Development and validation of an open source quantification tool for DSC-MRI studies

Motivation. This work presents the development of an open source tool for the quantification of dynamic susceptibility-weighted contrast-enhanced (DSC) perfusion studies. The development of this tool is motivated by the lack of open source tools implemented on open platforms to allow external developers to implement their own quantification methods easily and without the need of paying for a development license.Materials and methods. This quantification tool was developed as a plugin for the ImageJ image analysis platform using the Java programming language. A modular approach was used in the implementation of the components, in such a way that the addition of new methods can be done without breaking any of the existing functionalities. For the validation process, images from seven patients with brain tumors were acquired and quantified with the presented tool and with a widely used clinical software package. The resulting perfusion parameters were then compared.Results. Perfusion parameters and the corresponding parametric images were obtained. When no gamma-fitting is used, an excellent agreement with the tool used as a gold-standard was obtained (R²>0.8 and values are within 95% CI limits in Bland–Altman plots).Conclusion. An open source tool that performs quantification of perfusion studies using magnetic resonance imaging has been developed and validated using a clinical software package. It works as an ImageJ plugin and the source code has been published with an open source license.This work was partially supported by the Human Frontier Science Program (Research Grant 2013).Publicad

A Bayesian model for brain tumor classification using clinical-based features

Proceedings of: IEEE International Conference on Image Processing (ICIP 2014). Paris, October 27-30, 2014.This paper tackles the problem of automatic brain tumor classification from Magnetic Resonance Imaging (MRI) where, traditionally, general-purpose texture and shape features extracted from the Region of Interest (tumor) have become the usual parameterization of the problem. Two main contributions are made in this context. First, a novel set of clinical-based features that intend to model intuitions and expert knowledge of physicians is suggested. Second, a system is proposed that is able to fuse multiple individual scores (based on a particular MRI sequence and a pathological indicator present in that sequence) by using a Bayesian model that produces a global system decision. This approximation provides a quite flexible solution able to handle missing data, which becomes a very likely case in a realistic scenario where the number clinical tests varies from one patient to another. Furthermore, the Bayesian model provides extra information concerning the uncertainty of the final decision. Our experimental results prove that the use of clinical-based feature leads to a significant increment of performance in terms of Area Under the Curve (AUC) when compared to a state-of-the art reference. Furthermore, the proposed Bayesian fusion model clearly outperforms other fusion schemes, especially when few diagnostic tests are available.Publicad

Longitudinal Neuroimaging Analysis in Mild-Moderate Alzheimer's Disease Patients Treated with Plasma Exchange with 5% Human Albumin

Altres ajuts: This study was funded by Grifols. [...] James T. Becker (Department of Psychiatry, Neurology and Psychology. University of Pittsburgh, Pittsburgh PA, USA) read and commented on an earlier draft of the manuscript. Jordi Bozzo PhD, CMPP (Grifols) is acknowledged for medical writing and editorial assistance in the preparation of the manuscript.Recently, modifications of Aβ levels in CSF and plasma associated with improvement in memory and language functions have been observed in patients with mild-moderate Alzheimer's disease (AD) treated with plasma exchange (PE) with albumin replacement. To detect structural and functional brain changes in PE-treated AD patients as part of a Phase II clinical trial. Patients received between 3 and 18 PE with albumin (Albutein ® 5%, Grifols) or sham-PE (controls) for 21 weeks (divided in one intensive and two maintenance periods) followed by 6-month follow-up. Brain perfusion assessed by SPECT scans using an automated software (NeuroGam ®) and brain structural changes assessed by MRI were performed at weeks 0 (baseline), 21, and 44 (with additional SPECT at weeks 9 and 33). Statistical parametric mapping (voxel-based analysis, SPM) and Z-scores calculations were applied to investigate changes to baseline. 42 patients were recruited (39 evaluable; 37 analyzed: 18 PE-treated; 19 controls). There was a trend toward decreasing hippocampi and total intracranial volume for both patient groups during the study (p < 0.05). After six months, PE-treated patients had less cerebral perfusion loss than controls in frontal, temporal, and parietal areas, and perfusion stabilization in Brodmann area BA38-R during the PE-treatment period (p < 0.05). SPM analysis showed stabilization or absence of progression of perfusion loss in PE-treated patients until week 21, not observed in controls. Mild-moderate AD patients showed decreased brain volume and impairment of brain perfusion as expected for the progression of the disease. PE-treatment with albumin replacement favored the stabilization of perfusion

