Reliability of Semi-Automated Segmentations in Glioblastoma.

PURPOSE: In glioblastoma, quantitative volumetric measurements of contrast-enhancing or fluid-attenuated inversion recovery (FLAIR) hyperintense tumor compartments are needed for an objective assessment of therapy response. The aim of this study was to evaluate the reliability of a semi-automated, region-growing segmentation tool for determining tumor volume in patients with glioblastoma among different users of the software. METHODS: A total of 320 segmentations of tumor-associated FLAIR changes and contrast-enhancing tumor tissue were performed by different raters (neuroradiologists, medical students, and volunteers). All patients underwent high-resolution magnetic resonance imaging including a 3D-FLAIR and a 3D-MPRage sequence. Segmentations were done using a semi-automated, region-growing segmentation tool. Intra- and inter-rater-reliability were addressed by intra-class-correlation (ICC). Root-mean-square error (RMSE) was used to determine the precision error. Dice score was calculated to measure the overlap between segmentations. RESULTS: Semi-automated segmentation showed a high ICC (> 0.985) for all groups indicating an excellent intra- and inter-rater-reliability. Significant smaller precision errors and higher Dice scores were observed for FLAIR segmentations compared with segmentations of contrast-enhancement. Single rater segmentations showed the lowest RMSE for FLAIR of 3.3 % (MPRage: 8.2 %). Both, single raters and neuroradiologists had the lowest precision error for longitudinal evaluation of FLAIR changes. CONCLUSIONS: Semi-automated volumetry of glioblastoma was reliably performed by all groups of raters, even without neuroradiologic expertise. Interestingly, segmentations of tumor-associated FLAIR changes were more reliable than segmentations of contrast enhancement. In longitudinal evaluations, an experienced rater can detect progressive FLAIR changes of less than 15 % reliably in a quantitative way which could help to detect progressive disease earlier.

Ventilator setting in ICUs: comparing a Dutch with a European cohort.

BACKGROUND: From data collected during the third International Study on Mechanical Ventilation (ISMV), we compared data from a Dutch cohort with a European cohort. We hypothesised that tidal volumes were smaller and applied positive end-expiratory pressure (PEEP) was higher in the Netherlands, compared with the European cohort. We also compared use of non-invasive ventilation (NIV) and outcomes in both cohorts. METHODS: A post-hoc analysis of a prospective observational study of patients receiving mechanical ventilation. RESULTS: Tidal volumes were smaller (7.6 vs. 8.1 ml÷kg predicted bodyweight) in the Dutch cohort and applied PEEP was higher (8 vs. 6 cm H2O). Fewer patients admitted in the Netherlands received NIV as first mode of mechanical ventilation (7.1 vs. 16.7%). Fewer patients in the Dutch cohort developed an ICU-acquired pneumonia (4.5 vs. 12.3%, p < 0.01) and sepsis (5.7 vs. 10.9%, p = 0.03), but more patients were diagnosed as having delirium (15.8 vs. 4.6%, p < 0.01). ICU and in-hospital mortality rates were 19% and 25%, respectively, in Dutch ICUs vs. 26% and 33% in Europe (p = 0.06 and 0.03). CONCLUSION: Tidal volumes were smaller and applied PEEP was higher in the Dutch cohort compared with international data, but both Dutch and international patients received larger tidal volumes than recommended for prevention or treatment of acute respiratory distress syndrome. NIV as first mode of mechanical ventilation is less commonly used in the Netherlands. The incidence of ICU-acquired pneumonia is lower and of delirium higher in the Netherlands compared with international data.

Heart rate variability and sustained attention in ADHD children.

The major goal of the current study was to investigate the association between continuous performance tests (CPTs) and the heart rate variability (HRV) of attention deficit hyperactivity disorder (ADHD) children. The HRV, specifically the 0.10-Hz component, may be considered to be a psychophysiological index of effort allocation (motivation): The less effort the subject allocates, the greater the 0.10-Hz component. Results indicated that, compared to controls, ADHD subjects had a greater 0.10-Hz component, which was associated with poor test performance over time. Thus, using a psychophysiological measure, we were able to confirm the clinical concept of ADHD from a motivational perspective.

Downregulation of serotonin receptor subtypes by nortriptyline and adinazolam in major depressive disorder: neuroendocrine and platelet markers.

