Longitudinal MR assessment of hypoxic ischemic injury in the immature rat brain.

Extremely preterm infants commonly show brain injury with long-term structural and functional consequences. Three-day-old (P3) rat pups share some similarities in terms of cerebral development with the very preterm infant (born at 24-28 weeks of gestation). The aim of this study was to assess longitudinally the cerebral structural and metabolic changes resulting from a moderate neonatal hypoxic ischemic injury in the P3 rat pup using high-field (9.4 T) MRI and localized (1) H magnetic resonance spectroscopy techniques. The rats were scanned longitudinally at P3, P4, P11, and P25. Volumetric measurements showed that the percentage of cortical loss in the long term correlated with size of damage 6 h after hypoxia-ischemia, male pups being more affected than female. The neurochemical profiles revealed an acute decrease of most of metabolite concentrations and an increase in lactate 24 h after hypoxia-ischemia, followed by a recovery phase leading to minor metabolic changes at P25 in spite of an abnormal brain development. Further, the increase of lactate concentration at P4 correlated with the cortical loss at P25, giving insight into the early prediction of long-term cerebral alterations following a moderate hypoxia-ischemia insult that could be of interest in clinical practice.

Aterosclerosis cérvico-cerebral subclínica: evaluación del índice REGICOR, el grosor íntima-media y el índice tobillo-brazo en la detección de sujetos en riesgo en la población

La aterosclerosis cérvico-cerebral es una de las principales causas de ictus isquémico, y por tanto, de morbimortalidad en nuestro medio. La detección de la misma en su fase asintomática mediante instrumentos como la función REGICOR, el grosor íntima-media y el índice tobillo-brazo podría mejorar las estrategias de prevención primaria. Comprobamos que, en nuestra cohorte de 933 sujetos sin antecedentes cardiovasculares, los tres factores (REGICOR≥10, GIM≥0.9, ITB≤ 0.9) se asociaron de forma independiente con la presencia de aterosclerosis cérvico-cerebral y de cualquier localización (extracraneal-intracraneal-combinada). La utilización conjunta de REGICOR e ITB podría facilitar el diagnóstico precoz de la aterosclerosis cérvico-cerebral subclínica.

Using 80 kVp versus 120 kVp in perfusion CT measurement of regional cerebral blood flow.

Perfusion CT studies of regional cerebral blood flow (rCBF), involving sequential acquisition of cerebral CT sections during IV contrast material administration, have classically been reported to be achieved at 120 kVp. We hypothesized that using 80 kVp should result in the same image quality while significantly lowering the patient's radiation dose, and we evaluated this assumption. In five patients undergoing cerebral CT survey, one section level was imaged at 120 kVp and 80 kVp, before and after IV administration of iodinated contrast material. These four cerebral CT sections obtained in each patient were analyzed with special interest to contrast, noise, and radiation dose. Contrast enhancement at 80 kVp is significantly increased (P < .001), as well as contrast between gray matter and white matter after contrast enhancement (P < .001). Mean noise at 80 kVp is not statistically different (P = .042). Finally, performance of perfusion CT studies at 80 kVp, keeping mAs constant, lowers the radiation dose by a factor of 2.8. We, thus, conclude that 80 kVp acquisition of perfusion CT studies of rCBF will result in increased contrast enhancement and should improve rCBF analysis, with a reduced patient's irradiation.

Cuidar de pessoa incapacitada por acidente vascular cerebral no domicílio: o fazer do cuidador familiar

Estudo exploratório, descritivo e quantitativo que busca identificar e descrever as atividades do familiar que cuida de pessoas incapacitadas por AVC no domicílio. A amostra constituiu-se de 35 cuidadores familiares, predominantemente mulheres, esposas ou filhas. Os cuidados realizados relacionam-se ao grau de incapacidade do familiar. As orientações recebidas denotam falta de compromisso dos profissionais com a continuidade do cuidado. O cuidador aprende a cuidar no cotidiano, com base na observação e auxílio à enfermagem na internação. As dificuldades pautam-se no esforço físico, na desinformação e no medo, no constrangimento e na vergonha em lidar com o corpo do outro. O estudo enfoca a necessidade do preparo para a alta hospitalar, salienta a família como espaço concreto para o cuidado; o aumento da expectativa de vida é uma constatação.

