Disease specific and nonspecific metabolic brain networks in behavioral variant of frontotemporal dementia.

Behavioral variant of frontotemporal dementia (bvFTD) is common among young-onset dementia patients. While bvFTD-specific multivariate metabolic brain pattern (bFDRP) has been identified previously, little is known about its temporal evolution, internal structure, effect of atrophy, and its relationship with nonspecific resting-state networks such as default mode network (DMN). In this multicenter study, we explored FDG-PET brain scans of 111 bvFTD, 26 Alzheimer's disease, 16 Creutzfeldt-Jakob's disease, 24 semantic variant primary progressive aphasia (PPA), 18 nonfluent variant PPA and 77 healthy control subjects (HC) from Slovenia, USA, and Germany. bFDRP was identified in a cohort of 20 bvFTD patients and age-matched HC using scaled subprofile model/principle component analysis and validated in three independent cohorts. It was characterized by hypometabolism in frontal cortex, insula, anterior/middle cingulate, caudate, thalamus, and temporal poles. Its expression in bvFTD patients was significantly higher compared to HC and other dementia syndromes (p < .0004), correlated with cognitive decline (p = .0001), and increased over time in longitudinal cohort (p = .0007). Analysis of internal network organization by graph-theory methods revealed prominent network disruption in bvFTD patients. We have further found a specific atrophy-related pattern grossly corresponding to bFDRP; however, its contribution to the metabolic pattern was minimal. Finally, despite the overlap between bFDRP and FDG-PET-derived DMN, we demonstrated a predominant role of the specific bFDRP. Taken together, we validated the bFDRP network as a diagnostic/prognostic biomarker specific for bvFTD, provided a unique insight into its highly reproducible internal structure, and proved that bFDRP is unaffected by structural atrophy and independent of normal resting state networks loss.

Dynamic contrast-enhanced MRI in malignant pleural mesothelioma: prediction of outcome based on DCE-MRI measurements in patients undergoing cytotoxic chemotherapy.

BACKGROUND: The malignant pleural mesothelioma (MPM) response rate to chemotherapy is low. The identification of imaging biomarkers that could help guide the most effective therapy approach for individual patients is highly desirable. Our aim was to investigate the dynamic contrast-enhanced (DCE) MR parameters as predictors for progression-free (PFS) and overall survival (OS) in patients with MPM treated with cisplatin-based chemotherapy. METHODS: Thirty-two consecutive patients with MPM were enrolled in this prospective study. Pretreatment and intratreatment DCE-MRI were scheduled in each patient. The DCE parameters were analyzed using the extended Tofts (ET) and the adiabatic approximation tissue homogeneity (AATH) model. Comparison analysis, logistic regression and ROC analysis were used to identify the predictors for the patient's outcome. RESULTS: Patients with higher pretreatment ET and AATH-calculated Ktrans and ve values had longer OS (P≤.006). Patients with a more prominent reduction in ET-calculated Ktrans and kep values during the early phase of chemotherapy had longer PFS (P =.008). No parameter was identified to predict PFS. Pre-treatment ET-calculated Ktrans was found to be an independent predictive marker for longer OS (P=.02) demonstrating the most favourable discrimination performance compared to other DCE parameters with an estimated sensitivity of 89% and specificity of 78% (AUC 0.9, 95% CI 0.74-0.98, cut off > 0.08 min-1). CONCLUSIONS: In the present study, higher pre-treatment ET-calculated Ktrans values were associated with longer OS. The results suggest that DCE-MRI might provide additional information for identifying MPM patients that may respond to chemotherapy.

Guidelines for magnetic resonance imaging in pediatric head and neck pathologies: a multicentre international consensus paper.

The use of standardized imaging protocols is paramount in order to facilitate comparable, reproducible images and, consequently, to optimize patient care. Standardized MR protocols are lacking when studying head and neck pathologies in the pediatric population. We propose an international, multicenter consensus paper focused on providing the best combination of acquisition time/technical requirements and image quality. Distinct protocols for different regions of the head and neck and, in some cases, for specific pathologies or clinical indications are recommended. This white paper is endorsed by several international scientific societies and it is the result of discussion, in consensus, among experts in pediatric head and neck imaging.

