Susceptibility vessel sign on T2* magnetic resonance imaging and recanalization results of mechanical thrombectomy with stent retrievers: a multicentre cohort study.

BACKGROUND AND PURPOSE: The susceptibility vessel sign (SVS) on T2*-weighted magnetic resonance imaging has been reported in several studies as a negative predictor of early recanalization after intravenous thrombolysis. The meaning of SVS regarding the results of mechanical thrombectomy with stent retrievers was investigated. METHODS: Susceptibility vessel sign presence and length were studied in 153 acute ischaemic stroke patients (82 men; mean ± SD age 59 ± 17 years, baseline National Institutes of Health Stroke Scale score 17.2 ± 6.5) from three stroke centres, treated with either mechanical thrombectomy alone (n = 84) or bridging therapy (n = 69). Variables were compared between recanalizers, defined as thrombolysis in cerebral infarction (TICI) scores ≥2b, and non-recanalizers (TICI<2b). RESULTS: The SVS was present in 113 (73.8%) patients. There was no association between the presence of SVS and recanalization, obtained in 86 (56.2%) patients, in the whole population [odds ratio (OR) 1.24, 95% confidence interval (CI) 0.53-2.92, P = 0.84) and in treatment subgroups (bridging: OR = 0.91, 95% CI 0.29-2.87, P = 1.0; thrombectomy alone: OR = 1.85, 95% CI 0.48-7.16, P = 0.54). However, in SVS+ patients, recanalization decreased with SVS length (OR 0.94 for each additional mm, 95% CI 0.89-0.99; P = 0.02). CONCLUSIONS: The success of recanalization in acute stroke patients treated with stent retrievers was related to thrombus length but not to the presence of SVS.

An update on brain imaging in transient ischemic attack.

Neuroimaging is critical in the evaluation of patients with transient ischemic attack (TIA) and MRI is the recommended modality to image an ischemic lesion. The presence of a diffusion (DWI) lesion in a patient with transient neurological symptoms confirms the vascular origin of the deficit and is predictive of a high risk of stroke. Refinement of MR studies including high resolution DWI and perfusion imaging using either MRI or CT further improve the detection of ischemic lesions. Rapid etiological work-up includes non-invasive imaging of cervical and intracranial arteries to search for symptomatic stenosis/occlusion associated with an increased risk of stroke.

MR screening of candidates for thrombolysis: How to identify stroke mimics?

Stroke mimics account for up to a third of suspected strokes. The main causes are epileptic deficit, migraine aura, hypoglycemia, and functional disorders. Accurate recognition of stroke mimics is important for adequate identification of candidates for thrombolysis. This decreases the number of unnecessary treatments and invasive vascular investigations. Correctly identifying the cause of symptoms also avoids delaying proper care. Therefore, this pictorial review focuses on what the radiologist should know about the most common MRI patterns of stroke mimics in the first hours after onset of symptoms. The issues linked to the accurate diagnosis of stroke mimics in the management of candidates for thrombolysis will be discussed.

An apple a day ... chronic glossitis in a 4-year-old boy.

We report a case of chronic glossitis in a 4-year-old boy due to scurvy. The boy showed up in our department with a patchy depapillated tongue. A detailed dietary history revealed an unbalanced diet without any fruit or vegetable. The biological investigations showed a low serum ascorbic acid. The boy was treated by oral ascorbic acid during 15 days. The glossitis improved within one week and serum levels of vitamin C returned to the normal range. In industrial countries, scurvy became a rare disease in healthy children. However, since a few years, cases are reported in children and teenagers with unbalanced diet coming from economically favoured families. These extreme cases are one of the signs of a more general deterioration of dietary habits in paediatric populations in our societies. This emphasizes the importance of effective nutritional education programs aimed towards both parents and children.

Clot Burden Score and Collateral Status and Their Impact on Functional Outcome in Acute Ischemic Stroke.

