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Search Results: 1 - 10 of 6198 matches for " Brain Tumors "
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Magnetic Resonance Perfusion in Brain Tumors: Comparison of Different Evaluation Approaches in Dual-Echo and Multi-Echo Techniques  [PDF]
Volker Hietschold, Andrij Abramyuk, Tareq Juratli, Kerim Hakan Sitoci-Ficici, Michael Laniado, Jennifer Linn
International Journal of Medical Physics,Clinical Engineering and Radiation Oncology (IJMPCERO) , 2017, DOI: 10.4236/ijmpcero.2017.62016
Abstract: Dynamic measurements of T1 shortening (dynamic contrast enhanced—DCE) as well as of T2* shortening (dynamic susceptibility contrast—DSC) as two separate measurement strategies are widely used to quantitatively describe tumor perfusion and vascularity. Dual-echo approaches allow for the simultaneous assessment of both effects. The extension to multi-echo sequences should inhere the advantage of improved signal-to-noise ratios and more precise sampling of the T2* decay. The aim of our study is to investigate, if an extension of the dual-echo approach to the multi-echo approach allows for more stable quantitative determination of pharmacokinetic parameters in brain tumors. This study applies a multi-echo approach to obtain different estimations of a vascular input function and analyzes various combinations of vascular input functions and pharmacokinetic models. Perfusion measurements were performed with 52 consecutive patients with different brain tumors using a 10-echo gradient echo sequence. Our findings show that the extension to multi-echo sequences leads to an 11%-improvement of the Contrast-to-Noise ratio. Compared to other combinations, an application of Extended Tofts model using the T2*-related venous output function or an output function estimated in the tumor tissue enables the most reliable determination of perfusion parameters, reducing the reproducibility range by a factor of 1.2 to 10 for Ktrans and of 1.2 to 5.5 in the case of rBV calculation. Determination of Ktrans within repeated measurements within about 3 days results as most stable, if AIF from tumor pixels is used as vascular input function, meaning that the scatter is reduced by a factor of 1.2 compared to the next best VIF and by a factor of 10 compared to the worst of the tested approaches. In addition, this study shows that signal decomposition into two components with different Larmor frequencies might provide additional information concerning tissue composition of brain tumors.
Technological Progress in Radiation Therapy for Brain Tumors  [PDF]
Frederik Jozef Vernimmen, Kathy Rock
Journal of Cancer Therapy (JCT) , 2014, DOI: 10.4236/jct.2014.51005
Abstract:

To achieve a good therapeutic ratio the radiation dose to the tumor should be as high as possible with the lowest possible dose to the surrounding normal tissue. This is especially the case for brain tumors. Technological advancements in diagnostic imaging, dose calculations, and radiation delivery systems, combined with a better understanding of the pathophysiology of brain tumors have led to improvements in the therapeutic results. The widely used technology of delivering 3-D conformal therapy with photon beams (gamma rays) produced by Linear Accelerators has progressed into the use of Intensity modulated radiation therapy (IMRT). Particle beams have been used for several decades for radiotherapy because of their favorable depth dose characteristics. The introduction of clinically dedicated proton beam therapy facilities has improved the access for cancer patients to this treatment. Proton therapy is of particular interest for pediatric malignancies. These technical improvements are further enhanced by the evolution in tumor physiology imaging which allows for improved delineation of the tumor. This in turn opens the potential to adjust the radiation dose to maximize the radiobiological effects. The advances in both imaging and radiation therapy delivery will be discussed.

Epidemiology of Tumors of the Brain and Central Nervous System: Review of Incidence and Patterns among Histological Subtypes  [PDF]
Dimitris Vovoras, Keshav P. Pokhrel, Chris P. Tsokos
Open Journal of Epidemiology (OJEpi) , 2014, DOI: 10.4236/ojepi.2014.44029
Abstract: Most epidemiology reports indicate that brain tumor rates in whites are higher than other populations and that they are more common in males than females. In this report, we analyze incidence patterns in registry data from the Surveillance, Epidemiology, and End Results program in different histological groups, racial/gender combinations and compare the overall and age-specific incidence rates. Our analysis shows statistically significant racial differences in rates for astrocytomas non-otherwise specified in both sexes, and unspecified malignant intracranial intraspinal neoplasms for females. Those of other specified intracranial and intraspinal neoplasms in females are higher than males, indicating the importance of biological differences. Other glioma young age rates peak after the age of five, the peak is higher for the black race. The study demonstrated several distinctive patterns in the rates by histological subtypes and showed differentiation in the age at diagnosis, giving insight on potential true changes in different subpopulations.