Lifelong, universal Pneumocystis jirovecii pneumonia prophylaxis: Patient uptake and adherence after kidney transplant.

INTRODUCTION: Pneumocystis jirovecii pneumonia (PJP) is a significant cause of morbidity and mortality in transplant patients yet little is known about their adherence to prophylaxis. The goal of this study was to evaluate patient uptake and long-term adherence after implementing universal, lifelong PJP prophylaxis. MATERIALS AND METHODS: This retrospective cohort study evaluated an adult kidney transplant program 18-months after initiating trimethoprim-sulfamethoxazole (TMP-SMX) 80/400 mg thrice-weekly following a cluster of PJP cases. The protocol incorporated multi-modal patient education and drug tolerability strategies to improve adherence, including a modified re-challenge strategy for TMP-SMX intolerance. Adherence was independently confirmed by the transplant pharmacist and nurse for each patient, with an a priori target ≥ 75% population on prophylaxis. RESULTS: Initial uptake was high with 237/250 (94.8%) patients starting prophylaxis. Long-term maintenance was high with 192/237 (81.0%) patients remaining on prophylaxis at 18-months. Of the remaining 45 patients who initiated prophylaxis, 36/237 (15.2%) were non-adherent and 9/237 (3.8%) discontinued prophylaxis by 18-months. Reasons for non-adherence included gastrointestinal upset, fear of drug reactions and cost; but the majority of reasons were not delineated by the patients (31/36, 86.1%). There was a statistically significant increase in serum creatinine 3.3 µmol/L (0.3-6.3 µmol/L 95% CI) and potassium 0.08 mmol/L (0.03-0.15 mmol/L 95% CI) in those prescribed TMP-SMX with only 3/237 (1.3%) patients discontinuing TMP-SMX for an increase in creatinine. CONCLUSION: High rates of patient uptake (94.8%) and long-term adherence (81.0%) were observed after implementing universal lifelong PJP prophylaxis. This may be due in part to the in-depth patient education and drug tolerability strategies employed.

Revascularization outcomes following acute ischemic stroke in patients taking direct oral anticoagulants: a single hospital cohort study.

Successful revascularization therapy is of paramount importance in patients suffering acute ischemic stroke (AIS). However, there is currently only limited evidence on revascularization outcomes for patients suffering AIS while treated with direct oral anticoagulants (DOACs). The aim of our study was to determine the efficacy and safety of intravenous thrombolysis (IVT) and mechanical reperfusion (MeR) in AIS patients taking DOACs, and compare them to randomized clinical trials (RCTs), which included patients without DOAC treatment. In an observational cohort study, we analyzed clinical and radiological outcomes following AIS for all consecutive patients on DOAC therapy treated by IVT or MeR, between 2013 and 2019, at the University Medical Center Ljubljana. Patients in the IVT group were on dabigatran treatment and have received idarucizumab as a reversal agent prior to IVT. Patients in the MeR group had a large vessel occlusion. The primary outcome of the study was efficiency, defined as significant improvement after recanalization (National Institutes of Health Stroke Scale (NIHSS) score improvement of ≥8 points after 24 h and modified Rankin Scale (mRS) ≤2 after 3 months) and safety, defined as occurrence of symptomatic intracerebral hemorrhage (SICH) and mortality. Fifty-one DOAC-treated patients with AIS were included. Nineteen dabigatran-treated patients received IVT after reversal by idarucizumab. Thirty-two patients with a large vessel occlusion (12 on dabigatran, 12 on rivaroxaban, and 8 on apixaban) received MeR. Median NIHSS at admission was 9 in the IVT group and 17 in the MeR group. A significant clinical improvement, 24 h after revascularization (median improvement of NIHSS ≥8), occurred in 84% of patients treated with IVT and 25% of patients treated with MeR. A favorable functional outcome after 3 months (modified Rankin Scale (mRS) ≤2) occurred in 84 % of patients treated with IVT and 44% of patients treated with MeR. SICH occurred in one patient (5%) in the IVT group, and in two patients (6%) in the MeR group. In summary, in our observational study of DOAC-treated AIS patients, the level of IVT efficiency was substantially better than in the RCTs. At the same time, the results of MeR treatment were on the same level as in non-DOAC AIS patients included in the RCTs. The observed safety of IVT and MeR treatment was similar to the RCTs. We propose that thrombi in patients on dabigatran may have increased susceptibility to IVT, thereby allowing for better clinical results.

