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PURPOSE: Noninvasive methods are desired to predict the treatment response to Stereotactic Radiosurgery (SRS) to improve individual tumor management. In a previous study, we demonstrated that Diffusion Tensor Imaging (DTI)-derived parameter maps significantly correlate to SRS response. This study aimed to analyze and compare the predictive value of intratumoral ADC and DTI parameters in patients with meningiomas undergoing radiosurgery. METHODS: MR images of 70 patients treated with Gamma Knife SRS for WHO grade I meningiomas were retrospectively reviewed. MR acquisition included pre- and post-treatment DWI and DTI sequences, and subtractions were calculated to assess for radiation-induced changes in the parameter values. RESULTS: After a mean follow-up period (FUP) of 52.7 months, 69 of 70 meningiomas were controlled, with a mean volume reduction of 34.9%. Whereas fractional anisotropy (FA) values of the initial exam showed the highest correlation to tumor volume change at the last FU (CC = - 0.607), followed by the differences between first and second FU values of FA (CC = - 0.404) and the first longitudinal diffusivity (LD) value (CC = - 0.375), the correlation coefficients of all ADC values were comparably low. Nevertheless, all these correlations, except for ADC measured at the first follow-up, reached significance. CONCLUSION: For the first time, the prognostic value of ADC maps measured in meningiomas before and at first follow-up after Gamma Knife SRS, was compared to simultaneously acquired DTI parameter maps. Quantities assessed from ADC maps present significant correlations to the volumetric meningioma response but are less effective than correlations with DTI parameters.
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Neoplasias Meníngeas , Meningioma , Radiocirurgia , Humanos , Meningioma/diagnóstico por imagem , Meningioma/radioterapia , Meningioma/cirurgia , Imagem de Tensor de Difusão/métodos , Radiocirurgia/métodos , Estudos Retrospectivos , Neoplasias Meníngeas/diagnóstico por imagem , Neoplasias Meníngeas/radioterapia , Neoplasias Meníngeas/patologiaRESUMO
PURPOSE: This report presents the first investigation of the radiomics value in predicting the meningioma volumetric response to gamma knife radiosurgery (GKRS). METHODS: The retrospective study included 93 meningioma patients imaged by three Tesla MRI. Tumor morphology was quantified by calculating 337 shape, first- and second-order radiomic features from MRI obtained before GKRS. Analysis was performed on original 3D MR images and after their laplacian of gaussian (LoG), logarithm and exponential filtering. The prediction performance was evaluated by Pearson correlation, linear regression and ROC analysis, with meningioma volume change per month as the outcome. RESULTS: Sixty calculated features significantly correlated with the outcome. The feature selection based on LASSO and multivariate regression started from all available 337 radiomic and 12 non-radiomic features. It selected LoG-sigma-1-0-mm-3D_firstorder_InterquartileRange and logarithm_ngtdm_Busyness as the predictively most robust and non-redundant features. The radiomic score based on these two features produced an AUC = 0.81. Adding the non-radiomic karnofsky performance status (KPS) to the score has increased the AUC to 0.88. Low values of the radiomic score defined a homogeneous subgroup of 50 patients with consistent absence (0%) of tumor progression. CONCLUSION: This is the first report of a strong association between MRI radiomic features and volumetric meningioma response to radiosurgery. The clinical importance of the early and reliable prediction of meningioma responsiveness to radiosurgery is based on its potential to aid individualized therapy decision making.
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Neoplasias Meníngeas , Meningioma , Radiocirurgia , Humanos , Imageamento por Ressonância Magnética , Estudos Retrospectivos , Resultado do TratamentoRESUMO
PURPOSE: To investigate if clinically asymptomatic compression of the middle cerebellar tract by extracerebral posterior fossa tumors can produce changes in diffusion tensor imaging (DTI) parameters and if these changes return to normal after Gamma Knife radiosurgery (GKRS). MATERIAL AND METHODS: In 22 patients (12 female, mean age 53.8 years) with posterior fossa tumors (14 schwannomas and 8 meningiomas), the middle cerebellar tract was tracked using DTI data. DTI parameters, such as fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD) within these tracts were determined separately on the tumor side and on the contra-lateral side. As a surrogate parameter of tract compression, we used the distance between a tangential line extending between the anterior, not affected part of the pons and the cerebellum, and the furthest extension of the tumor into the lateral rim of the pons. In a subgroup of 15 patients, DTI parameters were recorded after a follow-up of more than 2 years (mean follow-up time 37.5 months) after GKRS and compared to initial findings. RESULTS: Before GKRS, all DTI parameters within the compressed tract had increased. The increase in MD correlated significantly with the degree of tract compression (c = 0.443, p < 0.05). Follow-up examinations after GKRS showed reduction in FA and AD, whereas MD and RD increased. After correction for time elapsed after treatment and tumor type, the changes of MD and AD following treatment correlated significantly with the reduction of tract compression, but not with radiation dose. CONCLUSION: Although without obvious clinical symptoms, disorders of the middle cerebellar tract, as in the case of posterior fossa tumors, persist after reduction of tumor size. Because of the significant correlation between the change of parameters and the reduction of tract compression, initial compression and consequent relief are regarded as the main factors responsible for persistent disorders of the middle cerebellar tract. Radiosurgery dose did not contribute significantly to changes in DTI parameters.
