Reproducibility analysis of the computerized tomography angiography-derived left atrial wall thickness maps.

Background: Adapting the ablation index (AI) to the left atrial wall thickness (LAWT) derived from computed tomography angiography (CTA) allows for a personalized approach that showed to improve PVI safety and outcomes.

Methods: Three observers with different degrees of experience performed complete LAWT analysis of CTA for 30 patients and repeated the analysis for 10 of these patients. Intra- and inter-observer reproducibility of these segmentations was assessed.

Scientists' warning against the society of waste.

The metabolism of contemporary industrialized societies, that is their energy and material flows, leads to the overconsumption and waste of natural resources, two factors often disregarded in the global ecological equation. In this Discussion article, we examine the amount of natural resources that is increasingly being consumed and wasted by humanity, and propose solutions to reverse this pattern. Since the beginning of the 20th century, societies, especially from industrialized countries, have been wasting resources in different ways.

SYLVIUS: A multimodal and multidisciplinary platform for epilepsy surgery.

Background And Objective: We present SYLVIUS, a software platform intended to facilitate and improve the complex workflow required to diagnose and surgically treat drug-resistant epilepsies. In complex epilepsies, additional invasive information from exploration with stereoencephalography (SEEG) with deep electrodes may be needed, for which the input from different diagnostic methods and clinicians from several specialties is required to ensure diagnostic efficacy and surgical safety. We aim to provide a software platform with optimal data flow among the different stages of epilepsy surgery to provide smooth and integrated decision making.

On the Use of Digital Subtraction Angiography in Stereoelectroencephalography Surgical Planning to Prevent Collisions with Vessels.

Objective: Stereoelectroencephalography (SEEG) consists of the implantation of microelectrodes for the electrophysiological characterization of epileptogenic networks. To reduce a possible risk of intracranial bleeding by vessel rupture during the electrode implantation, the stereotactic trajectories must follow avascular corridors. The use of digital subtraction angiography (DSA) for vascular visualization during planning is controversial due to the additional risk related to this procedure.

Scar Characterization to Predict Life-Threatening Arrhythmic Events and Sudden Cardiac Death in Patients With Cardiac Resynchronization Therapy: The GAUDI-CRT Study.

Objectives: The aim of this study was to analyze whether scar characterization could improve the risk stratification for life-threatening ventricular arrhythmias and sudden cardiac death (SCD).

Background: Among patients with a cardiac resynchronization therapy (CRT) indication, appropriate defibrillator (CRT-D) therapy rates are low.

Methods: Primary prevention patients with a class I indication for CRT were prospectively enrolled and assigned to CRT-D or CRT pacemaker according to physician's criteria.

Computation of the change in length of a braided device when deployed in realistic vessel models.

Purpose: An important issue in the deployment of braided stents, such as flow diverters, is the change in length, also known as foreshortening, underwent by the device when is released from the catheter into a blood vessel. The position of the distal end is controlled by the interventionist, but knowing a priori the position of the proximal end of the device is not trivial. In this work, we assess and validate a novel computer method to predict the length that a braided stent will adopt inside a silicon model of an anatomically accurate vessel.

A three-dimensional computer-based perspective of the skull base.

Objective: To describe our designed protocol for the reconstruction of three-dimensional (3D) models applied to various endoscopic endonasal approaches that allows performing a 3D virtual dissection of the desired approach and analyzing and quantifying critical surgical landmarks.

Methods: All human cadaveric heads were dissected at the Laboratory of Surgical Neuroanatomy of the University of Barcelona. The dissection anatomic protocol was designed as follows: 1) virtual surgery simulation systems, 2) navigated cadaver dissection, and 3) postdissection analysis and quantification of data.

Extended endoscopic endonasal approaches for cerebral aneurysms: anatomical, virtual reality and morphometric study.

Introduction: The purpose of the present contribution is to perform a detailed anatomic and virtual reality three-dimensional stereoscopic study in order to test the effectiveness of the extended endoscopic endonasal approaches for selected anterior and posterior circulation aneurysms.

Methods: The study was divided in two main steps: (1) simulation step, using a dedicated Virtual Reality System (Dextroscope, Volume Interactions); (2) dissection step, in which the feasibility to reach specific vascular territory via the nose was verified in the anatomical laboratory.

Results: Good visualization and proximal and distal vascular control of the main midline anterior and posterior circulation territory were achieved during the simulation step as well as in the dissection step (anterior communicating complex, internal carotid, ophthalmic, superior hypophyseal, posterior cerebral and posterior communicating, basilar, superior cerebellar, anterior inferior cerebellar, vertebral, and posterior inferior cerebellar arteries).

