Hugo Alexandre Ferreira

Hugo Alexandre Ferreira
University of Lisbon | UL · Faculty of Science

MD, MScEng, PhD

About

197
Publications
20,973
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2,413
Citations
Introduction
Skills and Expertise
Additional affiliations
May 2009 - present
University of Lisbon
Position
  • Professor (Assistant)
Description
  • Post-doc from May 2009 to December 2011. Assistant Professor since December 2011.

Publications

Publications (197)
Article
Aerogels are materials with unique properties, among which are low density and thermal conductivity. They are also known for their exquisite biocompatibility and biodegradability. All these features make them attractive for biomedical applications, such as their potential use in photothermal therapy (PTT). This technique is, yet, still associated w...
Article
Full-text available
Functional brain connectivity (FBC) has previously been examined in autism spectrum disorder (ASD) between-resting-state networks (RSNs) using a highly sensitive and reproducible hypothesis-free approach. However, results have been inconsistent and sex differences have only recently been taken into consideration using this approach. We estimated ma...
Article
Full-text available
Breast cancer is a high-burden malignancy for society, whose impact boosts a continuous search for novel diagnostic and therapeutic tools. Among the recent therapeutic approaches, photothermal therapy (PTT), which causes tumor cell death by hyperthermia after being irradiated with a light source, represents a high-potential strategy. Furthermore, t...
Article
Full-text available
Deciding whether others’ emotions are genuine is essential for successful communication and social relationships. While previous fMRI studies suggested that differentiation between authentic and acted emotional expressions involves higher-order brain areas, the time course of authenticity discrimination is still unknown. To address this gap, we tes...
Article
Full-text available
The global impact of cancer emphasizes the importance of developing innovative, effective and minimally invasive therapies. In the context of superficial cancers, the development of a multifunctional nanoparticle-based system and its in vitro and in vivo safety and efficacy characterization are, herein, proposed as a proof-of-concept. This multifun...
Article
The presence of brain amyloid‐beta plaques is relevant for the diagnosis of Alzheimer’s Disease (AD) [1‐3]. However, positron emission tomography (PET), used to assess amyloid loading, is expensive and not widely available as other imaging modalities [2]. Therefore, the aim of this study was to assess if magnetic resonance imaging (MRI) morphometri...
Thesis
Full-text available
Speech processing can be disturbed by primary brain tumors (PBT). Improvement of presurgical planning techniques decrease neurological morbidity associated to tumor resection during awake craniotomy. The aims of this work were: 1. To perform Diffusion Kurtosis Imaging based tractography (DKI-tract) in the detection of brain tracts involved in lang...
Article
Background and Study Aims Cortical mapping (CM) with direct cortical stimulation (DCS) in awake craniotomy is used to preserve cognitive functions such as language. Nevertheless, patient collaboration during this procedure is influenced by previous neurological symptoms and growing discomfort with DCS duration. Our study aimed to evaluate the impac...
Poster
The microcirculation regulatory mechanisms are still poorly understood despite being central in the understanding of vascular physiology and pathophysiology. One practical way to study these mechanisms is through the acquisition of continuous blood flow signals with noninvasive techniques such as laser Doppler flowmetry (LDF). These signals can the...
Poster
Vessel topography is important in vascular medicine given the vascular abnormalities found in many developmental and cardiovascular diseases as well in ageing. Branching regions of any vascular tree are common sites for lesion due to the increased turbulent flow leading to dysmorphic features and dysfunction. Magnetic resonance imaging (MRI) is a p...
Poster
Microcirculation perfusion signals are oscillatory and complex in nature, reflecting the activity of highly dynamic regulation phenomena. Consequently, there is a constant need to obtain quantitative parameters to better translate properties such as fractality and complexity. These parameters are often difficult to interpret themselves, which precl...
Chapter
The identification of biomarkers to discriminate Parkinson’s Disease from other motor diseases is crucial to provide suitable treatment to patients. This study proposes a novel approach for the classification of structural Magnetic Resonance Imaging (MRI), Dopamine Transporter scan data (DaTscan) and demographic information (age and gender) to diff...
Article
Massage is commonly used as a complementary therapy for many different conditions. Demonstration of its physiological impact and understanding of its therapeutic mechanisms is still insufficient and often inconclusive. This study aims to characterize the physiological effects of effleurage, one of the most popular techniques, on human in vivo micro...
Article
Full-text available
The quantitative assessment of cardiovascular functions is particularly complicated, especially during any physiological challenge (e.g., exercise), with physiological signals showing intricate oscillatory properties. Signal complexity is one of such properties, and reflects the adaptability of the physiological systems that generated them. However...
Chapter