Clinical and Radiological Characteristics Associated with Respiratory Failure in Unilateral Lateral Medullary Infarction.

BACKGROUND: The prognosis for unilateral lateral medullary infarction (ULMI) is generally good but may be aggravated by respiratory failure with fatal outcome. Respiratory failure has been reported in patients with severe bulbar dysfunction and large rostral medullary lesions, but its associated factors have not been systematically studied. We aimed to assess clinical and radiological characteristics associated with respiratory failure in patients with pure acute ULMI. MATERIALS AND METHODS: Seventy-one patients (median age 55 years, 59 males) with MRI-confirmed acute pure ULMI were studied retrospectively. Clinical characteristics were assessed and bulbar symptoms were scored using a scale developed for this study. MRI lesions were classified into 4 groups based on their vertical extent (localized/extensive) and the involvement of the open and/or closed medulla. Clinical characteristics, bulbar scores and MRI lesion characteristics were compared between patients with and without respiratory failure. RESULTS: Respiratory failure occurred in 8(11%) patients. All patients with respiratory failure were male (p = 0.336), had extensive lesions involving the open medulla (p = 0.061), progression of bulbar symptoms (p=0.002) and aspiration pneumonia (p < 0.001). Peak bulbar score (OR, 7.9 [95% CI, 2.3-160.0]; p < 0.001) and older age (OR, 1.2 [95%CI, 1.0-1.6]; p=0.006) were independently associated with respiratory failure. CONCLUSIONS: Extensive damage involving the open/rostral medulla, clinically presenting with severe bulbar dysfunction, in conjunction with factors such as aspiration pneumonia and older age appears to be crucial for the development of respiratory failure in pure ULMI. Further prospective studies are needed to identify other potential risk factors, pathophysiology, and effective preventive measures for respiratory failure in these patients.

A case of MV2K subtype of sporadic Creutzfeldt-Jakob disease with florid-like plaques: Similarities and differences to variant Creutzfeldt-Jakob disease.

Variant Creutzfeldt-Jakob disease (vCJD) is traditionally regarded as having a distinct clinical course, imaging study findings and neuropathological features, which in combination should allow a clear distinction from the six currently well-defined subtypes of sporadic Creutzfeldt-Jakob disease (sCJD). This is of major importance, especially from the standpoint of epidemiology. As we would like to demonstrate through this case report, the MV2K subtype of sCJD, being rare and heterogeneous in both clinical and neuropathological presentations, might challenge this concept by virtue of partial overlapping, both clinically and neuropathologically, with the characteristic phenotype of vCJD. Chiefly, we observed prolonged isolated psychiatric prodrome, new onset limb pain and late cognitive decline clinically, while florid-like plaques were present on routine histology, albeit in scarce and regionally restricted distribution when compared to vCJD. However, the issue is further complicated by the fact that a case of vCJD in a heterozygous (i.e. methionine - M and valine - V) allelic state with regard to the polymorphic codon 129 of the prion protein gene (PRNP) has recently been described in the UK, which deviated from the otherwise well-defined and constant clinicopathological phenotype that vCJD had thus far demonstrated. Taking both the facts into account, we would like to emphasize the use of complementary diagnostic methods to the established and otherwise reliable histological type-based model, particularly when confronted with a rare or atypical phenotype such as ours.

Machine learning assisted DSC-MRI radiomics as a tool for glioma classification by grade and mutation status.

