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

Design and implementation of an adaptive coding and modulation system for microwave radio transmission in mobile backhaul networks

The design of an adaptive coding and modulation (ACM) system for microwave radio transmission in mobile backhaul networks must comply with a number of application related constraints. The system gain should be maximized within the block length limits imposed by the maximum admissible transmission delay. The microwave channel characteristics require that the ACM system possess a high flexibility in terms of code rates and modulation alphabet. This paper describes the industrial application of a pragmatic ACM system, starting from system design down to architectural design and implementation in FPGA and ASIC technologies. The performance of the implemented scheme is compared against traditional codes in simulations and in a real-time radio link FPGA-based prototype

Myocardial blood flow estimates from dynamic contrast-enhanced magnetic resonance imaging: three quantitative methods

Dynamic contrast-enhanced cardiovascular magnetic resonance imaging can be used to quantitatively assess the myocardial blood ow (MBF), recovering the tissue impulse response function for the transit of a gadolinium bolus through the myocardium. Several deconvolution techniques are available, using various models for the impulse response. The method of choice may in uence the results, producing differences that have not been deeply investigated yet. Three methods for quantifying myocardial perfusion have been compared: Fermi function modelling (FFM), the Tofts model (TM) and the gamma function model (GF), with the latter traditionally used in brain perfusion MRI. Thirty human subjects were studied at rest as well as under cold pressor test stress (submerging hands in ice-cold water), and a single bolus of gadolinium weighing 0.1 ± 0.05 mmol kg−1 was injected. Perfusion estimate differences between the methods were analysed by paired comparisons with Student’s t-test, linear regression analysis, and Bland–Altman plots, as well as also using the two-way ANOVA, considering the MBF values of all patients grouped according to two categories: calculation method and rest/stress conditions. Perfusion estimates obtained by various methods in both rest and stress conditions were not signi cantly different, and were in good agreement with the literature. The results obtained during the rst-pass transit time (20 s) yielded p-values in the range 0.20–0.28 for Student’s t-test, linear regression analysis slopes between 0.98–1.03, and R values between 0.92–1.01. From the Bland– Altman plots, the paired comparisons yielded a bias (and a 95% CI)—expressed as ml/min/g—for FFM versus TM, −0.01 (−0.20, 0.17) or 0.02 (−0.49, 0.52) at rest or under stress respectively, for FFM versus GF, −0.05 (−0.29, 0.20) or −0.07 (−0.55, 0.41) at rest or under stress, and for TM versus GF, −0.03 (−0.30, 0.24) or −0.09 (−0.43, 0.26) at rest or under stress. With the two-way ANOVA, the results were p = 0.20 for the method effect (not signi cant), p < 0.0001 for the rest/stress condition effect (highly signi cant, as expected), whereas no interaction resulted between the rest/ stress condition and method (p = 0.70, not signi cant). Considering a wider time-frame (60 s), the estimates for both rest and stress conditions were 25%–30% higher (p in the range 0.016–0.025) than those obtained in the 20 s time-frame. MBF estimates obtained by various methods under rest/stress conditions were not signi cantly different in the rst-pass transit time, encouraging quantitative perfusion estimates in DCE-CMRI with the used methods

Diffusion-weighted magnetic resonance imaging in patients with partial status epilepticus

Diffusion-weighted magnetic resonance imaging (DWI) is used to detect changes in the distribution of water molecules in regions affected by various pathologies. Like other conditions, ictal epileptic activity, such as status epilepticus (SE), can cause regional vasogenic/cytotoxic edema that reflects hemodynamic and metabolic changes. This study describes the electroclinical and neuroimaging findings in 10 patients with partial SE whose DWI evaluation disclosed periictal changes related to sustained epileptic activity. In this retrospective study we selected 10 patients with partial SE of different etiologies (six acute symptomatic SE; four with previous epilepsy and concomitant precipitating factors) who underwent video-EEG (electroencephalography) monitoring and a DWI study during the periictal phase. We analyzed ictal electroclinical features and DWI changes in the acute phase and during the follow-up period. DWI images revealed significant signal alterations in different brain regions depending on the location of ictal activity. DWI changes were highly concordant with the electroclinical findings in all 10 patients. As the SE resolved and the clinical conditions improved, DWI follow-up showed that the signal alterations gradually disappeared, thereby documenting their close relationship with ictal activity. This study confirms the usefulness of DWI imaging in clinical practice for a more accurate definition of the hemodynamic/metabolic changes occurring during sustained epileptic activity

Behavioral and Movement Disorders due to Long-Lasting Myoclonic Status Epilepticus Misdiagnosed as ADHD in a Patient with Juvenile Myoclonic Epilepsy