Epigenetic alterations in human brain tumors in a Brazilian population
Anselmo, Nilson Praia;Bello, Maria Josefa;Gonzalez-Gomez, Pilar;Dias, Luis Antonio Araújo;Almeida, José Reinaldo Walter de;Santos, Marcelo José dos;Rey, Juan A.;Casartelli, Cacilda;
Genetics and Molecular Biology , 2006, DOI: 10.1590/S1415-47572006000300001
Abstract: aberrant methylation of cpg islands located in promoter regions represents one of the major mechanisms for silencing cancer-related genes in tumor cells. we determined the frequency of aberrant cpg island methylation for several tumor-associated genes: dapk, mgmt, p14arf, p16ink4a, tp73, rb1 and timp-3 in 55 brain tumors, consisting of 26 neuroepithelial tumors, 6 peripheral nerve tumors, 13 meningeal tumors and 10 metastatic brain tumors. aberrant methylation of at least one of the seven genes studied was detected in 83.6% of the cases. the frequencies of aberrant methylation were: 40% for p14arf, 38.2% for mgmt, 30.9% for, p16ink4a, 14.6% for tp73 and for timp-3, 12.7% for dapk and 1.8% for rb1. these data suggest that the hypermethylation observed in the genes p14arf, mgmt and p16ink4a is a very important event in the formation or progression of brain tumors, since the inactivation of these genes directly interferes with the cell cycle or dna repair. the altered methylation rate of the other genes has already been reported to be related to tumorigenesis, but the low methylation rate of rb1 found in tumors in our sample is different from that so far reported in the literature, suggesting that perhaps hypermethylation of the promoter is not the main event in the inactivation of this gene. our results suggest that hypermethylation of the promoter region is a very common event in nervous system tumors.
Pediatric brain tumors: Diagnostic and treatment
Nikitovi? M.R.,Golubi?i? I.V.,Borojevi? N.D.,Pekmezovi? T.D.
Acta Chirurgica Iugoslavica , 2009, DOI: 10.2298/aci0904019n
Abstract: During the period 1995-2004 we treated 212 patients (pts) with brain tumors. There were 133 boys and 79 girls, aged from 2,5 yrs up to 18 yrs (Me=9,7 yrs). The majority of pts were in age group (4-16) yrs-179 pts. Supratentorial tumors were diagnosed in 118 pts vs. infratentorial 94 pts. Therapy involved surgery, postoperative radiotherapy with or without chemotherapy. Survival rates were calculated using Caplan-Meier method and differences between curves with log-rank test. During the follow-up period from 1 to 9 year (Me=3 yrs) 5-year disease free survival rate was 55,7%. 79 pts failed to therapy. There was no statistically significant difference in survival according to sex (p=0,123) and age (p=0,367). Pts with supratentorial tumors had statistically significant better survival (p=0,036). Pts with histologic type lowgrade astrocitomas had statistically significant better survival than malignant gliomas, ependymomas and PNET (p=0,0001). Surgery, postoperative radiotherapy and chemotherapy in selected cases are efficient therapeutic approach for pediatric brain tumors.
Description of Hemoproteins and Elemental Homeostasis in Brain Tumors  [PDF]
E. I. Erlykina, L. M. Obukhova, I. A. Medyanik, K. S. Yashin, V. G. Pimenov, I. I. Evdokimov, O. V. Barinova, A. B. Yazykova
Journal of Biosciences and Medicines (JBM) , 2018, DOI: 10.4236/jbm.2018.65010
Abstract: The role of element homeostasis in neoplastic disease pathogenesis is be-yond question. The imbalance of trace elements precisely underlies the ini-tiation and promotion of tumor pathology. The aim of the study was to in-vestigate blood and tissue macroelements, microelements and hemoproteins level in brain tumors and their intermolecular interactions. Samples of blood and brain tumor tissues were investigated. Detection of myoglobin level was implemented by the reaction of passive hemagglutination and immunoturbidimetric test. Catalase activity was determined by the method of Beer and Sizer. Free radical activity was determined by the method of induced biochemiluminescence. Microelements level was investigated by usage of atomic emission spectrometry. To build the networks of studied hemoprotein interactions with signaling pathways of proteins, expressed in brain tumors, molecular interaction databases (STRING, BioGrid) were used. Modern databases of signaling pathways (KEGG) suggest that in normal cells hypoxia can lead to HIF-1A protein synthesis. ROS synthesis inhibits the PHD enzyme and triggers the release of calcium ions, and increases proliferation. Calcium ions are triggering factor of apoptosis and cell proliferation. Myoglobin can possibly be the cell adaptation factor towards hypoxia, oxidative stress and element homeostasis violation, and myoglobin level decreasing can additionally stimulate proliferation, by apoptosis inhibition.
