17 – 2005/10/18 Workshop on mathematics in brain imaging and their applications to cognitive and clinical neurosciences IUGM
2006/05/11 – 2006/05/12 Current Issues in functional imaging with optical devices CRM 80
2006/05/23 – 2006/05/23 Workshop between specialists of Brain and Spine Imaging and mathematicians interested in the questions arising from imaging CRM 15
2008/06/04 – 2008/06/04 Workshop on Signal Processing Methods in Brain Imaging Institut universitaire de gériatrie de Montréal
2013/10/21 – 2013/10/24 Workshop on Scale-free Dynamics and Networks in Neurosciences CRM 82
2017/06/12 – 2017/06/14 Translational-Oriented Quantitative Theurapeutic Approaches: A Concerted Effort Université de Montréal 9
2017/11/18 – 2017/11/21 MAIN 2017: Artificial Intelligence & Neuroscience CRM 242


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Date Conférencier Titre Type
2004/06/03 Valérie Girardin, Laboratoire SCAD, Universite de Caen, France Sur l’entropie pour des chaînes de Markov, semi-markoviennes et cachées Conférence Physnum
2004/11/25 Line Garnero, Laboratoire de Neurosciences Cognitives et Imagerie Cérébrale, Hôpital La Salpetrière, FRANCE Imagerie dynamique de la connectivité corticale en MEG : méthodes et applications à la rivalité binoculaire Séminaire Physnum
2011/05/31 Alain Arnéodo, École Normale Supérieure de Lyon A wavelet-based multiscale methodology to detect replication origins in the human genome Séminaire Physnum
2017/07/25 Bourama Toni, Virginia State and Brown University Nash Limit Cycles in the dynamics of America socio-cultural evolution: A game-theoretical approach Séminaire Physnum