315 research outputs found
A feasible and automatic free tool for T1 and ECV mapping
Purpose: Cardiac magnetic resonance (CMR) is a useful non-invasive tool for characterizing tissues and detecting myocardial fibrosis and edema. Estimation of extracellular volume fraction (ECV) using T1 sequences is emerging as an accurate biomarker in cardiac diseases associated with diffuse fibrosis. In
this study, automatic software for T1 and ECV map generation consisting of an executable file was developed and validated using phantom and human data.
Methods: T1 mapping was performed in phantoms and 30 subjects (22 patients and 8 healthy subjects) on a 1.5T MR scanner using the modified Look-Locker inversion-recovery (MOLLI) sequence prototype before and 15 min after contrast agent administration. T1 maps were generated using a Fast Nonlinear
Least Squares algorithm. Myocardial ECV maps were generated using both pre- and post-contrast T1 image registration and automatic extraction of blood relaxation rates.
Results: Using our software, pre- and post-contrast T1 maps were obtained in phantoms and healthy subjects resulting in a robust and reliable quantification as compared to reference software. Coregistration of pre- and post-contrast images improved the quality of ECV maps. Mean ECV value in healthy subjects was
24.5% ± 2.5%.
Conclusions: This study demonstrated that it is possible to obtain accurate T1 maps and informative ECV maps using our software. Pixel-wise ECV maps obtained with this automatic software made it possible to visualize and evaluate the extent and severity of ECV alterations
Cervical spondylotic myelopathy: what the neurologist should know
Cervical spondylotic myelopathy is a wellknown cause of disability among older people. A significant amount of these patients is asymptomatic. Once the symptoms start the worsening may follow a progressive manner. We should suspect of spondylotic myelopathy in any individual over 55 years presenting progressive changes in gait or losing fine motor control of the upper limbs. Despite its frequent prevalence, this condition is still neglected and many times confused with other supratentorial lesions regarding diagnostic. Here we address some of most important aspects of this disease, calling attention to pathophysiology, the natural history. presentation, differential diagnosis, clinical assessment and treatment.Natl Inst Traumatol & Orthoped, Rio de Janeiro, BrazilUniv Severino Sombra, Div Neurol, Grad Program Neurol Neurosci, Tavares Macedo St 95-902, BR-24220215 Vassouras, RJ, BrazilUniv Severino Sombra, Masters Program Urgencia & Emergencia Med, Vassouras, RJ, BrazilUniv Fed Estado Rio de Janeiro, Sch Med, Rio de Janeiro, RJ, BrazilNeurology Division, Universidade Federal de São Paulo - UNIFESP , São Paulo, SP. BrazilUniv Fed Fluminense, Div Neurosurg, Niteroi, RJ, BrazilNeurology Division, Universidade Federal de São Paulo - UNIFESP , São Paulo, SP. BrazilWeb of Scienc
The relationships between vitamin K and cognition: a review of current evidence
Vitamin K is a fat-soluble nutrient discovered in 1935 and its role in blood coagulation has been thoroughly explored. In recent years, studies conducted in vitro and on animals highlighted vitamin K involvement in brain cells development and survival. In particular, vitamin K seems to have an antiapoptotic and anti-inflammatory effect mediated by the activation of Growth Arrest Specific Gene 6 and Protein S. Moreover, this vitamin is involved in sphingolipids metabolism, a class of lipids that participate in the proliferation, differentiation, and survival of brain cells. An altered expression in sphingolipids profile has been related to neuroinflammation and neurodegeneration. This review stems from a growing interest in the role of vitamin K in brain functions, especially in cognition, also in view of an expected increase of prevalence of Alzheimer's disease and other forms of dementia. It collects recent researches that show interesting, even though not definitive, evidence of a direct correlation between vitamin K levels and cognitive performance. Moreover, vitamin K antagonists, used worldwide as oral anticoagulants, according to recent studies may have a negative influence on cognitive domains such as visual memory, verbal fluency and brain volume. The aim of this review is to analyze the evidence of clinical studies carried out up to date on the relationship between vitamin K intake and cognitive performances. The involvement of vitamin K antagonists (VKAs) in declining cognitive performances is also addressed separately
Water Gain: As a Common Good Becomes a Financial Opportunity
The purpose of this paper is to analyze how the water has become, indirectly, an important element also in the financial markets. Nevertheless, its particular nature, vital and instrumental for human life, gives this item a peculiarity: it is difficult to generate a price but, equally, it attracts the agents that operate in the financial markets. But, like any other commodity, the water is starting to take hold in the equity markets. There is, however, a difficulty. No one can change the water as it does for other financial instruments present in the stock markets. For this reason, the investors began to bet on companies that have as reference the water sector, considered a booming business. The present work aims to analyze the performance of the assets related to the water sector in the financial markets, comparing performance against major indexes, such as Dow Jones, Nasdaq and S&P 500. Next, we wanted to verify the existence of a causal link between the water and the SP500 index in order to confirm the hypothesis that the water has become, in financial markets, a safe haven.