A case of dissection of intracranial cerebral arteries with segmental mediolytic "arteritis".

The intravital diagnosis of intracranial arterial dissection is not always possible due to atypic and non-specific clinical and radiological presentations. The postmortem pathological examination of cerebral blood vessels is therefore necessary to establish or confirm the presence of a dissecting aneurysm of intracranial arteries. Most of the described cases showed no significant underlying vascular pathology. Here we present the case of a 24-year-old women who died 5 days after admission to the hospital for a rapidly developing right-sided hemisyndrome. Neuroradiological examination had revealed ill-defined bifrontal hypodense lesions and angiographic findings were compatible with a dissection of the left extracranial internal carotid artery with embolic subocclusion of both anterior cerebral arteries. The pathological evaluation ruled out a thromboembolic occlusion of cerebral arteries and an extracranial internal carotid artery dissection but showed an extended dissecting process of variable age in the anterior circulation of the circle of Willis. The dissected vessels showed pathological changes characteristic of segmental mediolytic "arteritis" [Slavin and Gonzalez-Vitale 1976]. To our knowledge this is the first report on intracranial arteries being affected by this pathologic entity. Our case illustrates the importance of a postmortem examination of dissecting aneurysms of intracranial arteries. Careful serial section studies of dissected intracranial arteries in young subjects should be performed and may allow for a better understanding of the vascular pathology underlying the dissection processus.

Age-associated modulations of cerebral oscillatory patterns related to attention control.

Visual attention depends on bottom-up sensory activation and top-down attentional guidance. Although aging is known to affect sensory processing, its impact on the top-down control of attention remains a matter of debate. We investigated age-related modulations of brain oscillatory activity during visual attention using a variant of the attention network test (ANT) in 20 young and 28 elderly adults. We examined the EEG oscillatory responses to warning and target signals, and explored the correlates of temporal and spatial orienting as well as conflict resolution at target presentation. Time-frequency analysis was performed between 4 and 30Hz, and the relationship between behavioral and brain oscillatory responses was analyzed. Whereas temporal cueing and conflict had similar reaction time effects in both age groups, spatial cueing was more beneficial to older than younger subjects. In the absence of cue, posterior alpha activation was drastically reduced in older adults, pointing to an age-related decline in anticipatory attention. Following both cues and targets, older adults displayed pronounced motor-related activation in the low beta frequency range at the expense of attention-related posterior alpha activation prominent in younger adults. These findings support the recruitment of alternative motor-related circuits in the elderly, in line with the dedifferentiation hypothesis. Furthermore, older adults showed reduced midparietal alpha inhibition induced by temporal orienting as well as decreased posterior alpha activation associated with both spatial orienting and conflict resolution. Altogether, the results are consistent with an overall reduction of task-related alpha activity in the elderly, and provide functional evidence that younger and older adults engage distinct brain circuits at different oscillatory frequencies during attentional functions.

High-dose intravenous immunoglobulin treatment and cerebral vasospasm : a possible mechanism of ischemic encephalopathy?

A 46-year-old woman with a severe polyradiculoneuropathy treated with high-dose intravenous immunoglobulin (IVIg) presented an encephalopathy with increased blood flow velocities of the middle cerebral arteries (MCAs) detected by transcranial Doppler (TCD) studies. The similitude between this observation and another case recently reported of a patient suffering from Guillain-Barré syndrome (GBS) and cerebral blood flow abnormalities after IVIg treatment prompted us to investigate the responsibility of the IVIg therapy in the genesis of these blood flow alterations. We studied therefore by TCD 10 consecutive patients who underwent this treatment for different reasons. In 1 case we observed an asymptomatic, spontaneously reversible increase in the blood flow velocities of the MCAs consistent with a vasospasm and occurring 3-10 days after completion of the therapy. Stroke and ischemic encephalopathy have been reported as possible complications of IVIg treatment. In the case under discussion, clinical events appeared shortly after the administration of the IVIg therapy and responded favorably to a treatment with nimodipine. Other etiopathogenic mechanisms, in particular a CNS vasculopathic process related to the GBS itself, have to be considered as well. Further studies, with a larger number of patients, are therefore needed to evaluate the underlying mechanisms of blood flow abnormalities occurring sometimes in GBS patients after IVIg treatment.

