Posterior cerebral artery dissection on a serial magnetic resonance angiography

Posterior cerebral artery (PCA) dissection in children seldom is reported in the literature. This is the second report of acute PCA dissection with infarct occurring in a young child. A serial magnetic resonance angiography demonstrated a delayed and transient narrowing of the arterial caliber, which was consistent with a focal PCA dissection with delayed vascular recanalization. PCA dissection should be included in the causes of infarct in children and a thorough and serial neurovascular imaging should be considered if no cause of stroke is found.     

Magnetic resonance imaging in neonatal encephalopathy

Magnetic resonance imaging may provide invaluable information in the term born neonate with encephalopathy. However, both hardware and sequences may need adaptation from normal adult protocols. Sedation is often required to obtain good quality imaging, but anaesthesia is not necessary in this population. The perinatal history may predict the pattern of brain lesions, which, in turn, may be used to predict the neurodevelopmental outcome. Image interpretation is not easy and requires a full clinical history in addition to experience of both normal and abnormal neonatal brain appearances. Lesions evolve rapidly, and perinatally acquired leasions are at the most obvious 1-2 weeks from delivery. Early imaging in the first few days from presentation should always include diffusion-weighted sequences to identify early ischaemic change. Advanced techniques such as venography, angiography and perfusion-weighted imaging may be useful in certain situations, and serial imaging may help differentiate perinatal-acquired lesions from other pathologies.     

Brain magnetic resonance imaging and outcome after hypoxic ischaemic encephalopathy

Objective: To correlate pattern of injury on neonatal brain magnetic resonance imaging (MRI) with outcome in infants ≥36?+?0 weeks gestation with hypoxic ischaemic encephalopathy.

Methods: Prospective cohort study. Images were blindly reviewed. Children were assessed using a variety of standardised assessments.

Results: MRI brain was performed on 88 infants. Follow up was available in 73(83%) infants. Eight of 25(32%) children with normal imaging had below normal assessment scores. Eight infants (12%) had isolated punctate white matter lesions and five of these had abnormal assessment scores. Death and cerebral palsy were seen only in children with imaging scores ≥3 on basal ganglia/thalami (BGT) score or ≥4 on watershed score. No developmental concerns were raised in 3/7(43%) infants with isolated watershed injury. Ten of 13(77%) infants with isolated BGT injury died or developed cerebral palsy. All 23 children with posterior limb of the internal capsule (PLIC) injury displayed developmental difficulties.

Conclusions: Almost one-third of infants with a normal MRI brain may be at risk of developmental problems. Punctate foci of white matter injury are common and not always benign. PLIC involvement is usually associated with neurological sequelae including isolated cognitive deficits. Worst outcomes are associated with basal ganglia injury.     

Pentraxin 3 (PTX3) plasma levels and carotid intima media thickness progression in the general population

Background and aimPentraxin 3 (PTX3) is an essential component of the humoral arm of innate immunity and, like C-reactive protein, is independently associated with the risk of developing vascular events. Aim of this study was to investigate, in two large population-based surveys, the Bruneck Study and the PLIC Study, whether PTX3 plasma levels predict the progression of common carotid artery intima–media thickness (CCA-IMT), a surrogate marker of atherosclerosis, in the general population during 5 or 6 years of follow-up.ResultsIn the Bruneck Study, PTX3 plasma levels did not predict a faster progression of CCA-IMT either in the carotid artery or in the femoral artery. This finding was confirmed in the PLIC Study where subjects within the highest tertile of PTX3 did not show an increased progression of CCA-IMT. PTX3 plasma levels were also not associated with the fastest maximum IMT progression.In summary, in more than 2400 subjects from the general population, PTX3 plasma level is neither an independent predictor of progression of subclinical atherosclerosis in different arterial territories, including carotid and femoral arteries nor of incident cardiovascular events.ConclusionThese findings support the relevance of investigating the predictive value of PTX3 plasma levels only in specific settings, like overt CVD, heart failure or acute myocardial infarction.     

