Mission thrombectomy 2020 (MT2020+) surveys of Caribbean stroke services: A call for action in our region.

Stroke is the leading cause of death and adult-onset disability in the Caribbean region. Despite the tremendous advances in acute stroke care in the past 25 years, treatment in the Caribbean lags stroke standards of care. Mission Thrombectomy 2020+ (MT2020+) is a metrics based global campaign focused on increasing access to organized stroke care and mechanical thrombectomy. We conducted two consecutive online surveys across the MT2020+ Caribbean Region assessing access to thrombolytics, mechanical thrombectomy and stroke centers. The first survey - Mechanical Thrombectomy Access-Caribbean sub-study, allowed a comparison between global services and those in the MT2020+ Caribbean region. This survey provided a snapshot of the current state of stroke centers worldwide and confirmed lower available stroke resources in the MT2020+ Caribbean Region which has one certified stroke center, and 9 mechanical thrombectomy capable centers. The second survey - MT2020+ Caribbean Region infrastructure survey - was designed to determine the availability of stroke resources that are key components of stroke care in participating hospitals. Key infrastructural components such as 24/7 computerized tomographic scanners, access to thrombolytic therapy and access to mechanical thrombectomy capable centers were scarce. There were low volumes of mechanical thrombectomy performed in the Caribbean compared to other countries around the world. Limited resources and inadequate stroke infrastructure remains a major challenge in the Caribbean. We advocate for governmental support and investment, public and private partnerships and legislation to increase access and availability to acute stroke treatments to allow for equal access to care for all Caribbean citizens.

Can Apparent Diffusion Coefficient (ADC) maps replace Diffusion Tensor Imaging (DTI) maps to predict the volumetric response of meningiomas to Gamma Knife Radiosurgery?

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.

MRI radiomics in the prediction of the volumetric response in meningiomas after gamma knife radiosurgery.

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.

Texture Analysis of Standard Magnetic Resonance Images to Predict Response to Gamma Knife Radiosurgery in Vestibular Schwannomas.

PURPOSE: To search for texture features of routine magnetic resonance imaging to predict tumor volume reduction and transient versus permanent tumor progression of vestibular schwannomas treated by Gamma Knife stereotactic radiosurgery. MATERIALS AND METHODS: Included were 23 patients with vestibular schwannomas treated in our center and followed over a period of 23.7-80.3 months (mean 42.7). Magnetic resonance imaging was performed on a 3-Tesla scanner and included T1-weighted images with and without contrast enhancement, T2-weighted, and fluid-attenuated inversion recovery images. Volumetric results were followed longitudinally over time and correlated to texture features as mean, minimum, maximum, standard deviation, skewness, and kurtosis of normalized signals taken from regions of interest covering the total tumor volume. RESULTS: In total, 14 tumors showed early progression during the first 5-18 months (2 cases permanent, 12 cases transient), whereas 9 tumors regressed immediately after SRS. Kurtosis of T2-weighted image intensity values turned out to predict progression best with a sensitivity and specificity of 71% and 78%. From all texture feature parameters, only the minimum of the normalized T2-weighted image intensity values correlated significantly to the final reduction of tumor volume per month (correlation coefficient = -0.634, P < 0.05, corrected for false discovery rate). CONCLUSIONS: Texture feature analysis helps to predict permanent versus transient enlargement and final volume reduction of schwannomas after SRS. Thus, alternative treatment strategies might be considered, mainly in large tumors, where further clinical deterioration cannot be excluded. To confirm these results, a prospective study including more cases and a longer follow-up period is necessary.

Compression of the middle cerebellar tract by posterior fossa tumors before and after Gamma Knife radiosurgery studied with diffusion tensor imaging.

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.

Adaptation of visual cortex to damage of visual pathways in suprasellar tumors before and after gamma knife radiosurgery.

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.

Pretreatment texture analysis of routine MR images and shape analysis of the diffusion tensor for prediction of volumetric response after radiosurgery for meningioma.

