Cerebral hemodynamics on MR perfusion images before and after bypass surgery in patients with giant intracranial aneurysms

Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery. METHODS: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1). RESULTS: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values. CONCLUSION: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm.BACKGROUND AND PURPOSE: Preoperative assessment of the anatomy and dynamics of cerebral circulation for patients with giant intracranial aneurysm can improve both outcome prediction and therapeutic approach. The aim of our study was to use perfusion MR imaging to evaluate cerebral hemodynamics in such patients before and after extraintracranial high-flow bypass surgery. METHODS: Five patients with a giant aneurysm of the intracranial internal carotid artery underwent MR studies before, 1 week after, and 1 month after high-flow bypass surgery. We performed MR and digital subtraction angiography, and conventional and functional MR sequences (diffusion and perfusion). Surgery consisted of middle cerebral artery (MCA)-internal carotid artery bypass with saphenous vein grafts (n = 4) or MCA-external carotid artery bypass (n = 1). RESULTS: In four patients, MR perfusion study showed impaired hemodynamics in the vascular territory supplied by the MCA of the aneurysm side, characterized by significantly reduced mean cerebral blood flow (CBF), whereas mean transit time (MTT) and regional cerebral blood volume (rCBV) were either preserved, reduced, or increased. After surgery, angiography showed good canalization of the bypass graft. MR perfusion data obtained after surgery showed improved cerebral hemodynamics in all cases, with a return of CBF index (CBFi), MTT, and rCBV to nearly normal values. CONCLUSION: Increased MTT with increased or preserved rCBV can be interpreted as a compensatory vasodilatory response to reduced perfusion pressure, presumably from compression and disturbed flow in the giant aneurysmal sac. When maximal vasodilation has occurred, however, the brain can no longer compensate for diminished perfusion by vasodilation, and rCBV and CBFi diminish. Bypass surgery improves hemodynamics, increasing perfusion pressure and, thus, CBFi. Perfusion MR imaging can be used to evaluate cerebral hemodynamics in patients with intracranial giant aneurysm

A fiscal stimulus with deep habits and optimal monetary policy

A New-Keynesian model with deep habits and optimal monetary policy delivers a larger-than-one multiplier and consumption crowding-in. Optimized Taylor-type rules dominate a conventional Taylor rule. Consumption is crowded out if the Taylor rule is sub-optimal or if commitment is absent

Optimal Fiscal and Monetary Rules in Normal and Abnormal Times

We examine fiscal-monetary interactions in a New-Keynesian model with deep habits, distortionary taxes and a sovereign risk premium for government debt. Deep habits crucially affect the fiscal transmission mechanism in that these lead to a counter-cyclical mark-up, boosting the size of a demand-driven output expansion with important consequences for monetary and fiscal policy. We employ Bayesian estimates of the model to compute optimal monetary and fiscal policy first in `normal times' with debt starting at its steady state and then in a crisis period with a much higher initial debt-GDP ratio. Policy is conducted in terms of optimal commitment, time consistent and simple Taylor-type rules. Welfare calculations and impulse responses indicate that the ability of the simple rules to closely mimic the Ramsey optimal policy, observed in the literature with optimal monetary policy alone, is still a feature of optimal policy with fiscal instruments, but only with `passive' fiscal policy. For crisis management we find some support for slow consolidation with a more active role for tax increases rather than a decrease in government spending

Stop-event-related potentials from intracranial electrodes reveal a key role of premotor and motor cortices in stopping ongoing movements

In humans, the ability to withhold manual motor responses seems to rely on a right-lateralized frontal–basal ganglia–thalamic network, including the pre-supplementary motor area and the inferior frontal gyrus (IFG). These areas should drive subthalamic nuclei to implement movement inhibition via the hyperdirect pathway. The output of this network is expected to influence those cortical areas underlying limb movement preparation and initiation, i.e., premotor (PMA) and primary motor (M1) cortices. Electroencephalographic (EEG) studies have shown an enhancement of the N200/P300 complex in the event-related potentials (ERPs) when a planned reaching movement is successfully stopped after the presentation of an infrequent stop-signal. PMA and M1 have been suggested as possible neural sources of this ERP complex but, due to the limited spatial resolution of scalp EEG, it is not yet clear which cortical areas contribute to its generation. To elucidate the role of motor cortices, we recorded epicortical ERPs from the lateral surface of the fronto-temporal lobes of five pharmacoresistant epileptic patients performing a reaching version of the countermanding task while undergoing presurgical monitoring. We consistently found a stereotyped ERP complex on a single-trial level when a movement was successfully cancelled. These ERPs were selectively expressed in M1, PMA, and Brodmann's area (BA) 9 and their onsets preceded the end of the stop process, suggesting a causal involvement in this executive function. Such ERPs also occurred in unsuccessful-stop (US) trials, that is, when subjects moved despite the occurrence of a stop-signal, mostly when they had long reaction times (RTs). These findings support the hypothesis that motor cortices are the final target of the inhibitory command elaborated by the frontal–basal ganglia–thalamic network