BACKGROUND: Combining MRI techniques with machine learning methodology is rapidly gaining attention as a promising method for staging of brain gliomas. This study assesses the diagnostic value of such a framework applied to dynamic susceptibility contrast (DSC)-MRI in classifying treatment-naïve gliomas from a multi-center patients into WHO grades II-IV and across their isocitrate dehydrogenase (IDH) mutation status. METHODS: Three hundred thirty-three patients from 6 tertiary centres, diagnosed histologically and molecularly with primary gliomas (IDH-mutant = 151 or IDH-wildtype = 182) were retrospectively identified. Raw DSC-MRI data was post-processed for normalised leakage-corrected relative cerebral blood volume (rCBV) maps. Shape, intensity distribution (histogram) and rotational invariant Haralick texture features over the tumour mask were extracted. Differences in extracted features across glioma grades and mutation status were tested using the Wilcoxon two-sample test. A random-forest algorithm was employed (2-fold cross-validation, 250 repeats) to predict grades or mutation status using the extracted features. RESULTS: Shape, distribution and texture features showed significant differences across mutation status. WHO grade II-III differentiation was mostly driven by shape features while texture and intensity feature were more relevant for the III-IV separation. Increased number of features became significant when differentiating grades further apart from one another. Gliomas were correctly stratified by mutation status in 71% and by grade in 53% of the cases (87% of the gliomas grades predicted with distance less than 1). CONCLUSIONS: Despite large heterogeneity in the multi-center dataset, machine learning assisted DSC-MRI radiomics hold potential to address the inherent variability and presents a promising approach for non-invasive glioma molecular subtyping and grading.

The use of quetiapine in treatment of acute psychotic symptoms in an adolescent patient with primary brain calcification: a case report.

BACKGROUND: Primary brain calcification (PBC), a neurodegenerative disorder with characteristic calcium deposits in the basal ganglia and other brain areas, typically presents with various neurological and psychiatric symptoms in the fourth or fifth decade of life or later. We present the case of a patient with psychiatric manifestations much earlier than usual, in the second decade of life. CASE PRESENTATION: The case of an adolescent female with acute psychotic symptoms, emotional instability, disorganized and suicidal behavior, stereotypical movements, below average intelligence and a three-year history of headaches is reported. Among others, the presentation included tactile hallucinations with secondary hypochondriacal delusions, which are rarely described in this diagnosis. Massive calcinations in the area of the basal ganglia and thalamus were determined by computerized tomography. Other causes of brain calcification were excluded. No causative mutations were found in selected genes. All the symptoms apart from lower intellectual abilities improved with quetiapine and sertraline. The patient showed no side effects. CONCLUSIONS: This case report highlights the successful use of quetiapine for symptomatic treatment of acute psychosis due to PBC in an adolescent without exacerbating extrapyramidal symptoms.

The impact of automated hippocampal volumetry on diagnostic confidence in patients with suspected Alzheimer's disease: A European Alzheimer's Disease Consortium study.

INTRODUCTION: Hippocampal volume is a core biomarker of Alzheimer's disease (AD). However, its contribution over the standard diagnostic workup is unclear. METHODS: Three hundred fifty-six patients, under clinical evaluation for cognitive impairment, with suspected AD and Mini-Mental State Examination ≥20, were recruited across 17 European memory clinics. After the traditional diagnostic workup, diagnostic confidence of AD pathology (DCAD) was estimated by the physicians in charge. The latter were provided with the results of automated hippocampal volumetry in standardized format and DCAD was reassessed. RESULTS: An increment of one interquartile range in hippocampal volume was associated with a mean change of DCAD of -8.0% (95% credible interval: [-11.5, -5.0]). Automated hippocampal volumetry showed a statistically significant impact on DCAD beyond the contributions of neuropsychology, 18F-fluorodeoxyglucose positron emission tomography/single-photon emission computed tomography, and cerebrospinal fluid markers (-8.5, CrI: [-11.5, -5.6]; -14.1, CrI: [-19.3, -8.8]; -10.6, CrI: [-14.6, -6.1], respectively). DISCUSSION: There is a measurable effect of hippocampal volume on DCAD even when used on top of the traditional diagnostic workup.

Dynamic Susceptibility Contrast Enhanced (DSC) MRI Perfusion and Plasma Cytokine Levels in Patients after Tonic-clonic Seizures.