A problemática do cuidador familiar do portador de acidente vascular cerebral

Objetivou-se identificar a problemática da família de pessoas acometidas de acidente vascular cerebral hospitalizadas e discutir as dificuldades do cuidador familiar para o cuidado no âmbito domiciliar. A amostra constou de 154 famílias de pacientes internados em um hospital da rede pública de saúde, Fortaleza-CE. Conforme os resultados denotam, a maioria dos cuidadores são mulheres, 104 (67,5%); 122 casos (79,2%) apresentam comprometimento familiar e alterações na vida diária em 115 dos acompanhantes (74,7%); 150 (97,4%) não receberam orientações acerca dos cuidados, mas 143 (92,9%) sentem-se seguros para acompanhá-los. O sentimento predominante foi a tristeza, 125 (81,2%), e as dúvidas principais foram: alimentação, 64 (41,6%), administração de medicamentos, 49 (29,9%), e possíveis complicações clínicas após a alta, 49 (29,9%). Estes resultados alertam para o papel do enfermeiro como educador, não somente na prevenção das doenças crônico-degenerativas, mas, também, na orientação aos cuidadores familiares sobre os cuidados dispensados após a alta hospitalar.

Mophological analysis of the human vasculature from medical imaging. Application to cerebral and coranary arteries

In this project, we have investigated new ways of modelling and analysis of human vasculature from Medical images. The research was divided in two main areas: cerebral vasculature analysis and coronary arteries modeling. Regarding cerebral vasculature analysis, we have studed cerebral aneurysms, internal carotid and the Circle of Willis (CoW). Aneurysms are abnormal vessel enlargements that can rupture causing important cerebral damages or death. The understanding of this pathology, together with its virtual treatment, and image diagnosis and prognosis, includes identification and detailed measurement of the aneurysms. In this context, we have proposed two automatic aneurysm isolation method, to separate the abnormal part of the vessel from the healthy part, to homogenize and speed-up the processing pipeline usually employed to study this pathology, [Cardenes2011TMI, arrabide2011MedPhys]. The results obtained from both methods have been also compared and validatied in [Cardenes2012MBEC]. A second important task here the analysis of the internal carotid [Bogunovic2011Media] and the automatic labelling of the CoW, Bogunovic2011MICCAI, Bogunovic2012TMI]. The second area of research covers the study of coronary arteries, specially coronary bifurcations because there is where the formation of atherosclerotic plaque is more common, and where the intervention is more challenging. Therefore, we proposed a novel modelling method from Computed Tomography Angiography (CTA) images, combined with Conventional Coronary Angiography (CCA), to obtain realistic vascular models of coronary bifurcations, presented in [Cardenes2011MICCAI], and fully validated including phantom experiments in [Cardene2013MedPhys]. The realistic models obtained from this method are being used to simulate stenting procedures, and to investigate the hemodynamic variables in coronary bifurcations in the works submitted in [Morlachi2012, Chiastra2012]. Additionally, another preliminary work has been done to reconstruct the coronary tree from rotational angiography, and published in [Cardenes2012ISBI].

Comparativecost-effectivenessanalyses of cardiacmagneticresonanceimaging versus invasive coronary angiography combined with fractional flow reserve testing to diagnose ischemia in coronary artery disease