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PURPOSE: To demonstrate that lesions of the visual pathways due to suprasellar tumors are accompanied by alterations of the visual cortex and to see if these alterations are reversible after treatment of tumors by gamma knife radiosurgery. MATERIALS AND METHODS: In 36 patients with peri-optic tumors and defects of their visual fields and in an age-matched control group, magnetic resonance imaging was performed before and after treatment. T1 weighted images were evaluated by voxel-based morphometry and correlated to the degree of visual field defects. RESULTS: In patients, grey matter density and cortical thickness were reduced in all parts of the occipital cortex, reaching significance (p < 0.05) in the left superior and middle occipital gyri, with correlation to visual field defects. Follow-up scans showed further reduction in all occipital areas. CONCLUSION: As in other peripheral lesions of the optic system, damage of the optic pathways affects the visual cortex. A prospective follow-up study is needed to determine if these alterations are reversible after successful tumor treatment.
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Adaptação Fisiológica , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/radioterapia , Plasticidade Neuronal , Radiocirurgia , Córtex Visual/diagnóstico por imagem , Adolescente , Adulto , Idoso , Neoplasias Encefálicas/fisiopatologia , Criança , Feminino , Seguimentos , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Tamanho do Órgão , Estudos Retrospectivos , Resultado do Tratamento , Transtornos da Visão/diagnóstico por imagem , Transtornos da Visão/etiologia , Transtornos da Visão/fisiopatologia , Córtex Visual/fisiopatologia , Campos Visuais/fisiologia , Vias Visuais/diagnóstico por imagem , Vias Visuais/fisiopatologia , Adulto JovemRESUMO
INTRODUCTION: In Gamma Knife Radiosurgery (GKRS) of suprasellar lesions, the exact localization of the visual pathways is important to avoid radiation induced optic neuropathy (RION). Reliable identification of the optic nerve, chiasm and tracts can be challenging using routine magnetic resonance imaging, especially in patients with lesions compressing the optic structures or in patients who had prior operation of suprasellar tumors. This study investigates the application of inversion recovery sequences (Fast gray and white matter acquisition T1 inversion recovery, FGATIR) to improve identification of the optic pathway. METHODS: Inversion recovery sequences were performed on 5 healthy volunteers, varying their inversion times between 400 and 500 ms, and between 800 and 1100 ms. Inversion times were optimized to either suppress or to preserve the signal of the optic structures, while increasing or suppressing the signal of processes within the surrounding cisterns. Inversion recovery sequences were performed before radiosurgery on 10 patients with suprasellar tumors that were compressing or displacing the optic structures. Signal intensities of gray and white matter, of CSF and tumors were measured and subtraction images were calculated. RESULTS: Compared to a standard T1-weighted sequence, delineation of the visual pathways was superior on inversion recovery images, both on images with suppression of the optic structures as well on images with suppression of its surrounding tissues, and was rated best on subtraction images. CONCLUSION: For radiosurgery of suprasellar tumors, inversion recovery sequences can be of valuable benefit for accurate delineation of optic pathway and radiosurgical dose planning in order to avoid radiation-induced normal tissue effects.
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En esta investigación se evaluara la calidad microbiológica del jarabe de carao, gotas de valeriana, capsulas de hierba de san Juan y crema de caléndula, ya que son algunas de las formas fitoterapeuticas con más demanda por la población de la ciudad de León.
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Humanos , Técnicas Microbiológicas , Fitoterapia , Nicarágua , Saúde PúblicaRESUMO
El aceite de pino es una mezcla de monoterpenos, hidrocarburos terpénicos y alcoholes terpénicos cíclicos derivados de la destilación de la madera de pino con aproximadamente un 57% de alfa-pineno como su principal componente. Es un líquido incoloro o ámbar claro con olor característico a pino. Puede mezclarse con alcohol en todas proporciones. El aceite se obtiene por destilación mediante arrastre por vapor de las aguas y de las puntas enteras de las ramitas nuevas. También existen otros métodos de extracción de aceites, se puede utilizar la hidrodestilación para extraer su aceite esencial. Estos aceites son agentes utilizados por su agradable fragancia y además porque poseen acción desinfectante y bactericida. Se usa en la formulación de una gran variedad de productos domésticos de limpieza. También se emplea como humectante, aromatizante o disolvente en la industria textil. En la industria y el comercio se venden aceites de pino que muchas veces no es totalmente puro, es decir este producto está siendo adulterado. Esto puede disminuir la efectividad de sus subproductos. De aquí radica la importancia del estudio de sus propiedades las cuales son muy útiles para la industria. Obtenido una muestra de aceite extraído directamente de la madera de pino y analizando las propiedades de este se podrá saber la diferencia que radica entre el aceite de pino extraído y el aceite de pino comercial.
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Compostos Fitoquímicos , Pinus/química , Óleos de Plantas , Nicarágua , EspectrofotometriaRESUMO
La diabetes mellitus es una enfermedad metabólica crónica, severa, frecuente y progresiva. Al momento del diagnóstico, alrededor del 50 por ciento de los casos tienen complicaciones orgánicas crónicas y más de la mitad de ellos exhiben ya más de una. La retinopatía es la complicación microvascular más común de la enfermedad y la tercera en frecuencia entre todas las complicaciones consideradas en su conjunto. Es además la primera causa de ceguera adquirida en el mundo y en Chile. El objetivo de este trabajo fue realizar la pesquisa de retinopatía diabética en un grupo de 78 pacientes del club de diabéticos de Cabildo (quinta región). Para ello se les realizó un examen oftalmológico completo, que incluyó agudeza visual, tonometría, biomicroscopia y fondo de ojo directo e indirecto. La edad promedio del grupo fue de 61 años con un rango de 37 a 85 años y con predominio de sexo femenino (72 por ciento) sobre el masculino (28 por ciento). Sólo el 3,8 por ciento de los pacientes había sido anteriormente evaluado por oftalmólogo. La prevalencia de retinopatía diabética en el grupo total fue de 30 por ciento correspondiendo el 30 por ciento a formas proliferativas y el 70 por ciento a no proliferativas