Endoscopic Treatment of Pilonidal Sinus Disease: State of Art and Review of the Literature

Background: Pilonidal sinus disease (PSD) is a chronic troublesome pathology of the natal cleft of the sacrococcygeal region, with an estimated incidence of 26 cases in every 100,000 inhabitants. The aim of this review is to give a snapshot of the current literature on the endoscopic approach to PSD. Methods: A search on endoscopic treatment of pilonidal disease was performed according to PRISMA guidelines, adopting the following search terms: (pilonidal OR sacrococcygeal) and (endoscopic OR VAAPS OR EPSiT OR minimally invasive OR video-assisted OR video assisted). Results: Thirty-four articles were included in the final analysis, among which 23 were on adults and 11 were on pediatric population. The endoscopic approach is associated with painless postoperative pain, good aesthetic results, short time off work, and high patient satisfaction. Despite these advantages in short-term outcomes, results on recurrence rate in a long-term follow up are needed to definitively confirm the importance of this technique. Conclusions: The endoscopic approach is associated with significant postoperative advantages over other standard surgical approaches, and it should be included in the surgical portfolio for the treatment of PSD. According to the Italian guidelines, this technique could be considered as the gold standard for limited PSD. However, the favorable short-term-outcomes and lack of reliable data on long-term follow-up must be a stimulus to perform further high-quality studies to give definitive conclusions on this technique

Biological Prognostic Value of miR-155 for Survival Outcome in Head and Neck Squamous Cell Carcinomas: Systematic Review, Meta-Analysis and Trial Sequential Analysis

Head and neck squamous cell carcinoma (HNSCC) is one of the most common cancers worldwide; in fact, it is among the top six neoplasms, with an incidence of about 370,000 new cases per year. The 5-year survival rate, despite chemotherapy, radiotherapy, and surgery for stages 3 and 4 of the disease, is low. MicroRNAs (miRNAs) are a large group of small single-stranded non-coding endogenous RNAs, approximately 18–25 nucleotides in length, that play a significant role in the post-transcriptional regulation of genes. Recent studies investigated the tissue expression of miR-155 as a prognostic biomarker of survival in HNSCC. The purpose of this systematic review is, therefore, to investigate and summarize the current findings in the literature concerning the potential prognostic expression of tissue miR-155 in patients with HNSCC. The revision was performed according to PRISMA indications: three databases (PubMed, Scopus, and the Cochrane Register) were consulted through the use of keywords relevant to the revision topic. Totally, eight studies were included and meta-analyzed. The main results report for the aggregate HR values of 1.40 for OS, 1.36 for DFS, and 1.09 for DPS. Finally, a trial sequencing analysis was also conducted to test the robustness of the proposed meta-analysis

Sialendoscopy for salivary stones: principles, technical skills and therapeutic experience

La scialoadenite cronica ostruttiva rappresenta una delle più frequenti patologie non-neoplastiche delle ghiandole salivari e la scialoendoscopia è sempre più utilizzata nella sua diagnosi e nel suo trattamento, associata o meno con la litotripsia laser. La scialoendoscopia può essere inoltre associata ad approcci esterni mini-invasivi nelle litiasi troppo voluminose per essere rimosse con un approccio unicamente endoscopico. Il presente articolo riporta lesperienza delle Cliniche Otorinolaringoiatriche dellOspedale SantOrsola-Malpighi di Bologna e dellAzienda Ospedaliero Universitaria di Cagliari, Italia. È stata eseguita unanalisi retrospettiva su 48 pazienti (26 femmine, 22 maschi; età media di 45,3 anni; range 8-83 anni) trattati per patologia cronica ostruttiva delle ghiandole salivari maggiori mediante procedure chirurgiche endoscopiche o combinate da novembre 2010 ad aprile 2016 presso lAzienda-Ospedaliero-Universitaria di Cagliari. I risultati dellOspedale SantOrsola-Malpighi di Bologna erano stati precedentemente pubblicati. Gli aspetti tecnici della scialoendoscopia sono stati accuratamente descritti. I pazienti trattati presso lAzienda Ospedaliero Universitaria di Cagliari presentavano una patologia unilaterale in 40 casi e bilaterale in 8 casi; sono state trattate 56 ghiandole salivari maggiori (22 sottomandibolari e 34 parotidi). 5 pazienti sono stati sottoposti a scialoendoscopia bilaterale per parotite ricorrente giovanile, 10 per patologia ostruttiva non litiasica e 33 (68,75%) presentavano calcoli salivari (1 paziente presentava una litiasi parotidea bilaterale). Solo 8 pazienti sono stati sottoposti a scialectomia radicale per via esterna (5 scialectomie sottomandibolare e 3 parotidectomie). La chirurgia conservativa nei pazienti con scialoadenite cronica ostruttiva appare efficace e può essere realizzata mediante un approccio puramente endoscopico o combinato, con unalta percentuale di successo. La procedura richiede una strumentazione adeguata e deve essere eseguita da un chirurgo esperto, che abbia svolto un training specifico scialoendoscopico, in modo da evitare le possibili complicanze maggiori e minori. La scialectomia tradizionale rappresenta la extrema ratio, limitata nei casi in cui un approccio conservativo sia risultato inefficace o controindicato