BACKGROUND: Inflammatory events in brain parenchyma and glial tissue are involved in epileptogenesis. Blood concentration of cytokines is shown to be elevated after tonic-clonic seizures. As a result of inflammation, blood-brain barrier leakage occurs. This can be documented by imaging techniques, such is dynamic susceptibility contrast enhanced (DSC) MRI perfusion. Our aim was to check for postictal brain inflammation by studying DSC MRI perfusion and plasma level of cytokines. We looked for correlations between number and type of introducing seizures, postictal plasma level of cytokines and parameters of DSC MRI perfusion. Furthermore, we looked for correlation of those parameters and course of the disease over one year follow up. PATIENTS AND METHODS: We prospectively enrolled 30 patients, 8-24 hours after single or repeated tonic-clonic seizures. RESULTS: 25 of them had normal perfusion parameters, while 5 had hyperperfusion. Patients with hyperperfusion were tested again, 3 months later. Two of 5 had hyperperfusion also on control measurements. Number of index seizures negatively correlated with concentration of proinflammatory cytokines IL-10, IFN-ϒ and TNF-α in a whole cohort. In patients with hyperperfusion, there were significantly lower concentrations of antiinflammatory cytokine IL-4 and higher concentrations of proinflammatory TNF-a. CONCLUSIONS: Long lasting blood- brain barrier disruption may be crucial for epileptogenesis in selected patients.

Decrease in catalytic capacity of γ-secretase can facilitate pathogenesis in sporadic and Familial Alzheimer's disease.

BACKGROUND: Alzheimer's disease can be a result of an age-induced disparity between increase in cellular metabolism of Aß peptides and decrease in maximal activity of a membrane-embedded protease γ-secretase. RESULTS: We compared activity of WT γ-secretase with the activity of 6 FAD mutants in its presenilin-1 component and 5 FAD mutants in Aß-part of its APP substrate (Familial Alzheimer's disease). All 11 FAD mutations show linear correlation between the decrease in maximal activity and the clinically observed age-of-onset and age-of-death. Biphasic-inhibitors showed that a higher ratio between physiological Aß-production and the maximal activity of γ-secretase can be observed in cells that can facilitate pathogenic changes in Aß-products. For example, Aß production in cells with WT γ-secretase is at 11% of its maximal activity, with delta-exon-9 mutant at 26%, while with M139V mutant is at 28% of the maximal activity. In the same conditions, G384A mutant is fully saturated and at its maximal activity. Similarly, Aß production in cells with γ-secretase complex carrying Aph1AL component is 12% of its maximal activity, while in cells with Aph1B complex is 26% of its maximal activity. Similar to the cell-based studies, clinical studies of biphasic dose-response in plasma samples of 54 healthy individuals showed variable ratios between physiological Aß production and the maximal activity of γ-secretase. CONCLUSIONS: The increase in the ratio between physiological Aß production and maximal activity of γ-secretase can be an early sign of pathogenic processes in enzyme-based, cell-based, and clinical studies of sporadic and Familiar Alzheimer's disease.

Non-contrast computed tomography in the diagnosis of cerebral venous sinus thrombosis.

BACKGROUND: The aim of the study was to investigate the sensitivity and specificity of non-contrast computed tomography (NCCT) in the diagnosis of cerebral venous sinus thrombosis (CVST). Methods. Screening our neurological department database, we identified 53 patients who were admitted to neurological emergency department with clinical signs of CVST. Two independent observers assessed the NCCT scans for the presence of CVST. CT venography and/or MR venography were used as a reference standard. Interobserver agreement between the two readers was assessed using Kappa statistic. Attenuation inside the cerebral venous sinuses was measured and compared between the patient and the control group. RESULTS: CVST was confirmed in 13 patients. Sensitivity and specificity of NCCT for overall presence of CVST were 100% and 83%, respectively, with Kappa value of 0.72 (a good agreement between observers). The attenuation values between CVST patients and control group were significantly different (73.4 ± 14.12 HU vs. 58.1 ± 7.58 HU; p = 0.000). The ROC analysis showed an area under the curve (AUC) of 0.916 (95% CI, 0.827 - 1.00) and an optimal cutoff value of 64 HU, leading to a sensitivity of 85% and specificity of 87%. CONCLUSIONS: NCCT as a first-line investigation has a high value for diagnosis of CVST in the emergency setting. The additional measurement of the sinus attenuation may improve the diagnostic value of the examination.

The presence of cerebral and/or systemic endothelial dysfunction in patients with leukoaraiosis--a case control pilot study.