Introduction: According to guidelines, patients with coronary artery disease (CAD) should undergo revascularization if myocardial ischemia is present. While coronary angiography (CXA) allows the morphological assessment of CAD, the fractional flow reserve (FFR) has proved to be a complementary invasive test to assess the functional significance of CAD, i.e. to detect ischemia. Perfusion Cardiac Magnetic Resonance (CMR) has turned out to be a robust non-invasive technique to assess myocardial ischemia. The objective: is to compare the cost-effectiveness ratio - defined as the costs per patient correctly diagnosed - of two algorithms used to diagnose hemodynamically significant CAD in relation to the pretest likelihood of CAD: 1) aCMRto assess ischemia before referring positive patients to CXA (CMR + CXA), 2) a CXA in all patients combined with a FFR test in patients with angiographically positive stenoses (CXA + FFR). Methods: The costs, evaluated from the health care system perspective in the Swiss, German, the United Kingdom (UK) and the United States (US) contexts, included public prices of the different tests considered as outpatient procedures, complications' costs and costs induced by diagnosis errors (false negative). The effectiveness criterion wasthe ability to accurately identify apatient with significantCAD.Test performancesused in the model were based on the clinical literature. Using a mathematical model, we compared the cost-effectiveness ratio for both algorithms for hypothetical patient cohorts with different pretest likelihood of CAD. Results: The cost-effectiveness ratio decreased hyperbolically with increasing pretest likelihood of CAD for both strategies. CMR + CXA and CXA + FFR were equally costeffective at a pretest likelihood of CAD of 62% in Switzerland, 67% in Germany, 83% in the UK and 84% in the US with costs of CHF 5'794, Euros 1'472, £ 2'685 and $ 2'126 per patient correctly diagnosed. Below these thresholds, CMR + CXA showed lower costs per patient correctly diagnosed than CXA + FFR. Implications for the health care system/professionals/patients/society These results facilitate decision making for the clinical use of new generations of imaging procedures to detect ischemia. They show to what extent the cost-effectiveness to diagnose CAD depends on the prevalence of the disease.

Selective neurodegeneration induced in rotation-mediated aggregate cell cultures by a transient switch to stationary culture conditions: a potential model to study ischemia-related pathogenic mechanisms.

Aggregating brain cell cultures at an advanced maturational stage (20-21 days in vitro) were subjected for 1-3 h to anaerobic (hypoxic) and/or stationary (ischemic) conditions. After restoration of the normal culture conditions, cell loss was estimated by measuring the release of lactate dehydrogenase as well as the irreversible decrease of cell type-specific enzyme activities, total protein and DNA content. Ischemia for 2 h induced significant neuronal cell death. Hypoxia combined with ischemia affected both neuronal and glial cells to different degrees (GABAergic neurons>cholinergic neurons>astrocytes). Hypoxic and ischemic conditions greatly stimulated the uptake of 2-deoxy-D-glucose, indicating increased glucose consumption. Furthermore, glucose restriction (5.5 mM instead of 25 mM) dramatically increased the susceptibility of neuronal and glial cells to hypoxic and ischemic conditions. Glucose media concentrations below 2 mM caused selective neuronal cell death in otherwise normal culture conditions. GABAergic neurons showed a particularly high sensitivity to glucose restriction, hypoxia, and ischemia. The pattern of ischemia-induced changes in vitro showed many similarities to in vivo findings, suggesting that aggregating brain cell cultures provide a useful in vitro model to study pathogenic mechanisms related to brain ischemia.

Mapeo cerebral en el paciente despierto en las resecciones de tumoraciones cerebrales supratentoriales. Metodología, eficacia y seguridad de la técnica.

Estudio prospectivo sobre la realización de cirugía cerebral con el paciente despierto para la exéresis de lesiones cerebrales que afectan o se encuentran cerca de áreas elocuentes (área motora, sensitiva, del lenguaje y visual). El trabajo se centra en los grados de resección que se consiguen en esta clase de cirugía, metodología a seguir, tolerancia de los pacientes, evolución de la sintomatología tras la cirugía y complicaciones intra y postoperatorios.

Estudio neurofisiológico mediante potenciales evocados auditivos de tronco cerebral y somatosensoriales en pacientes con malformación de Chiari tipo 1.

La malformación de Chiari tipo 1 (MC-1) puede condicionar fenómenos compresivos del tronco del encéfalo, de la médula espinal alta y de los nervios craneales y alterar las exploraciones neurofisiológicas de los potenciales evocados auditivos de tronco cerebral (PEATC) y de los potenciales evocados somatosensoriales (PESS). Este trabajo describe la incidencia y los tipos de hallazgos de los PEATC y PESS en una serie homogénea de 50 pacientes con MC-1 controlados en el Servicio de Neurocirugía del Hospital Universitari Vall d’Hebron y estudia su relación con la sintomatología clínica y la severidad de la malformación.