The diagnosis of Parkinsonian Syndromes (PS) at early-stages is a challenge. PS usually present similar symptoms, and the diagnosis is mainly clinical, causing often misdiagnosis between PS and other movement disorders. Parkinson’s Disease (PD) is the most common PS, affecting a large part of the worldwide population. Medical imaging such as Magnet...
Chapter
Full-text available
Abstract. All those that work in markets research know, for long, that there is a distance between the intentions that consumers manifest overtly (e.g. in surveys or focus groups) and what they practise. One cause is that these methods assume the consumer as a full rational decision-maker, although most consumption acts arise in the non-conscious p...
Article
Background: Brain volumes have been used as research biomarkers both in health and in Alzheimer's disease(AD). In order to improve the comparability between studies and aid future analytical software platform choice in the research setting, here we compare two segmentation pipelines of structural brain magnetic resonance imaging(sMRI): the SPM12 t...
Article
Full-text available
Laser Doppler flowmetry (LDF) and reflection photoplethysmography (PPG) are standard technologies to access microcirculatory function in vivo. However, different light frequencies mean different interaction with tissues, such that LDF and PPG flowmotion curves might have distinct meanings, particularly during adaptative (homeostatic) processes. The...
Poster
The wavelet transform analysis (WT) of optical phenomena gathered from techniques such as laser Doppler flowmetry (LDF) is well known, and regarded as a useful mechanistic assessment refinement. In the present study we applied this strategy to one other technology, photoplethysmography (PPG) and compare it with equivalent signals obtained under the...
Poster
Recent studies identified a contralateral response observed in the veno arterial reflex in the test limb, both in animals and humans. This adaptative reflex is known for a long time but its mechanistic explanation is still unclear. In the present study we assessed this reflex as a function of age. 8 healthy volunteers (mean 50.13 ± 6.17 yo) from bo...
Poster
Effleurage is surely one of the most popular massage techniques used for multiple purposes. Its physiological impact and mechanisms are still poorly understood, sometimes inconclusive. We aim to characterize the cardiovascular impact of this technique on human in vivo microcirculation. To this end, distal blood perfusion was non invasively quantifi...
Presentation
Microcirculation is often assessed by noninvasive technologies such as laser Doppler flowmetry (LDF), laser Doppler perfusionimaging (LDPI), photoplethysmography (PPG) and, more recently, polarized light spectroscopy (PLS). LDF and PPG measure perfusion in a small tissue region on a continuous mode, producing complex and multiscaled oscillatory sig...
Poster
The study of vessel topography is of great importance in vascular medicine since vascular abnormalities or dysmorphic features are present in many developmental and cardiovascular disorders, as well as in ageing, even when no clinical manifestations are present. Branching regions of any vascular tree is a common site for architectural dysmorphia an...
Chapter
One of the greatest challenges in the study of emotions and emotional states is their measurement. The techniques used to measure emotions depend essentially on the authors’ definition of the concept of emotion. Currently, two types of measures are used: subjective and objective. While subjective measures focus on assessing the conscious recognitio...
Article
Diffusion kurtosis imaging (DKI) is a diffusion-weighted MRI technique that probes the non-Gaussian diffusion of water molecules within biological tissues. The purpose of this study was to investigate the DKI model optimal b-values combinations in invasive ductal carcinoma (IDC) versus ductal carcinoma in situ (DCIS) breast lesions. The study inclu...
Poster
Full-text available
INTRODUCTION A Evidences of a so called limb collaboration between both lower limbs has been observed in human, during a venoarterial reflex protocol 1 where significant perfusion reductions were note in both test and control foot in young healthy individuals The same phenomena was depicted by the hyperoxia mouse model, following a hindlimb ischemi...
Poster
Full-text available
INTRODUCTION Recently, a lower limb collaboration was observed with a venoarterial reflex protocol 1 , where significant perfusion reductions were note both in the test as in the control foot of young healthy individuals. The same group demonstrated, by the hyperoxia mouse model, a similar effect following a hindlimb ischemia procedure 2. In the pr...
Article
Full-text available
The low-cost multimodal platform BITalino is being increasingly used for educational and research purposes. However, there is still a lack of well-structured work comparing data acquired by this toolkit against a reference device, using established experimental protocols. This work intends to fill said gap by benchmarking the performance of BITalin...
Article
Full-text available
Modelling is essential for a better understanding of microcirculatory pathophysiology. In this study we tested our hyperoxia-mouse model with healthy and non-healthy mice. Animals (n = 41) were divided in groups—a control group, with 8 C57/BL6 non-transgenic male mice, a diabetic group (DB), with 8 C57BLKsJ-db/db obese diabetic mice and the corresp...
Data
P11 - Studying the Venoarteriolar reflex as part of the in vivo regulation mechanism of pheripheral circulation
Chapter
In this chapter, an overview of the opportunities and challenges of parametric imaging in positron emission tomography (PET) and magnetic resonance (MR) is presented. Parametric imaging, together with the reasons why it is necessary and important, is introduced. In PET, concepts such as dynamic PET and the typical processing steps are explained. Th...
