Intérêt de l’IRM, avec séquences de diffusion, de perfusion et de la spectrométrie dans le diagnostic et la surveillance de gliomes d’aspect initial de grade 2 : recherche de marqueurs radiologiques orientant vers une aggravation tumorale de grade

[Multimodal magnetic resonance imaging of brain tumors]

Magnetic resonance imaging arose as a reference for diagnosis, pre-therapeutic and follow-up of brain tumors. Among parameters obtained from standard MRI (of low specificity), only volumetric growth allows prognostic information. The multiple "advanced" sequences have leaded to increase both sensitivity and specificity of brain MRI. Yet, perfusion-weighted imaging and spectroscopy provide metabolic information, and diffusion tensor imaging and cortical activation provide functional information. Characterization, grading, therapeutic management and follow-up have improved, with prognostic information.

[Advances in adults' gliomas biology, imaging and treatment]

A better understanding of gliomas biology is now leading to a combined histo-molecular classification of these tumors. In anaplastic gliomas ongoing studies depend on 1p/19q codeletion status and in glioblastomas on MGMT methylation status. Advanced brain tumor imaging elicits a better identification of gliomas evolutive potential of. In low-grade gliomas, the importance of maximal resection and the role of chemotherapy are being increasingly recognized. In anaplastic gliomas, phase III studies have clarified the respective roles of chemotherapy and radiotherapy. In glioblastomas concomitant chemoradiotherapy is the standard. Most targeted therapies, namely anti-EGFR therapies have failed to demonstrate efficacy but anti-angiogenics are promising. The aim of this review is to discuss the main advances in adults' gliomas biology, imaging and treatment.

Evolution of brain tumor and stability of geometric invariants

This paper presents a method to reconstruct and to calculate geometric invariants on brain tumors. The geometric invariants considered in the paper are the volume, the area, the discrete Gauss curvature, and the discrete mean curvature. The volume of a tumor is an important aspect that helps doctors to make a medical diagnosis. And as doctors seek a stable calculation, we propose to prove the stability of some invariants. Finally, we study the evolution of brain tumor as a function of time in two or three years depending on patients with MR images every three or six months.