BACKGROUND AND PURPOSE: Collateral status and thrombus length have been independently associated with functional outcome in patients with acute ischemic stroke. It has been suggested that thrombus length would influence functional outcome via interaction with the collateral circulation. We investigated the individual and combined effects of thrombus length assessed by the clot burden score and collateral status assessed by a FLAIR vascular hyperintensity-ASPECTS rating system on functional outcome (mRS). MATERIALS AND METHODS: Patients with anterior circulation acute ischemic stroke due to large-vessel occlusion from the ASTER and THRACE trials treated with endovascular thrombectomy were pooled. The clot burden score and FLAIR vascular hyperintensity score were determined on MR imaging obtained before endovascular thrombectomy. Favorable outcome was defined as an mRS score of 0-2 at 90 days. Association of the clot burden score and the FLAIR vascular hyperintensity score with favorable outcome (individual effect and interaction) was examined using logistic regression models. RESULTS: Of the 326 patients treated by endovascular thrombectomy with both the clot burden score and FLAIR vascular hyperintensity assessment, favorable outcome was observed in 165 (51%). The rate of favorable outcome increased with clot burden score (smaller clots) and FLAIR vascular hyperintensity (better collaterals) values. The association between clot burden score and functional outcome was significantly modified by the FLAIR vascular hyperintensity score, and this association was stronger in patients with good collaterals, with an adjusted OR = 6.15 (95% CI, 1.03-36.81). CONCLUSIONS: The association between the clot burden score and functional outcome varied for different collateral scores. The FLAIR vascular hyperintensity score might be a valuable prognostic factor, especially when contrast-based vascular imaging is not available.

Posterior reversible encephalopathy syndrome: a case of unusual diffusion-weighted MR images.

Posterior reversible encephalopathy (PRES) represents an uncommon entity related to multiple pathologies, the most common of which is hypertensive crisis. PRES is classically characterized as symmetrical parieto-occipital edema, but may affect other areas of the brain. Diffusion-weighted magnetic resonance imaging (DWI) is important for differentiating between vasogenic and cytotoxic edema. We present here the case of a 43-year-old woman, known to suffer from arterial hypertension and severe renal failure, who developed PRES with restricted apparent diffusion coefficients (ADC) in various cerebral areas, suggesting irreversible tissue damage. Nevertheless, follow-up cranial MRI revealed complete remission, indicating that restricted diffusion does not always lead to cell death in this pathology. The underlying pathophysiological mechanism is not well understood. Such reversibility of diffusion anomalies has already been reported with transient ischemia, vasospasm after subarachnoid hemorrhage and epilepsy but, to our knowledge, never before in PRES.

Do FLAIR vascular hyperintensities beyond the DWI lesion represent the ischemic penumbra?

BACKGROUND AND PURPOSE: In acute stroke with proximal artery occlusion, FLAIR vascular hyperintensities observed beyond the boundaries of the cortical lesion on DWI (newly defined "FLAIR vascular hyperintensity-DWI mismatch") may be a marker of tissue at risk of infarction. Our aim was to compare the occurrence of FLAIR vascular hyperintensity-DWI mismatch relative to that of perfusion-weighted imaging-DWI mismatch in patients with proximal MCA occlusion before IV thrombolysis. MATERIALS AND METHODS: In 141 consecutive patients with proximal MCA occlusion, 2 independent observers analyzed FLAIR images for the presence of FLAIR vascular hyperintensity-DWI mismatch before IV thrombolysis. PWI-DWI mismatch was defined as Volumehypoperfusion > 1.8 × VolumeDWI, with Volumehypoperfusion > 6 seconds on time to maximum value of the residue function maps in the 94 patients with available PWI. The presence of FLAIR vascular hyperintensity-DWI mismatch, PWI-DWI mismatch, and infarct growth on 24-hour follow-up DWI was compared. RESULTS: A FLAIR vascular hyperintensity-DWI mismatch was present in 102/141 (72%) patients, with an excellent interobserver reliability (κ = 0.91), and a PWI-DWI mismatch, in 61 of the 94 (65%) patients with available PWI. FLAIR vascular hyperintensity-DWI mismatch predicted PWI-DWI mismatch with a sensitivity of 92% (95% CI, 85%-99%) and a specificity of 64% (95% CI, 47%-80%). Patients with FLAIR vascular hyperintensity-DWI mismatch had smaller initial DWI lesion and larger infarct growth (P < .001) than patients without FLAIR vascular hyperintensity-DWI mismatch, even though their final infarcts remained smaller (P < .001). CONCLUSIONS: Albeit being moderately specific, probably due to inclusion of oligemic tissue, the FLAIR vascular hyperintensity-DWI mismatch identifies large PWI-DWI mismatch with high sensitivity.

Streptococcal cellulitis proved by skin biopsy in a coronary artery bypass graft patient.

There has been a question about the etiology and pathogenesis of recurrent cellulitis of the lower leg in patients following coronary artery bypass graft surgery. We observed a similar patient who had gram-positive cocci in chains, consistent with streptococci, within the dermis in a tissue biopsy specimen taken from the site of cellulitis. In addition, our patient had a second skin infection, namely, tinea pedis, which may be the portal of entry for streptococci. Concurrent treatment with a systemic antibiotic and a topical antifungal cream was effective in clearing both infections.

Tribological concepts involved in slipping accident analysis.