Astroblastoma: A radio-histological diagnosis
Kurwale Nilesh,Agrawal Deepak,Sharma Bhawani
Journal of Pediatric Neurosciences , 2008,
Abstract: Astroblastoma is thought to arise from astroblast - an intermittent cell between spongioblast and astrocytes and is a rare tumor in the pediatric age group. The histological appearance are characterized by radiating arrangement of spindle-shaped tumor cells forming perivascular pseudorosettes, and being very similar to that seen in ependymomas, makes differentiation difficult. The authors report the case of a 5-year-old girl who had a large frontal tumor, which was thought to be an astroblastoma preoperatively, based on the unique magnetic resonance imaging features these tumors have. The histological findings, in association with the preoperative radiology confirmed the diagnosis of astroblastoma. The authors conclude that the MR imaging of astroblastomas is extremely helpful in differentiating from ependymomas and is used for preparing the histopathology reports in these patients.
The Association between Cellular Phone Usage and Brain Neoplasms  [PDF]
Rohit Chander Chopra
Occupational Diseases and Environmental Medicine (ODEM) , 2016, DOI: 10.4236/odem.2016.44011
Abstract: Background: The association between cellular phones and brain tumors is a question that is frequently asked of the medical and scientific community. The prevalence of cell phone use and the significant morbidity and mortality of brain tumors contribute to this pairing. Cell phones are known to emit radio frequency energy in the form of both ionizing and non-ionizing radiation. Ionizing radiation is known to be within X-rays, which do have an association with cancer. Objective: To assess if the use of the cell phone has an association with brain tumors. Methods: The searches performed through PubMed were conducted to find studies that sought to provide evidence as to whether or not increased cell phone exposure contributed to the development of brain tumors. Also searched for was increased regional metabolism of the brain with the use of the cell phone switched in the on position. Studies were restricted to being published during or after the year 2000 and presented in the English language. Results: The studies largely support the conclusion that cell phone usage does not lead to the development of brain cancer. Studies employed different strategies, such as the prospective cohort and case-control studies to reach this conclusion. Both studies failed to show statistically significant evidence that cell phones were associated with brain tumors of the central nervous system. Conclusions: Questions raised by crossover studies demonstrating increased regional brain glucose metabolism continue to remain largely unanswered by current research and remain a starting point for future research. The prevalence of the issue strengthens its position among others as a matter that the medical community must continue to address to meet the needs of an increasingly exposed patient population. The overall hypothesis that cell phone usage does not lead to the development of brain tumors was supported.
Tectal plate tumors
Lázaro, Bruno C.R.;Landeiro, José A.;
Arquivos de Neuro-Psiquiatria , 2006, DOI: 10.1590/S0004-282X2006000300015
Abstract: tectal plate is a rare location for a tumor. many papers have described different types of pathology arising in that location including tumors, vascular lesions, inflamatory and infectious processes. in this paper we describe our experience in treating seven patients with tectal plate lesions, with different ages and types of pathology: five patients presented with low grade gliomas, one with lung cancer metastasis and the last presenting with a tectal plate cavernoma. open surgery was performed in three cases (due to tumor enlargement or need for the exact diagnosis). in the other cases, the treatment of non-comunicating hydrocephalus was the only treatment employed. the prognosis is of course dependent on the underlining pathology. in our series, except in the metastatic tumor case and the cavernoma, the other types of lesion consisted of low grade gliomas. these lesions represent a different type of brain stem tumor sharing a common good prognosis, with a benign behavior. we believe that tectal tumors must be managed case by case. when a patient presents with a benign lesions in the tectal region, treating the main symptom - hydrocephalus - should be the first attempt in management of these lesions.
Neurological evaluation of children and adolescents with brain tumor, based on ambulatory-oriented follow-up
Serafim, Alexandre;Vilanova, Luiz Celso Pereira;Silva, Najla Saba;
Arquivos de Neuro-Psiquiatria , 2001, DOI: 10.1590/S0004-282X2001000600003
Abstract: taken as proved that brain tumors are the second most frequent childhood neoplasm - only outnumbered by leukemias - we have undertaken a clinical perspective study with seventy brain tumor patients ranging from one to fifteen years of age, throughout a four-year period (1993-1997), based on ambulatory-oriented follow-up. forty-one male and twenty-nine female patients were analyzed, in that a slightly higher number of infratentorial tumors was observed (thirty-eight cases), compared to those supratentorially located (thirty-two cases). the most repeatedly observed during the study was the medulloblastoma (twenty-one patients), followed by the astrocytoma (fifteen patients) and the germinoma (eleven patients). it should be pointed out that during the ambulatory follow-up 75,5% of patients developed neurological sequels. a tumor recurrence was noticed in 34,3% of them, while 21,4% eventually died.
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