Validation of a combined CFD/FEM methodology for the evaluation of thermal load acting on aluminum alloy pistons through hardness measurements in internal combustion engines

This work presents the results of amultidisciplinary research project, carried outin close collaboration with Ducati MotorHolding S.p.A., for the development of anintegrated methodology to design enginecomponents in aluminum alloy under highthermal loads. The results refer to the study ofan AA2618 (Al-Cu-Mg) alloy piston for highperformance motorcycle engines. The pistonhas been selected as the pilot component forthe development and validation of anadvanced Fluid Dynamics (CFD) and FiniteElement (FE) simulation methodology for theprediction of the inner thermal diffusion. Thesubsequent validation has been achievedthrough both the mechanical andmicrostructural characterization of thecomponent. The methodology here presentedconsists of close interaction between fluiddynamics(CFD) simulations of the combustionprocess and Finite Element (FEM) simulations ofthe thermal diffusion inside the components.Combustion is the main engine heat sourceand is simulated by means of a threedimensionalCFD code for reactive flows (FIREv2008-AVL), with the use of advancedcombustion (ECFM) and wall interactionmodels. The temperature map on the surfacesis based on the results of the iteration with FEMsimulation of thermal diffusion. The FEM modelused for the diffusion analysis receives theresults of combustion analysis as input. Twodifferent methods have been tested for thetransfer of the CFD thermal load to the FEMmodels: a) imposition on the piston crown of aspatial distribution of heat flux averaged overthe mean engine cycle; b) imposition on thepiston crown of both heat flux coefficients and..

Imaging the three-dimensional architecture of the Middle Aterno basin (2009 L’Aquila earthquake, Central Italy) using ground TDEM and seismic noise surveys: preliminary results

We present preliminary results from a multidisciplinary geophysical approach applied to the imaging of the threedimensional architecture of the Middle Aterno basin, close to the epicentral area of the 2009 L’Aquila earthquake (central Italy). We collected several time domain electromagnetic soundings (TDEM) coupled with seismic noise measurements focusing on the characterization of the bedrock/infill interface. Our preliminary results agree with existing geophysical data collected in the area, and show that the southeastern portion of the basin is characterized by a deepening of the Mesozoic-Tertiary bedrock down to a depth of more than 450 m. We found that a joint use of electromagnetic and seismic methods significantly contributes in obtaining new insights on the 3D geometry of the Middle Aterno basin. Moreover, we believe that our combined approach based on TDEM and noise measurements can be adopted to investigate similar geological settings elsewhere.PublishedPescina (AQ)2T. Tettonica attivaope

Imaging the three-dimensional architecture of the Middle Aterno basin (2009 L’ Aquila earthquake, Central Italy) using ground TDEM and seismic noise surveys: preliminary results

We present preliminary results from a multidisciplinary geophysical approach ap- plied to the imaging of the three-dimensional architecture of the Middle Aterno basin, close to the epicentral area of the 2009 L’Aquila earthquake (central Italy). We collected several time domain electromagnetic soundings (TDEM) coupled with seismic noise measurements focu- sing on the characterization of the bedrock/in ll interface. Our preliminary results agree with existing geophysical data collected in the area, and show that the southeastern portion of the basin is characterized by a deepening of the Mesozoic-Tertiary bedrock down to a depth of more than 450 m. We found that a joint use of electromagnetic and seismic methods signi - cantly contributes in obtaining new insights on the 3D geometry of the Middle Aterno basin. Moreover, we believe that our combined approach based on TDEM and noise measurements can be adopted to investigate similar geological settings elsewhere.PublishedPescina (AQ), Italy2T. Tettonica attiva3T. Pericolosità sismica e contributo alla definizione del rischio7A. Geofisica di esplorazioneope