OBJECTIVEThe goal of this study was to identify parameters from routine T1- and T2-weighted MR sequences and diffusion tensor imaging (DTI) that best predict the volumetric changes in a meningioma after treatment with Gamma Knife radiosurgery (GKRS).METHODSIn 32 patients with meningioma, routine MRI and DTI data were measured before GKRS. A total of 78 parameters derived from first-level texture analysis of the pretreatment MR images, including calculation of the mean, SD, 2.5th and 97.5th percentiles, and kurtosis and skewness of data in histograms on a voxel-wise basis, were correlated with lesion volume change after a mean follow-up period of 3 years (range 19.5-63.3 months).RESULTSSeveral DTI-derived parameters correlated significantly with a meningioma volume change. The parameter that best predicted the results of GKRS was the 2.5th percentile value of the smallest eigenvalue (L3) of the diffusion tensor (correlation coefficient 0.739, p ≤ 0.001), whereas among the non-DTI parameters, only the SD of T2-weighted images correlated significantly with a tumor volume change (correlation coefficient 0.505, p ≤ 0.05, after correction for family-wise errors using false-detection-rate correction).CONCLUSIONSDTI-derived data had a higher correlation to shrinkage of meningioma volume after GKRS than data from T1- and T2-weighted image sequences. However, if only routine MR images are available, the SD of T2-weighted images can be used to predict control or possible progression of a meningioma after GKRS.

Inversion recovery sequences improve delineation of optic pathways in the proximity of suprasellar lesions.

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.

Prognostic value of diffusion tensor imaging parameters for Gamma Knife radiosurgery in meningiomas.

OBJECTIVE Diffusion tensor imaging (DTI) parameters are able to differentiate between meningioma subtypes. The hypothesis that there is a correlation between DTI parameters and the change in tumor size after Gamma Knife radiosurgery (GKRS) was analyzed. METHODS DTI parameters were measured using MRI before GKRS in 26 patients with meningiomas. The findings were correlated with the change in tumor size after treatment as measured at the last follow-up (range 12.5-45 months). RESULTS Only those meningiomas that showed the highest fractional anisotropy (FA), the lowest spherical index of the tensor ellipsoid (Cs), and the lowest radial diffusivity (RD) either increased or remained stable in terms of volume, whereas all other meningiomas decreased in volume. The correlation between the DTI parameters (correlation values of -0.81 for FA, 0.75 for Cs, 0.66 for RD, and 0.66 for mean diffusivity) and the rate of volume change per month was significant (p ≤ 0.001). Other factors, including original tumor size, prescription dose, and patient age, did not correlate significantly. CONCLUSIONS Meningiomas that show high FA values-as well as low Cs, low RD, and low mean diffusivity values-do not respond as well to GKRS in comparison with meningiomas with low FA values. This finding might be due to their higher content level of fibrous tissue. In particular, the meningioma with the highest FA value (0.444) considerably increased in volume (by 32.3% after 37 months), whereas the meningioma with the lowest FA value (0.151) showed the highest rate of reduction (3.3% per month) in this study.

Evaluación de la calidad microbiológica de cuatro formas fitoterapéuticas que se expenden en los diferentes centros botánicos de la ciudad de León / Evaluation of the microbiological quality of four phytotherapeutic forms that are sold in the different botanical centers of the city of León

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.

Determinación y comparación de propiedades físico-químicas de dos aceites de pino (Pinus oocarpa schiede) extraídos mediante las técnicas de soxhlet y clevenger / Determination and comparison of physical-chemical properties of two pine oils (Pinus oocarpa schiede) extracted by soxhlet and clevenger techniques

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.

Retinopatía diabética: pesquisa en el club de diabéticos del Hospital Doctor Hugo Moll Strasburger en Cabildo V Región Chile / Diabetic retinopathy: its prevalence among diabetic patients attending in Hospital Doctor Hugo Moll Strasburger from Cabildo V Región Chile

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