Epilepsy and attention-deficit/hyperactivity disorder (ADHD) likely share common underlying neural mechanisms, as often suggested by both the evidence of electroencephalography (EEG) abnormalities in ADHD patients without epilepsy and the coexistence of these 2 conditions. The differential diagnosis between epilepsy and ADHD may consequently be challenging. In this report, we describe a patient presenting with a clinical association of "tics" and behavioral disorders that appeared 6 months before our first observation and had previously been interpreted as ADHD. A video-EEG evaluation documented an electroclinical pattern of myoclonic status epilepticus. On the basis of the revised clinical data, the EEG findings, the good response to valproate, the long-lasting myoclonic status epilepticus, and the enduring epileptic abnormalities likely causing behavioral disturbances, the patient's symptoms were interpreted as being the expression of untreated juvenile myoclonic epilepsy. The EEG-functional magnetic resonance imaging study revealed, during clinical generalized spike-and-wave and polyspike-and-wave discharges, positive blood oxygen level-dependent (BOLD) signal changes bilaterally in the thalamus, the prefrontal cortex (Brodmann area 6, supplementary motor area) and the cerebellum, and negative BOLD signal changes in the regions of the default mode network. Such findings, which are typical of BOLD changes observed in idiopathic generalized epilepsy, may also shed light on the anatomofunctional network underlying ADHD

Drug resistant ADLTE and recurrent partial status epilepticus with dysphasic features in a family with a novel LGI1mutation: Electroclinical, genetic, and EEG/fMRI findings

Purpose: We characterized a family with autosomal dominant lateral temporal epilepsy (ADLTE) whose proband presented uncommon electroclinical findings such as drug-resistant seizures and recurrent episodes of status epilepticus with dysphasic features. Methods: The electroclinical characteristics and LGI1 genotype were defined in the family. In the proband, the ictal pattern was documented during video-EEG monitoring and epileptic activity was mapped by EEG/fMRI. Results: The affected members who were studied had drug-resistant seizures. In the proband, seizures with predominant dysphasic features often occurred as partial status epilepticus. The video-EEG-documented ictal activity and fMRI activation clearly indicated the elective involvement of the left posterior lateral temporal cortex. Sequencing of LGI1 exons revealed a heterozygous c.367G>A mutation in exon 4, resulting in a Glu123Lys substitution in the protein sequence. Conclusions: The uncommon clinical pattern (high seizure frequency, drug-resistance) highlights the variability of the ADLTE phenotype and extends our knowledge of the clinical spectrum associated with LGI1 mutations. © 2009 International League Against Epilepsy

Ictal haemodynamic changes in a patient affected by "subtle" Epilepsia Partialis Continua

We report on a 64 year-old woman presenting with Epilepsia Partialis Continua (EPC) affecting the left hand since the age of 24 without neurological deficit. Structural MRI showed a region of focal cortical dysplasia (FCD) over the right central gyrus and lesions in the mesial frontal and occipital cortex secondary to perinatal hypoxic injury. Ictal spike haemodynamic mapping using simultaneous EEG-fMRI revealed significant BOLD signal changes prominent in the region of FCD (larger cluster), occipital cortex (global statistical maximum), prefrontal cortex and cerebellum. The cluster over FCD was in good agreement with the result of EEG source analysis. Our findings provide an interesting illustration of the ability of EEG-fMRI to reveal epileptogenic networks confirming the intrinsic epileptogenic properties of dysplastic neurons. © 2011 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved

Global trait:environment relationships of plant communities

Abstract Plant functional traits directly affect ecosystem functions. At the species level, trait combinations depend on trade-offs representing different ecological strategies, but at the community level trait combinations are expected to be decoupled from these trade-offs because different strategies can facilitate co-existence within communities. A key question is to what extent community-level trait composition is globally filtered and how well it is related to global versus local environmental drivers. Here, we perform a global, plot-level analysis of trait–environment relationships, using a database with more than 1.1 million vegetation plots and 26,632 plant species with trait information. Although we found a strong filtering of 17 functional traits, similar climate and soil conditions support communities differing greatly in mean trait values. The two main community trait axes that capture half of the global trait variation (plant stature and resource acquisitiveness) reflect the trade-offs at the species level but are weakly associated with climate and soil conditions at the global scale. Similarly, within-plot trait variation does not vary systematically with macro-environment. Our results indicate that, at fine spatial grain, macro-environmental drivers are much less important for functional trait composition than has been assumed from floristic analyses restricted to co-occurrence in large grid cells. Instead, trait combinations seem to be predominantly filtered by local-scale factors such as disturbance, fine-scale soil conditions, niche partitioning and biotic interactions