Convex non-negative matrix factorization for brain tumor delimitation from MRSI data
Ortega-Martorell, Sandra (Universitat Autònoma de Barcelona. Institut de Biotecnologia i de Biomedicina "Vicent Villar Palasí")
Lisboa, P. J. G. (Liverpool John Moores University. Department of Mathematics and Statistics)
Vellido, Alfredo (Universitat Politècnica de Catalunya. Departament de Llenguatges i Sistemes Informàtics)
Simoes, Rui Vasco (Memorial Sloan Kettering Cancer Center)
Pumarola i Batlle, Martí (Universitat Autònoma de Barcelona. Departament de Medicina i Cirurgia Animals)
Julià Sapé, Ma. Margarita (Universitat Autònoma de Barcelona. Departament de Bioquímica i de Biologia Molecular)
Arús i Caraltó, Carles (Universitat Autònoma de Barcelona. Departament de Bioquímica i de Biologia Molecular)

Data:	2012
Resum:	Background: Pattern Recognition techniques can provide invaluable insights in the field of neuro-oncology. This is because the clinical analysis of brain tumors requires the use of non-invasive methods that generate complex data in electronic format. Magnetic Resonance (MR), in the modalities of spectroscopy (MRS) and spectroscopic imaging (MRSI), has been widely applied to this purpose. The heterogeneity of the tissue in the brain volumes analyzed by MR remains a challenge in terms of pathological area delimitation. Methodology/Principal Findings: A pre-clinical study was carried out using seven brain tumor-bearing mice. Imaging and spectroscopy information was acquired from the brain tissue. A methodology is proposed to extract tissue type-specific sources from these signals by applying Convex Non-negative Matrix Factorization (Convex-NMF). Its suitability for the delimitation of pathological brain area from MRSI is experimentally confirmed by comparing the images obtained with its application to selected target regions, and to the gold standard of registered histopathology data. The former showed good accuracy for the solid tumor region (proliferation index (PI)>30%). The latter yielded (i) high sensitivity and specificity in most cases, (ii) acquisition conditions for safe thresholds in tumor and non-tumor regions (PI>30% for solid tumoral region; ≤5% for non-tumor), and (iii) fairly good results when borderline pixels were considered. Conclusions/Significance: The unsupervised nature of Convex-NMF, which does not use prior information regarding the tumor area for its delimitation, places this approach one step ahead of classical label-requiring supervised methods for discrimination between tissue types, minimizing the negative effect of using mislabeled voxels. Convex-NMF also relaxes the non-negativity constraints on the observed data, which allows for a natural representation of the MRSI signal. This should help radiologists to accurately tackle one of the main sources of uncertainty in the clinical management of brain tumors, which is the difficulty of appropriately delimiting the pathological area.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Cervell ; Tumors ; Tumores cerebrales ; Brain tumours
Publicat a:	PloS one, Vol. 7, Issue 10 (October 2012) , p. e47824, ISSN 1932-6203

DOI: 10.1371/journal.pone.0047824
PMID: 23110107

17 p, 1.5 MB

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Documents de recerca > Documents dels grups de recerca de la UAB > Centres i grups de recerca (producció científica) > Ciències de la salut i biociències > Institut de Biotecnologia i de Biomedicina (IBB)
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