According to tribology science, the friction force produced at the sliding interface between a rubber piece and an inflexible surface presents three main components: the first is due to molecular adhesion between the two bodies, it occurs at the regions of real contact; the second is a hysteresis component resulting from the periodic excitation of the bulk of the rubber by surface roughness; the third is due to effects of product shape. The shape of the elastomer product and the conditions in which the friction occurs (lubricant, roughness of the inflexible surface, etc.) determine the appearance of each one of these components and its importance. Experimentations made by the French national research and safety Institute (INRS) revealed adhesion and hysteresis components in the lubricated friction of an elastomer over a representative sample of industrial floor surfaces. Measurements have been made by means of a portable friction tester (PFT) assessing sliding resistance of floor coverings. The sliding movement takes place between a braked test wheel and the floor covering. The effect of product shape is insignificant as the wheel is covered with smooth elastomer. The friction force produced at the sliding interface between the elastomer and the floor covering has been evaluated on smooth and rough floors, and under different lubrication conditions (flooded with water, large, medium and small quantities of mineral oil). Several test wheels, with different and sometimes used rubber coverings, have been employed. The friction force is altered when the elastomer composition or the state of the elastomer that is covering the test wheel changes. The differences pointed out depend also on floor covering roughness and lubrication. The importance of either the adhesion or hysteresis components of the friction force in accordance with the composition and the state of the elastomer that is covering the test wheel, the lubricant amount, and the floor covering roughness enable the interpretation of these differences. Some experimental results are explained from the squeeze lubricant film process. This experimental study permits a better understanding of phenomena produced at the sliding interface between a rubber sole and a floor covering when a pedestrian slips. It also plays a great part in bringing the portable friction tester into operation in order to carry out a measurement campaign of slipping resistance of industrial floors.

Assessment of slipping resistance of footwear and floor surfaces. Influence of manufacture and utilization of the products.

The slipping resistance of footwear or floor surfaces is a characteristic which it is vital to be able to quantify. Work is being carried out at the International Standard Organization (ISO) and at the European Committee for Standardization (CEN) into the slip resistance of both work shoes and protective footwear, involving analysis of the latest developments in both the validity of measuring methods and the extent of the influence of certain experimental parameters on the slip resistance. Two industrial factors, independent of the measuring process but essential to the determination of the coefficient of friction of the models have been experimentally studied, namely the effect of the manufacture of the footwear or floor surfaces on the scattering of the specific coefficient of friction of a referenced model and the effect on the coefficient of friction of mechanical wear and tear on the soles as a result of their use respectively. Work into slipping on industrial floor surfaces is less advanced. Yet, problems raised call for the same approach than for problems linked to slipping resistance of footwear, and applications will be also at first related to standardized measurement conditions.

Analysis of measurements of slip resistance of soiled surfaces on site.

The present study hinges on the use of the PFT (Portable Friction Tester) to assess the slip resistance of floors on site and aims to analyse measurements of slip resistance (602 measurements) that were carried out in 27 different firms on moistened, greasy or dirty floors. The contribution of different factors to the slipperiness of a given soiled surface can thus be identified or confirmed: quantity and viscosity of the soil, permeability and roughness of the floor, cleaning efficiency and uniformity. In particular, we observed that cleaning a soiled surface does not immediately lead to an increase in its slip resistance. The present study is exploratory in nature since so far no publication has been devoted to the analysis of measurements of slip resistance of floors in more than one firm.

Analysis of eye movements in different tasks related to the use of lift trucks.

Fork-lift trucks are frequently involved in industrial injuries that happened during driving. Insufficient visibility is one of the leading causes of occurrence of these accidents. A previous study (Hella et al, 1988) showed that +/- 75 mm is the maximal amplitude of head movements recorded to avoid the mast. However, very little is known about the areas of the forward field of view that are most frequently fixated by the eye. This article presents the results of two analyses of eye fixations during several driving situations of a lift truck that could provide a wealth of useful information for designers and for standardisation. The information it contains is also of interest in analysing visibility from all industrial vehicles.

Visibility requirements for the driver's stand of lift trucks. Experimental study of drivers' lateral head movements.

Every year, lift trucks are involved in 9000 occupational accidents with stoppage of work. Most of those accidents are due to insufficient visibility from the driver's stand of lift trucks. Draft standards related to this characteristics take into account sideways head movements of from 300 to 600 mm, depending on the proposal. Continuous recording of movements was carried out on eight subjects in a test situation involving loading, unloading and driving the vehicle loaded and unloaded. On average, during 92% of the time driving the vehicle unloaded and 87% of time driving the vehicle loaded, the head is displaced less than 150 mm. Extreme positions are the least utilised: there is a gaussian distribution of movements around the central position. Movements accepted in draft standards are therefore overestimated. These experiments offer a partial interpretation of the differences of mobility observed between each of the four tasks.