Neuroendocrine and platelet markers of serotonin (5-hydroxytryptamine, 5-HT) receptor functioning are useful tools for studying the downregulation of 5-HT receptors, a leading hypothesis for the mechanism of action of antidepressant drugs. The 5-HT releaser fenfluramine raises body temperature as well as plasma concentrations of ACTH, cortisol, and prolactin. Pretreatment with the 5-HT1 antagonist pindolol did not block the hyperthermic response to fenfluramine, mediating its actions via non-5-HT1 receptor subtypes (presumably 5-HT2/1C). We observed blunted hyperthermic responses to fenfluramine in unmedicated patients with major depressive disorder. We also observed that the neuroendocrine responses to fenfluramine were decreased by chronic treatment with the tricyclic antidepressant nortriptyline but not by chronic treatment with tricyclic antidepressant nortriptyline but not by chronic treatment with adinazolam, a triazolobenzodiazepine with purported antidepressant activity. IC50 values for ketanserin inhibition of 5-HT-induced platelet shape change response, a marker of 5-HT2/1c receptors, were elevated after nortriptyline treatment in depressed patients, and this increase could be accounted for by those subjects who responded well to antidepressant treatment. Adinazolam treatment did not alter the platelet shape change response. Our data suggest that downregulation of 5-HT2/1c receptors may be linked to the clinical response of depressed patients treated with nortriptyline.

Observations of hyperactive behaviour during vigilance.

A sustained attention deficit implies a deficit originating in the course of a task. A series of studies previously indicated that task inefficiency in hyperactive children is independent of task duration. The present study shows that differences in body activity between hyperactive and control children are also independent of task duration. However, the groups did differ in visual behaviour, i.e. hyperactive children did look away from the task more frequently as time proceeds. This visual behaviour did not interfere with task accuracy. It is argued that the results indicate that hyperactive children may have prevented a further deterioration of task efficiency over time through self stimulation.

The caffeine contents of non-alcoholic beverages.

The caffeine content of a number of non-alcoholic beverages was determined using HPLC. It was found that Diet Coke had a greater caffeine content than Coke (4.15 compared with 3.13 mg/fl oz), Tab is virtually caffeine free, and Lucozade, sold as a tonic, contains more caffeine than any of the other carbonated beverages tested (5.17 mg/fl oz). The pure instant coffee tested contained much more caffeine than the coffee/chicory mixtures (12.61 compared with 3.18 mg/fl oz). The caffeine content of Ceylon tea blends increases with the time the tea is allowed to draw (from about 8 mg/fl oz after 1 min to about 12 mg/fl oz after 20 min). Tea that has been allowed to draw for 20 min has a caffeine content similar to that of pure coffee.

Solubility changes on mixing short- and long-acting insulin preparations.

The loss of solubility of short-acting insulins when mixed in a ratio of 1:1 with intermediate-acting insulins in vitro was determined using high-performance liquid chromatography. Insulin preparations (porcine and human) from three different manufacturers were tested and various times of mixing (0-24 h) were investigated. The loss of solubility with mixtures of human insulins and with mixtures of porcine Velosulin (Nordisk) and Insulatard (Nordisk) was small at all the times used. A mixture of porcine Actrapid MC (Novo) and Monotard MC (Novo) led to a 60-95% loss of the soluble component, depending on the duration of mixing. The greater the time the greater the loss. These in vitro data indicate that short-acting insulins may lose solubility when mixed with long- or intermediate-acting ones. This phenomenon could be clinically relevant when patients are changed from mixtures of monocomponent to human insulins.

Mother-infant dialogue in the first days of life: an observational study during breast-feeding.

The temporal organization of the behaviour of children at risk can exhibit inconsistencies which may impair their adaptation. Seven mother-newborn pairs, selected for neurological and obstetric optimality of the babies, were observed during 2 breast-feedings (2nd after birth and 6th to 9th after birth). During pauses between sucking bouts the behaviours of the two partners were strongly coupled, even in the earlier feedings, which was not the case during sucking bouts themselves. Pauses which contained tactile behaviour were shorter in later feedings than in earlier ones, in contrast to both pauses without tactile behaviour and to bouts. The possible functional relevance of emerging temporal relations between partners' behaviours during breast-feeding is discussed.