Synthesis of trigeneration systems: sensitivity analyses and resilience.

This paper presents sensitivity and resilience analyses for a trigeneration system designed for a hospital. The following information is utilized to formulate an integer linear programming model: (1) energy service demands of the hospital, (2) technical and economical characteristics of the potential technologies for installation, (3) prices of the available utilities interchanged, and (4) financial parameters of the project. The solution of the model, minimizing the annual total cost, provides the optimal configuration of the system (technologies installed and number of pieces of equipment) and the optimal operation mode (operational load of equipment, interchange of utilities with the environment, convenience of wasting cogenerated heat, etc.

Use of perfusion bioreactors and large animal models for long bone tissue engineering.

Tissue engineering and regenerative medicine (TERM) strategies for generation of new bone tissue includes the combined use of autologous or heterologous mesenchymal stem cells (MSC) and three-dimensional (3D) scaffold materials serving as structural support for the cells, that develop into tissue-like substitutes under appropriate in vitro culture conditions. This approach is very important due to the limitations and risks associated with autologous, as well as allogenic bone grafiting procedures currently used. However, the cultivation of osteoprogenitor cells in 3D scaffolds presents several challenges, such as the efficient transport of nutrient and oxygen and removal of waste products from the cells in the interior of the scaffold.

Three-dimensional architecture of scar and conducting channels based on high resolution ce-CMR: insights for ventricular tachycardia ablation.

Background: Conducting channels are the target for ventricular tachycardia (VT) ablation. Conducting channels could be identified with contrast enhanced-cardiac magnetic resonance (ce-CMR) as border zone (BZ) corridors. A 3-dimensional (3D) reconstruction of the ce-CMR could allow visualization of the 3D structure of these BZ channels.

A novel bidirectional continuous perfusion bioreactor for the culture of large-sized bone tissue-engineered constructs.

This works reports the development and preliminary assessment of a new bioreactor for culturing large-sized three-dimensional constructs in bone tissue engineering. The bidirectional continuous perfusion bioreactor (BCPB) promotes mechanical stimulation of cells through the creation of shear forces induced by flow perfusion. The main innovation consists in the possibility of culturing scaffolds of large dimensions that can be suitable for the regeneration of critical sized defects.

Image-guided neurosurgery with 3-dimensional multimodal imaging data on a stereoscopic monitor.

Background: In the past 2 decades, intraoperative navigation technology has changed preoperative and intraoperative strategies and methodology tremendously.

Objective: To report our first experiences with a stereoscopic navigation system based on multimodality-derived, patient-specific 3-dimensional (3-D) information displayed on a stereoscopic monitor and controlled by a virtual user interface.

Methods: For the planning of each case, a 3-D multimodality model was created on the Dextroscope.

Molecular evidence to suggest the origin of a colonization: Drosophila subobscura in America.

The recent colonization of America by Drosophila subobscura represents a great opportunity for evolutionary biology studies. Knowledge of the populations from which the colonization started would provide an understanding of how genetic composition changed during adaptation to the new environment. Thus, a 793 nucleotide fragment of the Odh (Octanol dehydrogenase) gene was sequenced in 66 chromosomal lines from Barcelona (western Mediterranean) and in 66 from Mt.

Validation of the Basic Psychological Needs in Exercise Scale in a Portuguese sample.

In line with self-determination theory (SDT: Deci & Ryan, 1985, 2002) the satisfaction of the basic psychological needs for autonomy, competence, and relatedness has been identified as an important predictor of behavior and optimal functioning in various contexts including exercise. The lack of a valid and reliable instrument to assess the extent to which these needs are fulfilled among Portuguese exercise participants limits the evaluation of causal links proposed by SDT in the Portuguese exercise context. The aim of the present study was to translate into Portuguese and validate the Basic Psychological Needs in Exercise Scale (BPNES: Vlachopoulos & Michailidou, 2006).

Glucagonoma syndrome: a case report.

Introduction: Glucagonoma syndrome is a rare paraneoplastic phenomenon, with an estimated incidence of one in 20 million, characterized by necrolytic migratory erythema, hyperglucagonemia, diabetes mellitus, anemia, weight loss, glossitis, cheilitis, steatorrhea, diarrhea, venous thrombosis and neuropsychiatric disturbances in the setting of a glucagon-producing alpha-cell tumor of the pancreas. Necrolytic migratory erythema is the presenting manifestation in the majority of cases, so its early suspicion and correct diagnosis is a key factor in the management of the patient.