Patient "candidate" for thrombolysis: MRI is essential.

Because of its excellent sensitivity and specificity to diagnose arterial ischemic stroke (AIS) in the acute phase, MRI answers the main questions to guide treatment in "candidates" for thrombolysis. It lasts less than ten minutes, can confirm the diagnosis of AIS and distinguish it from hematomas and other "stroke mimics". It can identify the ischemic penumbra (perfusion-diffusion mismatch), determine the site of occlusion and provide prognostic information to adapt treatment in some cases in which the indications are poorly defined. In light of the most recent scientific findings, MRI can guide the treatment turning it into the investigation of choice in "candidates" for thrombolysis.

Prevalence of MRI-defined recent silent ischemia and associated bleeding risk with thrombolysis.

BACKGROUND: Uncertainties about the frequency and the associated bleeding risk of recent silent ischemia (RSI), incidentally found on pretreatment MRI, in candidates for thrombolysis require clarification because exclusion from therapy is a serious consequence for patients with such MRI findings. METHODS: We retrospectively analyzed the fluid-attenuated inversion recovery (FLAIR)/diffusion-weighted imaging (DWI) obtained before IV thrombolysis in 115 patients to search for MRI-defined RSI; these corresponded to well-developed FLAIR/DWI brain hyperintensities (RSI+), as distinct from the acute index ischemia, which typically lacked FLAIR changes. Patients without such findings were assigned to the RSI- group. Groups were compared for baseline characteristics and for rates of symptomatic and asymptomatic hemorrhagic transformation (HT) using odds ratios (OR) and their 95%confidence intervals (CI). RESULTS: We observed RSI in 21 patients (18.3%). The mean (SD) volume of RSI was 6.5 (12) mL (interquartile range 0.6-9). None of the baseline parameters differed between groups. There was no significant difference in rates of any type of HT between groups. Parenchymal hemorrhage type 1 or type 2 according to European Cooperative Acute Stroke Study criteria occurred in 2 (10%) RSI+ patients and in 10 (11%) RSI- patients (OR 0.88; 95% CI 0.18-4.37). Symptomatic HT, defined according to National Institute of Neurological Disorders and Stroke criteria, occurred in 1 (5%) RSI+ patient and in 10 (11%) RSI- patients (OR 0.42; 95% CI 0.05-3.47). CONCLUSIONS: We found that 18.3% of patients with acute stroke treated by IV thrombolysis in a stroke unit had RSI on pretreatment MRI. However, the presence of RSI was not associated with an increased risk of asymptomatic or symptomatic HT.

Use of arginine-glycine-aspartic acid adhesion peptides coupled with a new collagen scaffold to engineer a myocardium-like tissue graft.

BACKGROUND: Cardiac tissue engineering might be useful in treatment of diseased myocardium or cardiac malformations. The creation of functional, biocompatible contractile tissues, however, remains challenging. We hypothesized that coupling of arginine-glycine-aspartic acid-serine (RGD+) adhesion peptides would improve cardiomyocyte viability and differentiation and contractile performance of collagen-cell scaffolds. METHODS: Clinically approved collagen scaffolds were functionalized with RGD+ cells and seeded with cardiomyocytes. Contractile performance, cardiomyocyte viability and differentiation were analyzed at days 1 and 8 and/or after culture for 1 month. RESULTS: The method used for the RGD+ cell-collagen scaffold coupling enabled the following features: high coupling yields and complete washout of excess reagent and by-products with no need for chromatography; spectroscopic quantification of RGD+ coupling; a spacer arm of 36 A, a length reported as optimal for RGD+-peptide presentation and favorable for integrin-receptor clustering and subsequent activation. Isotonic and isometric mechanical parameters, either spontaneous or electrostimulated, exhibited good performance in RGD+ constructs. Cell number and viability was increased in RGD+ scaffolds, and we saw good organization of cell contractile apparatus with occurrence of cross-striation. CONCLUSIONS: We report a novel method of engineering a highly effective collagen-cell scaffold based on RGD+ peptides cross-linked to a clinically approved collagen matrix. The main advantages were cell contractile performance, cardiomyocyte viability and differentiation.

Sporotrichosis in a father and son.

A 41-year-old man developed classic lymphocutaneous sporotrichosis on the left arm; his 2-year-old son developed a single lesion of the "fixed" type on the right leg. Both patients responded rapidly to therapy with oral potassium iodide. Seven previous reports of familial sporotrichosis are listed, and therapy is reviewed briefly.