Keywords: Financial markets, US DJ Water, Granger test
JEL Classifications: C32, F36, G1
Resting state functional thalamic connectivity abnormalities in patients with post-stroke sleep apnoea: a pilot case-control study
OBJECTIVE: Sleep apnoea is common
after stroke, and has adverse effects on the
clinical outcome of affected cases. Its pathophysiological
mechanisms are only partially known. Increases
in brain connectivity after stroke might influence
networks involved in arousal modulation
and breathing control. The aim of this study was to
investigate the resting state functional MRI thalamic
hyper connectivity of stroke patients affected
by sleep apnoea (SA) with respect to cases not
affected, and to healthy controls (HC).
PATIENTS AND METHODS: A series of stabilized
strokes were submitted to 3T resting state
functional MRI imaging and full polysomnography.
The ventral-posterior-lateral thalamic nucleus was
used as seed.
RESULTS: At the between groups comparison
analysis, in SA cases versus HC, the regions significantly
hyper-connected with the seed were
those encoding noxious threats (frontal eye
field, somatosensory association, secondary visual
cortices). Comparisons between SA cases
versus those without SA, revealed in the former
group significantly increased connectivity with
regions modulating the response to stimuli independently
to their potentiality of threat (prefrontal,
primary and somatosensory association, superolateral
and medial-inferior temporal, associative
and secondary occipital ones). Further
significantly functionally hyper connections were
documented with regions involved also in the modulation
of breathing during sleep (pons, midbrain,
cerebellum, posterior cingulate cortices), and in
the modulation of breathing response to chemical
variations (anterior, posterior and para-hippocampal
cingulate cortices).
CONCLUSIONS: Our preliminary data support
the presence of functional hyper connectivity in
thalamic circuits modulating sensorial stimuli, in
patients with post-stroke sleep apnoea, possibly
influencing both their arousal ability and breathing
modulation during sleep
Development of the Italian Version of the National Institutes of Health Stroke Scale It-NIHSS
Background and Purpose-The National Institutes of Health Stroke Scale (NIHSS) is a basic component of the assessment of patients with acute stroke. To foster and standardize the use of the NIHSS among Italian health professionals, we translated the scale, dubbed into Italian the training and test videotapes devised by the National Institutes of Health researchers, and conducted a series of certification courses using the translated videos. Methods-Translation, text adaptation, video dubbing, and editing of the Italian NIHSS videotapes relied on a team of bilingual stroke neurologists. Three waves of training courses were organized for mixed classes of medical and nonmedical health professionals. The certification test was based on the usual set of 5 videotaped patients. Scoring rules were those provided by the National Institutes of Neurological Disorders and Stroke. Reliability of the Italian NIHSS was assessed using kappa statistics and compared with that of the original NIHSS. Results-During 3 years, 850 nurses, 460 nonneurologist physicians, and 246 neurologists were trained. Pass rates were respectively 44%, 75%, and 87%, respectively. Overall, 80% of scale items showed moderate to excellent reliability. Independent significant predictors of test failure at multivariate logistic regression were nurse profession (OR, 5.41; 95% CI, 4.07 to 7.20), older age (OR, 1.03; 95% CI, 1.02 to 1.05), and first edition of the course (OR, 3.13; 95% CI, 2.43 to 4.05). The agreement across all items between NIHSS and the Italian NIHSS was 80% (kappa = 0.70 +/- 0.18, z < 0.001). Conclusions-The Italian translation, supervised by experienced vascular neurologists, did not influence the clinimetric characteristics of the NIHSS. Our findings support the implementation of NIHSS video training in languages other than English. (Stroke. 2009; 40: 2557-2559.
Evaluation of a Novel Method Using Computed Tomography to Predict New Onset of Atrial Fibrillation or Embolic Events after Transcatheter Aortic Valve Implantation: the Role of Hounsfield Unit Density Ratio in the Left Atrial Appendage
Backgrounds: Evaluation of left atrial appendage (LAA) with angio-computed tomography (CCTA) in order to predict new onset of atrial fibrillation (AF) or embolic events is a new upcoming topic. No previous reported studies are available in patients undergoing transcatheter aortic valve implantation (TAVI).
Methods: We analyzed pre-procedural CCTA scans of 325 patients who underwent TAVI performing a linear coefficient of attenuation analyses with Hounsfield units (HU) in LAA. HU in LAA distal and proximal was calculated, as well as the ratio. A sensibility and specificity analyses was conducted in order to identify the optimal cutoff to predict new onset AF or embolic events after TAVI.
