979 resultados para DTI DWI ADC FA rene policistico RM diffusione
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Purpose: To evaluate the clinical potential of diffusion-weighted MR imaging with apparent diffusion coefficient (ADC) mapping for the assessment of gastrointestinal stromal tumour (GIST) response to targeted therapy in comparison with 18F-FDG PET/CT Methods and Materials: Five patients (3 W/2M, aged 56±13 y) with metastatic GIST underwent both a 18F-FDG PET/CT (Discovery LS, GE Healthcare) and a MRI (VIBE T1 Gd, DWI [b = 50,300,600] and ADC mapping) before and after change in therapy. Exams were first analysed blindly and then PET/CT images were coregistered to T1 Gd MR images for lesion detection. SUVmax and ADC were measured for the six largest lesions on MRI. The relationship between SUVmax and ADC was analysed using Spearman's correlation. Results: Altogether, 24 lesions (15 hepatic and 9 non-hepatic) were analysed on both modalities. Three PET/CT lesions (12.5%) were initially not considered on ADC and 4 lesions on the second PET/CT were excluded because of hepatic vascular activity spillover. SUVmax decreased from 7.2±7.7 g/mL to 5.9±5.9 g/mL (P = 0.53) and ADC increased from 1.2x10-3 mm2/s ± 0.4 to 1.4x10-3 mm2/s ± 0.4 (P = 0.07). There was a significant association between SUVmax decrease and ADC increase (rho= -0.64, P = 0.004). Conclusion: Changes in ADC from diffusion-weighted MRI reflect response of 18F-FDG-avid GIST to therapy. The exact diagnostic value of DWI needs to be investigated further, as well as the effect of lesion size and time under therapy before imaging. Furthermore, the proven association between SUVmax and ADC may be useful for the assessment of treatment response in 18F-FDG non-avid GIST.
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El presente trabajo muestra los datos preliminares de una estudio de cohortes prospectivo unicéntrico que pretende comparar el daño neurológico asociado a dos intervenciones cardiacas para el tratamiento de la estenosis aórtica severa. Concretamente se analiza la aparición de lesiones isquémica agudas cerebrales detectadas por RM tras los dos procedimientos y su posible asociación con alteraciones del estado neurocognitivo en la evolución. La presentación actual solo muestra los datos preliminares de los resultados de la RM cerebral. En el apartado métodos se describe también como se realizó la valoración del estado neurocognitivo, no obstante, los resultados de estas valoraciones y su posible correlación con las lesiones en la RM cerebral aún no estan analizados y por lo tanto no se presentan.
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BACKGROUND: Despite major advances in care of premature infants, survivors exhibit mild cognitive deficits in around 40%. Beside severe intraventricular haemorrhages (IVH) and cystic periventricular leucomalacia (PVL), more subtle patterns such as grade I and II IVH, punctuate WM lesions and diffuse PVL might be linked to the cognitive deficits. Grey matter disease is also recognized to contribute to long-term cognitive impairment.¦OBJECTIVE: We intend to use novel MR techniques to study more precisely the different injury patterns. In particular MP2RAGE (magnetization prepared dual rapid echo gradient) produces high-resolution quantitative T1 relaxation maps. This contrast is known to reflect tissue anomalies such as white matter injury in general and dysmyelination in particular. We also used diffusion tensor imaging, a quantitative technique known to reflect white matter maturation and disease.¦DESIGN/METHODS: All preterm infants born under 30 weeks of GA were included. Serial 3T MR-imaging using a neonatal head-coil at DOL 3, 10 and at term equivalent age (TEA), using DTI and MP2RAGE sequences was performed. MP2RAGE generates a T1 map and allows calculating the relaxation time T1. Multiple measurements were performed for each exam in 12 defined white and grey matter ROIs.¦RESULTS: 16 patients were recruited: mean GA 27 2/7 w (191,2d SD±10,8), mean BW 999g (SD±265). 39 MRIs were realized (12 early: mean 4,83d±1,75, 13 late: mean 18,77d±8,05 and 14 at TEA: 88,91d±8,96). Measures of relaxation time T1 show a gradual and significant decrease over time (for ROI PLIC mean±SD in ms: 2100.53±102,75, 2116,5±41,55 and 1726,42±51,31 and for ROI central WM: 2302,25±79,02, 2315,02±115,02 and 1992,7±96,37 for early, late and TEA MR respectively). These trends are also observed in grey matter area, especially in thalamus. Measurements of ADC values show similar monotonous decrease over time.¦CONCLUSIONS: From these preliminary results, we conclude that quantitative MR imaging in very preterm infants is feasible. On the successive MP2RAGE and DTI sequences, we observe a gradual decrease over time in the described ROIs, representing the progressive maturation of the WM micro-structure and interestingly the same evolution is observed in the grey matter. We speculate that our study will provide normative values for T1map and ADC and might be a predictive factor for favourable or less favourable outcome.
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La enfermedad de Alzheimer (EA) Presenil se inicia antes de los 65 años, y ha sido relacionada con una diferente presentación clínica a la EA senil. En neuroimagen, se ha descrito un patrón de atrofia cerebral concordante con las diferencias clínicas. Se realizaron estudios de RM cerebral de alto campo (3T) a pacientes con EA presenil, EA senil y controles, que se procesaron para valorar diferencias en el grosor cortical. Se obtuvieron diferencias estadísticamente significativas de grosor cortical en entre los tres grupos, observando patrones diferenciados que son congruentes con lo descrito en la literatura previa.