DNA sequences within glioma-derived extracellular vesicles can cross the intact blood-brain barrier and be detected in peripheral blood of patients

Tumor-cell-secreted extracellular vesicles (EVs) can cross the disrupted bloodbrain barrier (BBB) into the bloodstream. However, in certain gliomas, the BBB remains intact, which might limit EVs release. To evaluate the ability of tumor-derived EVs to cross the BBB, we used an orthotopic xenotransplant mouse model of human glioma-cancer stem cells featuring an intact BBB. We demonstrated that all types of tumor cells-derived EVs−apoptotic bodies, shedding microvesicles and exosomes− cross the intact BBB and can be detected in the peripheral blood, which provides a minimally invasive method for their detection compared to liquid biopsies obtained from cerebrospinal fluid (CSF). Furthermore, these EVs can be readily distinguished from total murine EVs, since they carry human-specific DNA sequences relevant for GBM biology. In a small cohort of glioma patients, we finally demonstrated that peripheral blood EVs cargo can be successfully used to detect the presence of IDH1G395A, an essential biomarker in the current management of human gliomaWe are grateful for the financial support from the ‘Fondo de Investigaciones Sanitarias’ (FIS) (PI10/01069 and PI14/00077) and the ‘Miguel Servet Program’ (CP11/00147) from the ‘Instituto de Salud Carlos III’ (AAS), RTC-2015-3846-1 from Ministerio de Economía y Competitividad and FEDER fund

Long-Term Decrease in VLA-4 Expression and Functional Impairment of Dendritic Cells during Natalizumab Therapy in Patients with Multiple Sclerosis

Myeloid and plasmacytoid dendritic cells (mDCs, pDCs) are central to the initiation and the regulation of immune processes in multiple sclerosis (MS). Natalizumab (NTZ) is a humanized monoclonal antibody approved for the treatment of MS that acts by blocking expression of VLA-4 integrins on the surface of leukocytes. We determined the proportions of circulating DC subsets and analyzed expression of VLA-4 expression in 6 relapsing-remitting MS patients treated with NTZ for 1 year. VLA-4 expression levels on pDCs and mDCs decreased significantly during follow-up. In vitro coculture of peripheral blood mononuclear cells and pDCs, with different doses of NTZ in healthy controls (HC) and MS patients showed dose-dependent down-regulation of VLA-4 expression levels in both MS patients and HC, and reduced functional ability to stimulate antigen-specific T-lymphocyte responses. The biological impact of NTZ may in part be attributable to inhibition of transmigration of circulating DCs into the central nervous system, but also to functional impairment of interactions between T cells and DC

Enhanced impact energy absorption characteristics of sandwich composites through tufting

Sandwich structures are highly demanded where a high flexural stiffness per weight ratio is needed. The main limiting factor of these materials is the core/skin interface, which tends to delaminate. Tufting is one of the most promising technologies to reinforce this interface along the z-direction. In this article, the energy absorption of tufted sandwich structures under impact loads is evaluated. Six different types of tufted specimens were tested, including both carbon and glass fiber faces with three different tufting densities. The impact behavior of a sandwich panel is proved to be effectively improved by the tufting process.Peer reviewe

Experiencia preliminar en el tratamiento combinado de metástasis vertebrales mediante radiofrecuencia y cifoplastia en sesión única

