Search results for "brain tumor"
showing 10 items of 90 documents
Gamma Knife treatment planning: MR brain tumor segmentation and volume measurement based on unsupervised Fuzzy C-Means clustering
2015
Nowadays, radiation treatment is beginning to intensively use MRI thanks to its greater ability to discriminate healthy and diseased soft-tissues. Leksell Gamma Knife® is a radio-surgical device, used to treat different brain lesions, which are often inaccessible for conventional surgery, such as benign or malignant tumors. Currently, the target to be treated with radiation therapy is contoured with slice-by-slice manual segmentation on MR datasets. This approach makes the segmentation procedure time consuming and operator-dependent. The repeatability of the tumor boundary delineation may be ensured only by using automatic or semiautomatic methods, supporting clinicians in the treatment pla…
Quantification and classification of high-resolution magic angle spinning data for brain tumor diagnosis.
2007
The goal of this work is to propose a complete protocol (preprocessing, processing and classification) for classifying brain tumors with proton high-resolution magic-angle spinning ((1)H HR-MAS) data. The different steps of the procedure are detailed and discussed. Feature extraction techniques such as peak integration, including also the automated quantitation method AQSES, were combined with linear (LDA) and non-linear (least-squares support vector machine or LS-SVM) classifiers. Classification accuracy was assessed using a stratified random sampling scheme. The results suggest that LS-SVM performs better than LDA while AQSES performs better than the standard peak integration feature extr…
Maternal medication use and the risk of brain tumors in the offspring: The SEARCH international case-control study
2006
International audience; N-nitroso compounds (NOC) have been associated with carcinogenesis in a wide range of species, including humans. There is strong experimental data showing that nitrosamides (R(1)NNO.COR(2)), a type of NOC, are potent neuro-carcinogens when administered transplacentally. Some medications are a concentrated source of amides or amines, which in the presence of nitrites under normal acidic conditions of the stomach can form NOC. Therefore, these compounds, when ingested by women during pregnancy, may be important risk factors for tumors of the central nervous system in the offspring. The aim of the present study was to test the association between maternal use of medicat…
Treatment of early childhood medulloblastoma by postoperative chemotherapy and deferred radiotherapy
2008
To investigate the utility of postoperative chemotherapy in delaying radiotherapy and to identify prognostic factors in early childhood medulloblastoma, we studied children younger than 3 years of age registered to the HIT-SKK'87 (Therapieprotokoll für Säuglinge und Kleinkinder mit Hirntumoren [Brain Tumor Radiotherapy for Infants and Toddlers with Medulloblastoma] 1987) trial who received systemic interval chemotherapy until craniospinal radiotherapy was applied at 3 years of age or at relapse, from 1987 to 1993. Children with postoperative residual tumor or metastatic disease received systemic induction chemotherapy prior to interval chemotherapy. Twenty-nine children were eligible for an…
Imaging of Orthotopic Glioblastoma Xenografts in Mice Using a Clinical CT Scanner: Comparison with Micro-CT and Histology
2016
Purpose There is an increasing need for small animal in vivo imaging in murine orthotopic glioma models. Because dedicated small animal scanners are not available ubiquitously, the applicability of a clinical CT scanner for visualization and measurement of intracerebrally growing glioma xenografts in living mice was validated. Materials and Methods 2.5x106 U87MG cells were orthotopically implanted in NOD/SCID/ᵞc-/- mice (n = 9). Mice underwent contrast-enhanced (300 μl Iomeprol i.v.) imaging using a micro-CT (80 kV, 75 μAs, 360° rotation, 1,000 projections, scan time 33 s, resolution 40 x 40 x 53 μm) and a clinical CT scanner (4-row multislice detector; 120 kV, 150 mAs, slice thickness 0.5 …
Gliofibromas (including malignant forms), and gliosarcomas: a comparative study and review of the literature
1993
The presence of connective tissue elements in gliomas necessitates in every case a thorough analysis of the character and derivation of such elements to allow the formulation of an appropriate diagnosis. Four cases are presented in this paper. In cases 1 and 2 (anaplastic astrocytomas in two children, 9 and 4 years old, respectively) all the neoplastic elements were astrocytes and their ability to produce or indirectly promote the production of reticulin and collagen fibers accounted for the presence of such elements in close association with the tumor cells. The term "gliofibroma" has been coined for such tumors, but "desmoplastic astrocytoma", (low grade or anaplastic) or in highly malign…
Sub-cellular tumor identification and markerless differentiation in the rat brain in vivo by multiphoton microscopy
2012
Objective/Background Aim of the current study was to localize and differentiate between tumor (glioma) and healthy tissue in rat brains on a cellular level. Near-infrared multiphoton microscopy takes advantage of the simultaneous absorption of two or more photons to analyze various materials such as cell and tissue components via the observation of endogenous fluorophores such as NAD(P)H, FAD, porphyrins, melanin, elastin, and collagen, with a very high resolution, without inducing the problems of photo-bleaching on out-of-focus areas. Methods In vitro and in vivo studies on healthy rat brains as well as C6 glioma cell line allografts have been performed. Near-infrared laser pulses (λ = 690…
Flow-cytometric DNA analysis of intracranial tumors in children.
2004
The objective of this study was to investigate flow-cytometric DNA values of pediatric intracranial tumors, and to establish DNA analysis as a potential prognostic parameter. Twenty-nine brain tumor specimens from 26 pediatric patients were cryo-preserved within a 3-year period. The DNA content was measured by flow cytometry. Six of the tumor specimens had aneuploid DNA patterns. The median of the proliferation index was lower in the survivor group compared with the non-survivor group (36.4% and 47.5%, respectively). Ten of the 26 patients are still alive, eight were lost to follow up, and eight died. Flow-cytometric DNA analysis may be a helpful tool for examining brain tumors in children.…
The triad hsp60-mirnas-extracellular vesicles in brain tumors: Assessing its components for understanding tumorigenesis and monitoring patients
2021
Brain tumors have a poor prognosis and progress must be made for developing efficacious treatments, but for this to occur their biology and interaction with the host must be elucidated beyond current knowledge. What has been learned from other tumors may be applied to study brain tumors, for example, the role of Hsp60, miRNAs, and extracellular vesicles (EVs) in the mechanisms of cell proliferation and dissemination, and resistance to immune attack and anticancer drugs. It has been established that Hsp60 increases in cancer cells, in which it occurs not only in the mitochondria but also in the cytosol and plasma-cell membrane and it is released in EVs into the extracellular space and in cir…
Multiproject–multicenter evaluation of automatic brain tumor classification by magnetic resonance spectroscopy
2008
[EN] Automatic brain tumor classification by MRS has been under development for more than a decade. Nonetheless, to our knowledge, there are no published evaluations of predictive models with unseen cases that are subsequently acquired in different centers. The multicenter eTUMOUR project (2004-2009), which builds upon previous expertise from the INTERPRET project (2000-2002) has allowed such an evaluation to take place. A total of 253 pairwise classifiers for glioblastoma, meningioma, metastasis, and low-grade glial diagnosis were inferred based on 211 SV short TE INTERPRET MR spectra obtained at 1.5 T (PRESS or STEAM, 20-32 ms) and automatically pre-processed. Afterwards, the classifiers …