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El treball que es presenta vol respondre la pregunta de quina és l’experiència dels cuidadors i les cuidadores principals informals que tenen cura d’un familiar vell amb demència des de fa més de 4 anys. Després de plantejar les hipòtesis de partida, es defineixen els objectius generals i específics i s’expliquen l’interès, la justificació, la rellevància i l’aportació d’aquest estudi. En l’apartat corresponent a l’estat de la qüestió i la fonamentació conceptual, després de fer una revisió bibliogràfica, es descriuen els elements que formen part d’aquesta temàtica: perfils dels receptors de cures i de les cuidadores, significat de tenir cura, vida quotidiana i qualitat de vida i descripció del model conceptual de Virginia Henderson. En el capítol següent s’exposen la metodologia, el paradigma i el mètode d’investigació utilitzats en aquest treball, així com les matrius d’anàlisi del contingut i del discurs. A partir d’aquí s’exposen els resultats en funció dels objectius plantejats. En la discussió, s’analitzen i s’interpreten les dades obtingudes i es contraposen amb altres estudis, a més de fer-se una reflexió personal sobre els aprenentatges adquirits i una proposta de línies de treball futures. A continuació s’exposen unes conclusions per resumir la informació obtinguda. En la secció de referències bibliogràfiques es detallen les fonts consultades, i en els annexos hi consten els models d’entrevista i de matriu per a l’anàlisi de dades, el full de consentiment informat, així com el buidatge i l’anàlisi de les entrevistes.
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Collection : Oeuvre littéraire inédite. N° 1. Octobre 1925
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En el marc d'un projecte més ampli d'estudi sobre les biblioteques per a pacients a Catalunya i Espanya, s'han detectat importants vacil·lacions terminològiques en les fonts bibliogràfiques consultades a l'hora de designar les biblioteques per a pacients. L'objectiu és reflexionar sobre el que implica aquesta diversitat de designacions possibles i detectar si els termes emprats descriuen el servei que s'ofereix a partir de la consulta de les següents fonts: obres de consulta generals, obres de consulta especialitzades (terminologia, diccionaris i enciclopèdies, llistes d¿encapçalaments de matèria i tesaurus) i obres teòriques especialitzades en serveis bibliotecaris a pacients hospitalizats (monografies, articles, comunicacions, memòries i textos legals i normatius). Com que el problema va més enllà del català i el castellà, també s¿ha revisat bibliografia en anglès, francès i italià.
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FSP27 (CIDEC in humans) is a protein associated with lipid droplets that downregulates the fatty acid oxidation (FAO) rate when it is overexpressed. However, little is known about its physiological role in liver. Here, we show that fasting regulates liver expression of Fsp27 in a time-dependent manner. Thus, during the initial stages of fasting a maximal induction of 800-fold was achieved, while during the later phase of fasting, Fsp27 expression decreased. The early response to fasting can be explained by a canonical PKA-CREB-CRTC2 signaling pathway since: i) CIDEC expression was induced by forskolin, ii) Fsp27 promoter activity was increased by CREB, and iii) Fsp27 expression was upregulated in the liver of Sirt1 knockout animals. Interestingly, pharmacological (etomoxir) or genetic (Hmgcs2 interference) inhibition of the FAO rate increases the in vivo expression of Fsp27 during fasting. Similarly, CIDEC expression was upregulated in HepG2 cells by either etomoxir or HMGCS2 interference. Our data indicate that there is a kinetic mechanism of auto-regulation between short- and long-term fasting, by which free fatty acids delivered to the liver during early fasting are accumulated/exported by FSP27/CIDEC, while over longer periods of fasting they are degraded in the mitochondria through the carnitine palmitoyl transferase (CPT) system.
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Exercicis pràctics per adquirir agilitat en la lectura de les notes musicals.
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Over the last 10 years, diffusion-weighted imaging (DWI) has become an important tool to investigate white matter (WM) anomalies in schizophrenia. Despite technological improvement and the exponential use of this technique, discrepancies remain and little is known about optimal parameters to apply for diffusion weighting during image acquisition. Specifically, high b-value diffusion-weighted imaging known to be more sensitive to slow diffusion is not widely used, even though subtle myelin alterations as thought to happen in schizophrenia are likely to affect slow-diffusing protons. Schizophrenia patients and healthy controls were scanned with a high b-value (4000s/mm(2)) protocol. Apparent diffusion coefficient (ADC) measures turned out to be very sensitive in detecting differences between schizophrenia patients and healthy volunteers even in a relatively small sample. We speculate that this is related to the sensitivity of high b-value imaging to the slow-diffusing compartment believed to reflect mainly the intra-axonal and myelin bound water pool. We also compared these results to a low b-value imaging experiment performed on the same population in the same scanning session. Even though the acquisition protocols are not strictly comparable, we noticed important differences in sensitivities in the favor of high b-value imaging, warranting further exploration.
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Background: The role of the non-injured hemisphere in stroke recovery is poorly understood. In this pilot study, we sought to explore the presence of structural changes detectable by diffusion tensor imaging (DTI) in the contralesional hemispheres of patients who recovered well from ischemic stroke. Methods: We analyzed serial DTI data from 16 stroke patients who had moderate initial neurological deficits (NIHSS scores 3-12) and good functional outcome at 3-6 months (NIHSS score 0 or modified Rankin Score ≤1). We segmented the brain tissue in gray and white matter (GM and WM) and measured the apparent diffusion coefficient (ADC) and fractional anisotropy in the infarct, in the contralesional infarct mirror region as well as in concentrically expanding regions around them. Results: We found that GM and WM ADC significantly increased in the infarct region (p < 0.01) from acute to chronic time points, whereas in the infarct mirror region, GM and WM ADC increased (p < 0.01) and WM fractional anisotropy decreased (p < 0.05). No significant changes were detected in other regions. Conclusion: DTI-based metrics are sensitive to regional structural changes in the contralesional hemisphere during stroke recovery. Prospective studies in larger cohorts with varying levels of recovery are needed to confirm our findings.