Case Presentation: We present the case of a 70-year-old Caucasian woman with glucagonoma syndrome due to an alpha-cell tumor located in the tail of the pancreas, successfully treated with surgical resection.

Neurosurgical craniotomy localization using a virtual reality planning system versus intraoperative image-guided navigation.

Purpose: Accurate craniotomy placement is essential for frameless neuronavigation in minimally invasive neurosurgery. A craniotomy using virtual reality (VR) can be as accurate as neuronavigation.

Methods: We prospectively enrolled 48 patients that underwent minimally invasive cranial procedures planned using VR, followed by neuronavigation.

Dex-ray: augmented reality neurosurgical navigation with a handheld video probe.

Objective: We developed an augmented reality system that enables intraoperative image guidance by using 3-dimensional (3D) graphics overlaid on a video stream. We call this system DEX-Ray and report on its development and the initial intraoperative experience in 12 cases.

Methods: DEX-Ray consists of a tracked handheld probe that integrates a lipstick-size video camera.

Evolution of Chilean colonizing populations of Drosophila subobscura: lethal genes and chromosomal arrangements.

Knowledge of the frequency, distribution, and fate of lethal genes in chromosomal inversions helps to illuminate the evolution of recently founded populations. We analyze the relationship between lethal genes and inversions in two colonizing populations of D. subobscura in Chile.

A collaborative virtual reality environment for neurosurgical planning and training.

Objective: We have developed a highly interactive virtual environment that enables collaborative examination of stereoscopic three-dimensional (3-D) medical imaging data for planning, discussing, or teaching neurosurgical approaches and strategies.

Materials And Methods: The system consists of an interactive console with which the user manipulates 3-D data using hand-held and tracked devices within a 3-D virtual workspace and a stereoscopic projection system. The projection system displays the 3-D data on a large screen while the user is working with it.

Global genetic change tracks global climate warming in Drosophila subobscura.

Comparisons of recent with historical samples of chromosome inversion frequencies provide opportunities to determine whether genetic change is tracking climate change in natural populations. We determined the magnitude and direction of shifts over time (24 years between samples on average) in chromosome inversion frequencies and in ambient temperature for populations of the fly Drosophila subobscura on three continents. In 22 of 26 populations, climates warmed over the intervals, and genotypes characteristic of low latitudes (warm climates) increased in frequency in 21 of those 22 populations.

Contouring in 2D while viewing stereoscopic 3D volumes.

The ability to manually specify contours in a volumetric data is often required in situations when automatic algorithms are unable to accurately extract the desire volume. Conventionally, the contours are drawn over a slice, working on plane-by-plane basis usually constrained to orthogonal planes. In defining the contour on a 2D image, the user faces the problem of loosing 3D context (does the tissue belong to inside the contour or outside?).

Temperature-related genetic changes in laboratory populations of Drosophila subobscura: evidence against simple climatic-based explanations for latitudinal clines.

Parallel latitudinal clines to the long-standing ones in the original Palearctic populations have independently evolved at different rates for chromosomal polymorphism and body size in South and North American populations of Drosophila subobscura since colonization around 25 years ago. This strongly suggests that (micro) evolutionary changes are largely predictable, but the underlying mechanisms are unknown. The putative role of temperature per se was investigated by using three sets of populations at each of three temperatures (13 degrees , 18 degrees , and 22 degrees C) spanning much of the tolerable range for this species.

[Evaluation of diabetic foot amputation rate].

In 1987, it was created the first portuguese Diabetic Foot Clinic in Oporto, at the Hospital Geral de Santo António. The distinction between neuropathic and ischaemic foot was the key stone to reduce drastically the rate of major amputations in the first two years of activity. Since then and until 1995 the rate of major amputations had stabilised around 8%.

Colonization of America by Drosophila subobscura: association between Odh gene haplotypes, lethal genes and chromosomal arrangements.

The colonization of America by Drosophila subobscura has been a unique exper iment in nature that has allowed us to explore the effects of evolution on a continental scale. To analyze this evolutionary event, nucleotide sequences of the Odh (Octanol dehydrogenase) gene were obtained for 43 lethal chromosomal lines from colonizing populations of North America and 5 from South America, in addition to 5 chromosomal lines from Europe with different viabilities and 2 from laboratory marker stocks. Since 10 different Odh haplotypes were found in America, the minimum number of colonizers would be 5 (or 3 mated females).