Results: Patients were divided into 4 groups according to the presence of AF. Baseline clinical and echocardiographic features were similar except for a significantly higher STS score and mitral regurgitation severity in PRE-TAVI AF group (p=0.003 and p=0.002 respectively). HU analyses showed a statistical difference in measure performed in LAA distal and in the HU LAA distal/Proximal ratio, with the lowest value in patients with pre-TAVI AF (p<0.001 and p<0.001 respectively). The ROC analyses found 0.84 as the cut-off for to predict the composite endpoint of new AF or embolic events, with sensitivity of 51% and specificity of 52% (p=0.008).
Conclusion: In patients with aortic stenosis (AS), use of LAA assessment with CCTA to predict embolic events or new onset AF is no efficacy and cannot be substituted clinical indications for prevention and therapy of embolic events
fMRI in Bell's Palsy: cortical activation is associated with clinical status in the acute and recovery phases
BACKGROUND: Using functional MRI (fMRI), we explored cortical activation in patients with acute
Bell’s palsy (BP) and analyzed its correlates with clinical status in the acute phase, and with 6-monthoutcome.
METHODS: 24 right-handed patients with acute BP within 15 days of onset and 24 healthy controls
underwent fMRI during performance of unilateral active (hemi-smiling) and passive lip movement tasks
with both the paretic and the normal lip. The degree of paresis was evaluated during the acute stage and
at the 6-month follow-up using the House-Brackmann (HB) grading scale. Complete recovery was
defined as HB grade II or less at the end of the 6-month period. The difference in the HB grade (ΔHB)
between the acute stage and the 6-month follow up was used to evaluate clinical improvement.
RESULTS: There were 24 patients with unilateral acute BP. HB grades ranged from III to VI. At six
months, 11 patients (46%) had completely recovered and 12 (50%) were partially improved. Compared
with healthy subjects, BP patients had a significantly greater activation of the frontal areas and the insula
ipsilateral to the paretic side. In BP patients, there was an inverse correlation between the activation of
the ipsilateral hemisphere when moving the paretic side and the degree of paresis at baseline. An
association was also observed between activation and clinical outcome (both complete recovery and
ΔHB).
CONCLUSIONS: In patients with Bell’s palsy, fMRI may represent a useful tool to predict long-term
outcome, guide therapeutic approach, and monitor treatment response
Evaluation of semiautomated internal carotid artery stenosis quantification from 3-dimensional contrast-enhanced magnetic resonance angiograms
Rationale and Objectives: The performance of a semiautomatic technique for internal carotid artery (ICA) stenosis quantification of the internal carotid artery in contrast-enhanced magnetic resonance angiography was evaluated. Materials and Methods: The degree of stenosis of 52 ICAs was quantified by measuring the cross-sectional area along the center lumen line. This was performed both by 3 independent observers and the semiautomated method. The degree of stenosis was defined as the amount of cross-sectional lumen reduction. Results: Agreement between the method and observers was good (weighted-kappa, kappa(w) = 0.89). Reproducibility of measurements of the semiautomated technique was better (kappa(w) = 0.97) than that of the observers (kappa(w) = 0.76), and the evaluated technique was considerably less time-consuming. Conclusions: Because the user interaction is limited, this technique can be used to replace an expert observer in 3-dimensional stenosis quantification of the ICA at CE-MRA in clinical practice
Coronary computed tomography angiography in acute chest pain: a sustainable model with remote support
Purpose: To propose a sustainable model of coronary computed tomography angiography (CCTA) use in acute coronary syndrome (ACS) in emergency department (ED) using a partially based teleradiology reporting model. We also analyzed impact of the protocol on short- and long-term patient's outcome. Methods: During a 12-month period, 104 consecutive patients admitted to the ED for acute chest pain (ACP) with low-to-intermediate risk of ACS were selected and underwent CCTA. Medical reporting was based on a model combining on-site physician and a remote radiologist supported by a web client-based teleradiology system, covering a 24/7 service. CCTA findings were correlated with the incidence of major adverse cardiovascular events (MACEs) over a 5-year follow-up. Results: CCTA ruled-out CAD in 76 patients (73.1%). Moderate (7.7%) to severe (19.2%) CAD was identified in 28 patients who were directly referred to functional tests or invasive angiography. The mean discharge time was 10.8 ± 5.8 h; patients with absent to mild disease were safely and quickly discharged. Remote reporting using a teleradiology platform was performed in 82/104 cases (78.9%), with slight impact on patient's discharge time (10.4 ± 5.6 vs. 12.1 ± 6.1 h, p: 0.24). MACEs at 6-month and at 5-year follow-up were 0.96% (n = 1/104) and 15.5% (n = 14/90). Conclusion: CCTA assessment of patients with ACP enables to quickly rule-out ACS, avoiding waste of time and resources, to identify patients with obstructive CAD which should be referred to subsequent tests and to stratify the risk of MACEs at short and long time. A partial teleradiology based 24/7 CCTA service is feasible and sustainable, even in small ED
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