Prognostic values of gray matter to white matter ratios on early brain computed tomography in adult comatose patients after out-of-hospital cardiac arrest of cardiac etiology

Aim of the studyPrevious studies found that the gray matter to white matter ratio (GWR) on brain computed tomography (CT) could be used to predict poor outcomes in cardiac arrest survivors. However, these studies have included cardiac arrests of both cardiac and non-cardiac etiologies. We sought to evaluate if the GWR on brain CT can help to predict poor outcomes after out-of-hospital cardiac arrest (OHCA) of cardiac etiology.MethodsUsing a multicenter retrospective registry of adult cardiac arrest survivors treated with therapeutic hypothermia, we identified survivors of OHCA of cardiac etiology who underwent brain CT within 24 h after successful resuscitation. Gray and white matter attenuations were measured, and the GWRs were calculated as in previous studies. The prognostic values of the GWRs were analyzed, and a logistic regression analysis was performed to determine the contribution of the GWR in predicting poor outcomes (Cerebral Performance Category 3–5).Resultsof 283 included patients, 140 had good outcomes and 143 had poor outcomes. Although the GWRs could predict poor outcomes with statistical significance, the sensitivities were remarkably low (3.5% to 5.6%) at cutoff values with 100% specificity. No significant difference in predictive performance was found between the primary predictive model, containing independent poor outcome predictors, and the primary predictive model combined with the GWR.ConclusionIn a cohort of comatose adults after OHCA of cardiac etiology, the GWR demonstrated poor predictive performance and was not helpful in predicting poor outcomes.     

Toward understanding Machado-Joseph disease

Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is the most common inherited spinocerebellar ataxia and one of many polyglutamine neurodegenerative diseases. In MJD, a CAG repeat expansion encodes an abnormally long polyglutamine (polyQ) tract in the disease protein, ATXN3. Here we review MJD, focusing primarily on the function and dysfunction of ATXN3 and on advances toward potential therapies. ATXN3 is a deubiquitinating enzyme (DUB) whose highly specialized properties suggest that it participates in ubiquitin-dependent proteostasis. By virtue of its interactions with VCP, various ubiquitin ligases and other ubiquitin-linked proteins, ATXN3 may help regulate the stability or activity of many proteins in diverse cellular pathways implicated in proteotoxic stress response, aging, and cell differentiation. Expansion of the polyQ tract in ATXN3 is thought to promote an altered conformation in the protein, leading to changes in interactions with native partners and to the formation of insoluble aggregates. The development of a wide range of cellular and animal models of MJD has been crucial to the emerging understanding of ATXN3 dysfunction upon polyQ expansion. Despite many advances, however, the principal molecular mechanisms by which mutant ATXN3 elicits neurotoxicity remain elusive. In a chronic degenerative disease like MJD, it is conceivable that mutant ATXN3 triggers multiple, interconnected pathogenic cascades that precipitate cellular dysfunction and eventual cell death. A better understanding of these complex molecular mechanisms will be important as scientists and clinicians begin to focus on developing effective therapies for this incurable, fatal disorder.     

Magnetic resonance imaging in hypoxic-ischaemic encephalopathy

Magnetic resonance imaging of the brain is invaluable in assessing the neonate who presents with encephalopathy. Successful imaging requires adaptations to both the hardware and sequences used for adults. Knowledge of the perinatal and postnatal details are essential for the correct interpretation of the imaging findings. Perinatal lesions are at their most obvious on conventional imaging between 1 and 2 weeks from delivery. Very early imaging is useful to guide management in ventilated neonates but abnormalities may be subtle on conventional sequences. Diffusion-weighted imaging (DWI) is clinically useful for the early identification of ischaemic tissue in the neonatal brain, the pattern of which can predict outcome. DWI may underestimate the final extent of injury, particularly basal ganglia and thalamic lesions. Serial imaging with quantification of both tissue damage and structure size provides invaluable insights into the effects of perinatal injury on the developing brain.     

Diffusion MRI parameters of corpus callosum and corticospinal tract in neonates: Comparison between region-of-interest and whole tract averaged measurements

Purpose

Measures of white matter (WM) microstructure inferred from diffusion magnetic resonance imaging (dMRI) are useful for studying brain development. There is uncertainty about agreement between FA and MD values obtained from region-of-interest (ROI) versus whole tract approaches. We investigated agreement between dMRI measures using ROI and Probabilistic Neighbourhood Tractography (PNT) in genu of corpus callosum (gCC) and corticospinal tracts (CST).