BACKGROUND: In spite of high prevalence and clinical relevance of leukoaraiosis (LA), its pathophysiology is still incompletely understood. Theories of ischaemic genesis and a leaky blood-brain barrier are contradictory yet could share a common denominator-endothelial dysfunction (cerebral, systemic or both), which has not been studied thoroughly in LA. METHODS: Thirty patients with LA (58 years (SD 7)) and 30 gender- and age-matched controls without LA (55 years (SD 6)) were recruited. The vascular risk factors (VRF) were identical in both groups. Cerebral endothelial function was determined by cerebrovascular reactivity to L-arginine (CVR). Systemic endothelial function was determined by flow-mediated dilatation (FMD) of the brachial artery after hyperaemia. All participants underwent a brain MRI to search for radiological signs of LA that was classified according to the Fazekas score. Linear regression was used to explore the correlation between CVR and FMD in patients with LA. A 95 % confidence interval was used. For any statistical test used in the study, p ≤ 0.050 was regarded as statistically significant. RESULTS: We found a marked and significant decrease in both CVR (9.6 % (SD 3.2) vs. 15.8 % (SD 6.1), p < 0.001) and FMD (4.8 % (SD 3.1) vs. 7.4 % (SD 3.8), p = 0.004) in LA patients compared to controls. Both CVR (7.4 % (SD 3.1) vs. 12.2 % (SD 2.6), p = 0.001) and FMD (3.0 % (SD 2.2) vs. 6.4 % (SD 3.1), p = 0.011) were significantly decreased in LA subgroup Fazekas 3 compared to subgroup Fazekas 1. CVR and FMD significantly positively correlated (b = 0.192, 95 % CI = 0.031-0.354, p = 0.02). CONCLUSIONS: The results of our pilot study suggest that patients with LA have a significant impairment of both cerebral and systemic endothelial function that is larger than could be expected based on present VRF. Endothelial dysfunction increases in parallel with LA severity and correlates between cerebral and systemic arterial territory. Overall, our results suggest a so far unknown "intrinsic" generalised endothelial dysfunction in patients with LA that could be involved in LA pathophysiology. This interesting issue needs to be confirmed in larger samples since it could help better understand the mechanisms underlying LA.

Blood-brain barrier permeability imaging using perfusion computed tomography.

BACKGROUND: The blood-brain barrier represents the selective diffusion barrier at the level of the cerebral microvascular endothelium. Other functions of blood-brain barrier include transport, signaling and osmoregulation. Endothelial cells interact with surrounding astrocytes, pericytes and neurons. These interactions are crucial to the development, structural integrity and function of the cerebral microvascular endothelium. Dysfunctional blood-brain barrier has been associated with pathologies such as acute stroke, tumors, inflammatory and neurodegenerative diseases. CONCLUSIONS: Blood-brain barrier permeability can be evaluated in vivo by perfusion computed tomography - an efficient diagnostic method that involves the sequential acquisition of tomographic images during the intravenous administration of iodinated contrast material. The major clinical applications of perfusion computed tomography are in acute stroke and in brain tumor imaging.

Artery of Percheron infarction: review of literature with a case report.

BACKGROUND: Clinical features indicating an ischemic infarction in the territory of posterior cerebral circulation require a comprehensive radiologic examination, which is best achieved by a multi-modality imaging approach (computed tomography [CT], CT-perfusion, computed tomography angiography [CTA], magnetic resonance imaging [MRI] and diffusion weighted imaging [DWI]). The diagnosis of an acute ischemic infarction, where the damage of brain tissue may still be reversible, enables selection of appropriate treatment and contributes to a more favourable outcome. For these reasons it is essential to recognize common neurovascular variants in the territory of the posterior cerebral circulation, one of which is the artery of Percheron. CASE REPORT: A 69 year-old woman, last seen awake 10 hours earlier, presented with two typical clinical features of the artery of Percheron infarction, which were vertical gaze palsy and coma. Brain CT and CTA of neck and intracranial arteries upon arrival were interpreted as normal. A new brain CT scan performed 24 hours later revealed hypodensity in the medial parts of thalami. Other imaging modalities were not performed, due to the presumption that the window for the application of effective therapy was over. The diagnosis of an artery of Percheron infarction was therefore made retrospectively with the re-examination of the CTA of neck and intracranial arteries. CONCLUSIONS: A multi-modality imaging approach is necessary in every patient with suspicion of the posterior circulation infarction immediately after the onset of symptoms, especially in cases where primary imaging modalities are unremarkable and clinical features are severe, where follow-up examinations are indicated.