Objectives: Describe our preliminary experience in the treatment of vertebral metastases by radiofrequency and Kyphoplasty combined in one single session. Material and methods: Four patients with histologically confirmed single spinal metastasis (breast, prostate, lung and myeloma in L1, L5, D12, D12, respectively) were treated. The indication in all cases was pain with a poor response to medical treatment. All patients had pain in the range 6-7 visual analogue scale (VAS). In two cases there was a lytic lesion of the spinal posterior wall. After obtaining informed consent, and under sedation and local anesthetic the procedure took place. The transpedicular approach took place with a 11 G bone puncture system. Two radiofrequency needles were coaxially inserted to carry out an ablation cycle through each pedicle. During the ablation cycle the tip of the ablation neddle stood between the anterior and middle third of the vertebral body, while the second needle was used as thermal sensor with its end to the height of the vertebral posterior wall. The duration of each cycle of ablation was 8 minutes reaching intratumoral temperatures of 70-80 ºC. Transpedicular Kyphoplasty was performed subsequently. Results: No complications were reported during or after the procedure and patients were discharged in the first 24 hours. There was an immediate improvement in pain after the procedure (with a VAS 1-2 intensity pain) in all patients. During follow up, analgesic medication was withdrawn in three patients, and there was no evidence of disease progression or recurrence of pain (pain intensity 1 (VAS) in a follow-up in the range of 8-14 months). Clinical and radiological follow-up after discharge could not be performed on a patient. Conclusion: The use of radio-frequency associated with Kyphoplasty in vertebral metastatic disease can contribute to the management of refractory pain to medical treatment.Objetivos: Describir nuestra experiencia preliminar en el tratamiento de metástasis vertebrales mediante radiofrecuencia y cifoplastia combinadas en sesión única. Material y métodos: Se trataron cuatro pacientes con metástasis vertebral única confirmada histológicamente (mama, próstata, pulmón y mieloma en D12, L1, L5 y D12, respectivamente). La indicación en todos los casos fue el dolor con una mala respuesta al tratamiento médico habitual. Todos los pacientes presentaban dolor en el rango 6-7 de la escala visual analógica (EVA). En dos casos existía lesión lítica del muro posterior. Tras la obtención del consentimiento informado se realizó el procedimiento bajo sedación e infiltración anestésica local. Se efectuó abordaje transpedicular bilateral con sistemas de punción ósea 11G. Se insertaron de forma coaxial dos agujas de radiofrecuencia para efectuar un ciclo de ablación por cada pedículo. Durante el ciclo de ablación la punta del dispositivo correspondiente se situó en la unión del tercio medio con el tercio anterior del cuerpo vertebral, empleando la segunda aguja como sensor térmico, con su extremo a la altura del muro posterior. La duración de cada ciclo de ablación fue de 8 minutos, alcanzando temperaturas intratumorales de 70-80 ºC. A continuación se realizó cifoplastia transpedicular. Resultados: No se registraron complicaciones intra-periprocedimiento, con alta domiciliaria en las 24 horas siguientes. En todos los pacientes hubo una mejoría inmediata del dolor tras el procedimiento (con dolor de intensidad 1-2 de la EVA). En tres pacientes se retiró progresivamente la medicación analgésica, sin evidencia en ninguno de ellos de progresión local de la enfermedad ni recurrencia-aumento del dolor en el seguimiento (dolor de intensidad 1 de la EVA en un seguimiento en el rango de 8-14 meses). En un paciente no se pudo efectuar seguimiento clínico-radiológico posterior al alta. Conclusión: El empleo de radiofrecuencia asociada a cifoplastia en la enfermedad metastásica vertebral puede contribuir al manejo del dolor refractario al tratamiento médico y al control local de la enfermedad

Is the cerebellum the optimal reference region for intensity normalization of perfusion MR studies in early Alzheimer's disease?

The cerebellum is the region most commonly used as a reference when normalizing the intensity of perfusion images acquired using magnetic resonance imaging (MRI) in Alzheimer's disease (AD) studies. In addition, the cerebellum provides unbiased estimations with nuclear medicine techniques. However, no reports confirm the cerebellum as an optimal reference region in MRI studies or evaluate the consequences of using different normalization regions. In this study, we address the effect of using the cerebellum, whole-brain white matter, and whole-brain cortical gray matter in the normalization of cerebral blood flow (CBF) parametric maps by comparing patients with stable mild cognitive impairment (MCI), patients with AD and healthy controls. According to our results, normalization by whole-brain cortical gray matter enables more sensitive detection of perfusion abnormalities in AD patients and reveals a larger number of affected regions than data normalized by the cerebellum or whole-brain white matter. Therefore, the cerebellum is not the most valid reference region in MRI studies for early stages of AD. After normalization by whole-brain cortical gray matter, we found a significant decrease in CBF in both parietal lobes and an increase in CBF in the right medial temporal lobe. We found no differences in perfusion between patients with stable MCI and healthy controls either before or after normalization