A histogram-based similarity measure for quantitative magnetic resonance imaging: application in acute mild traumatic brain injury.

OBJECTIVES: The most commonly used summary metric in neuroimaging is the mean value, but this pays little attention to the shape of the data distribution and can therefore be insensitive to subtle changes that alter the data distribution. METHODS: We propose a distributional-based metric called the normalized histogram similarity measure (HSM) for characterization of quantitative images. We applied HSM to quantitative magnetic resonance imaging T1 relaxation data of 44 patients with mild traumatic brain injury and compared with data of 43 age-matched controls. RESULTS: Significant differences were found between the patients and the controls in 8 gray matter regions using the HSM whereas in only 1 gray matter region based on the mean values. CONCLUSIONS: Our results show that HSM is more sensitive than the standard mean values in detecting brain tissue changes. Future studies on brain tissue properties using quantitative magnetic resonance imaging should consider the use of HSM to properly capture any tissue changes.

Aneurysm treatment in Europe 2010: an internet survey.

BACKGROUND: Aneurysm (AN) treatment appears to differ from country to country and even from centre to centre. Therefore we decided to conduct a survey in order to better understand the "state of the art" in aneurysm treatment in Europe. The primary aim was to understand the roles of clipping and coiling in aneurysm treatment. METHODS: An interactive form was sent to major European neurosurgical centres. The responses relating to AN location, status (ruptured/unruptured) and treatment modality were divided with regard to the volume of cases and the centre's geographical location. RESULTS: Responses were received from 96 European centres. The main finding was that clipping was used significantly more often in Eastern Europe than in the rest of Europe to treat ruptured ANs of the anterior circulation. Almost all ruptured ANs across all locations are treated actively. The treatment of unruptured aneurysms of the anterior circulation is similar. The median relating to observed unruptured ANs across the Europe was 10 %. Posterior circulation ANs are treated predominantly by coiling, regardless of aneurysm status or geographical location. The average number of coilers versus surgeons per centre was 2.5:3.0 in Western, 1.9:3.6 in Southern, 1.9:4.3 in Eastern and 2.7:3.1 in Northern Europe. CONCLUSIONS: The way in which intracranial aneurysms are treated appears to correlate with the economic development of European countries. It is probably also affected by the lack of experienced coilers in Eastern Europe.

European research priorities for intracerebral haemorrhage.

Over 2 million people are affected by intracerebral haemorrhage (ICH) worldwide every year, one third of them dying within 1 month, and many survivors being left with permanent disability. Unlike most other stroke types, the incidence, morbidity and mortality of ICH have not declined over time. No standardised diagnostic workup for the detection of the various underlying causes of ICH currently exists, and the evidence for medical or surgical therapeutic interventions remains limited. A dedicated European research programme for ICH is needed to identify ways to reduce the burden of ICH-related death and disability. The European Research Network on Intracerebral Haemorrhage EURONICH is a multidisciplinary academic research collaboration that has been established to define current research priorities and to conduct large clinical studies on all aspects of ICH.

Recommendations for the management of intracranial haemorrhage - part I: spontaneous intracerebral haemorrhage. The European Stroke Initiative Writing Committee and the Writing Committee for the EUSI Executive Committee.

This article represents the recommendations for the management of spontaneous intracerebral haemorrhage of the European Stroke Initiative (EUSI). These recommendations are endorsed by the 3 European societies which are represented in the EUSI: the European Stroke Council, the European Neurological Society and the European Federation of Neurological Societies.

Cathepsin S expression: An independent prognostic factor in glioblastoma tumours--A pilot study.

Cysteine proteinases have been implicated in astrocytoma invasion. We recently demonstrated that cathepsin S (CatS) expression is up-regulated in astrocytomas and provided evidence for a potential role in astrocytoma invasion (Flannery et al., Am J Path 2003;163(1):175-82). We aimed to evaluate the significance of CatS in human astrocytoma progression and as a prognostic marker. Frozen tissue homogenates from 71 patients with astrocytomas and 3 normal brain specimens were subjected to ELISA analyses. Immunohistochemical analysis of CatS expression was performed on 126 paraffin-embedded tumour samples. Fifty-one astrocytoma cases were suitable for both frozen tissue and paraffin tissue analysis. ELISA revealed minimal expression of CatS in normal brain homogenates. CatS expression was increased in grade IV tumours whereas astrocytoma grades I-III exhibited lower values. Immunohistochemical analysis revealed a similar pattern of expression. Moreover, high-CatS immunohistochemical scores in glioblastomas were associated with significantly shorter survival (10 vs. 5 months, p = 0.014). With forced inclusion of patient age, radiation dose and Karnofsky score in the Cox multivariate model, CatS score was found to be an independent predictor of survival. CatS expression in astrocytomas is associated with tumour progression and poor outcome in glioblastomas. CatS may serve as a useful prognostic indicator and potential target for anti-invasive therapy.

Analysis of haemodynamic disturbance in the atherosclerotic carotid artery using computational fluid dynamics.

Computational fluid dynamics (CFD) provides a means for the quantitative analysis of haemodynamic disturbances in vivo, but most work has used phantoms or idealised geometry. Our purpose was to use CFD to analyse flow in carotid atherosclerosis using patient-specific geometry and flow data. Eight atherosclerotic carotid arteries and one healthy control artery were imaged with magnetic resonance angiography (MRA) and duplex ultrasound, and the data used to construct patient-specific computational models used for CFD and wall shear stress (WSS) analysis. There is a progressive change in three-dimensional (3-D) velocity profile and WSS profile with increasing severity of stenosis, characterised by increasing restriction of areas of low WSS, change in oscillation patterns, and progressive rise in WSS within stenoses and downstream jets. Areas of turbulent, retrograde flow and of low WSS are demonstrated in the lee of the stenoses. This study presents the largest CFD analysis of abnormal haemodynamics at the atheromatous carotid bifurcation using patient-specific data and provides the basis for further investigation of causal links between haemodynamic variables and atherogenesis and formation of unstable plaque. We propose that this provides a means for the prospective assessment of relative stroke risk in patients with carotid atherosclerosis.

Audit of head injury management in the Northern Region.

Head injury is a major cause of mortality and morbidity in the UK and is more prevalent among children and young adults. However, certain factors that contribute to deaths and brain damage can be audited. This article describes an audit of head injury management conducted by the Northern Regional Head Injury Group.