Analysis of risk factors for perifocal oedema after endovascular embolization of unruptured intracranial arterial aneurysms.

BACKGROUND: Endovascular embolization is a treatment of choice for the management of unruptured intracranial aneurysms, but sometimes is complicated with perianeurysmal oedema. The aim of our study was to establish incidence and outcomes of perianeurysmal oedema after endovascular coiling of unruptured intracranial aneurysms, and to reveal possible risk factors for development of this potentially serious complication. METHODS: In total 119 adult patients with endovascular embolization of unruptured intracranial aneurysm (performed at Department for Interventional Neuroradiology, Clinical Center, Kragujevac, Serbia) were included in our study. The embolizations were made by electrolite-detachable platinum coils: pure platinum, hydrophilic and combination of platinum and hydrophilic coils. Primary outcome variable was perianeurysmal oedema visualized by magnetic resonance imaging (MRI) 7, 30 and 90 days after the embolization. RESULTS: The perianurysmal oedema appeared in 47.6% of patients treated with hydrophilic coils, in 21.6% of patients treated with platinum coils, and in 53.8% of those treated with mixed type of the coils. The multivariate logistic regression showed that variables associated with occurrence of perianeurysmal oedema are volume of the aneurysm, hypertension, diabetes and smoking habit. Hypertension is the most important independent predictor of the perianeurysmal oedema, followed by smoking and diabetes. CONCLUSIONS: The results of our study suggest that older patients with larger unruptured intracranial aneurysms, who suffer from diabetes mellitus and hypertension, and have the smoking habit, are under much higher risk of having perianeurysmal oedema after endovascular coiling.

Pretreatment perfusion CT and CT volumetry in squamous cell carcinoma of the head and neck region.

PURPOSE: Perfusion computed tomography imaging (PCT) is a robust, reproducible, widely accessible non-invasive method. The objective of our study was to assess whether prospectively collected pretreatment PCT parameters and volumetric measurements of locoregionally advanced squamous cell carcinoma (SCCA) of the oral cavity, oropharynx and hypopharynx could predict the response to concomitant chemoradiotherapy with cisplatin Methods: Pretreatment contrast enhanced PCT was performed in 30 patients. Radiologic response criteria (RECIST) were used to evaluate tumor response. The correlation and predictive value of baseline PCT parameters and tumor volume were examined by using the Student's t-test, Pearson's correlation coefficient and receiver operating characteristic (ROC) curves. RESULTS: Baseline tumor volume, blood volume (BV) and blood flow (BF) were significantly higher in responders than in non-responders. Permeability surface (PS) did not show any significant difference between the two groups. Pretreatment tumor volume correlated with baseline BV (r=-0.4; p=0.01). Pretreatment tumor volume had 100% sensitivity and specificity (p=0.0001) and BV and BF also showed satisfactory sensitivity and specificity (100% and 65%, p=0.0002; 78% and 80.2%, p=0.01, respectively) for prediction of tumor response to concomitant chemoradiotherapy with cisplatin. CONCLUSION: Baseline BV, BF and tumor volume values were significantly different between responders and non-responders and could predict response to concomitant chemoradiotherapy with cisplatin in locoregionally advanced SCCA.

Collaborative robots can augment human cognition in regret-sensitive tasks.

Despite theoretical benefits of collaborative robots, disappointing outcomes are well documented by clinical studies, spanning rehabilitation, prostheses, and surgery. Cognitive load theory provides a possible explanation for why humans in the real world are not realizing the benefits of collaborative robots: high cognitive loads may be impeding human performance. Measuring cognitive availability using an electrocardiogram, we ask 25 participants to complete a virtual-reality task alongside an invisible agent that determines optimal performance by iteratively updating the Bellman equation. Three robots assist by providing environmental information relevant to task performance. By enabling the robots to act more autonomously-managing more of their own behavior with fewer instructions from the human-here we show that robots can augment participants' cognitive availability and decision-making. The way in which robots describe and achieve their objective can improve the human's cognitive ability to reason about the task and contribute to human-robot collaboration outcomes. Augmenting human cognition provides a path to improve the efficacy of collaborative robots. By demonstrating how robots can improve human cognition, this work paves the way for improving the cognitive capabilities of first responders, manufacturing workers, surgeons, and other future users of collaborative autonomy systems.