Article
Background The gamma distribution (GD) model is based on the statistical distribution of the apparent diffusion coefficient (ADC) parameter. The GD model is expected to reflect the probability of the distribution of water molecule mobility in different regions of tissue, but also the intra‐ and extracellular diffusion and perfusion components (f1,...
Article
Full-text available
A circulatory adaptation affecting the circulation of both lower limbs seems to be part of a distal circulatory homeostatic mechanisms, in animals as in humans. This was also observed during massage with the contralateral limb responding similarly to the intervened limb. The present study is meant to explore this cooperation between limbs during ma...
Article
Full-text available
Understanding diffusion processes is particularly important for clinical imaging to distinguish between healthy and pathological tissues or between benign and malignant lesions. Computational models of diffusion allow us to predict specific architectural properties of biological tissues which correlate to the measured values of diffusion imaging, t...
Poster
Full-text available
INTRODUCTION A particular perfusion dynamic, responsible for a circulatory steady state between both hind limbs has been described in human, regarded as a long-term vascular adaptation to ischemia in patients with peripheral arterial occlusive disease. More recently, similar observations were described in the human foot as a consequence of postural...
Article
Full-text available
Perfusion at microvascular level involves the contribution of both local and central regulators, under a complex vascular signaling frame. The venoarteriolar reflex (VAR) is one of such regulatory responses, of particular relevance in the lower limb to prevent edema. Although known for quite some time, many of the complex interactions involving all...
Article
Full-text available
This study combines two well‐known vascular research models, hyperoxia and hind limb ischemia, aiming to better characterize capacities of the hyperoxia challenge. We studied two groups of C57/BL6 male mice, a control (C) and a hind limb ischemia (HLI) group. Perfusion from both limbs was recorded in all animals by laser Doppler techniques under an...
Article
Full-text available
Non-invasive optical techniques, such as LDF (laser Doppler flowmetry) and PPG (photoplethysmography) are leading technologies to assess the human microcirculation. New mathematical strategies for signal processing such as WT (wavelet transform) have been developed to enhance its quantification capabilities. We have dedicated some effort to better...
Poster
Full-text available
The effects of massage on microcirculation are far from being fully understood, although its therapeutic use has a long history. In this study, we assess the effects of the hind limb massage by noninvasive technologies such as laser Doppler flowmetry (LDF) and photoplethysmography (PPG). We also perform a spectral decomposition of the signals using...
Article
Introduction Utterance of a word may be an involuntary action. We hypothesize that, once pronunciation of a word is fully prepared it can be triggered as a reflex with no need for cortical processing. Methods We used modified protocols of picture naming tasks, with different levels of cognitive demands, to measure the reaction time of word pronunc...
Article
Introduction Language production involves a complex brain network that should be taken into account in pre-surgical planning of patients with brain tumors. Connectivity analysis (functional and structural) of magnetic resonance imaging data (cMRI) enables the study of the functional interaction and structural relationship between brain regions. Our...
Article
In certain circumstances, words can be uttered as an involuntary action. We hypothesize that, once pronunciation of a word is fully prepared it can be triggered as a reflex with no need for cortical processing. We used modified protocols of picture naming tasks, with different levels of cognitive demands, to measure reaction time to word pronunciat...
Poster
Full-text available
Acknowledgments: We would like to express our thanks to the participants, to Sergio Nuno and Rafaela Francisco. This work was supported by national funds from FCT-Fundação para a Ciência e a Tecnologia, I.P, within the project UID/DTP/04567/2016 Massage is an ancient technique, commonly used for health and well-being, namely to improve skin aesthet...
Chapter
Digital game research has been rapidly growing with studies dedicated to game experience and adopting new technologies. Alongside, research in Brain-Computer Interfaces (BCI) is growing in game applications. Besides technical shortcomings, BCI research in gaming can also be lacking due to challenges such as poorly designed games that do not provide...
Article
Full-text available
Tractography studies for pre-surgical planning of primary brain tumors is typically done using diffusion tensor imaging (DTI), which cannot resolve crossing, kissing or highly angulated fibres. Tractography based on the estimation of the diffusion kurtosis (DK) tensor was recently demonstrated to enable tackling these limitations. However, its use...
Article
Purpose: Determining optimal b-value pair for differentiation between normal and prostate cancer (PCa) tissues. Methods: Forty-three patients with diagnosis or PCa symptoms were included. Apparent diffusion coefficient (ADC) was estimated using minimum and maximum b-values of 0, 50, 100, 150, 200, 500s/mm2 and 500, 800, 1100, 1400, 1700 and 2000...
Poster
Full-text available
Massage of the lower limb has a long history of empirical use for a multitude of health / well-being purposes, namely for circulation distress, injury recovery, anxiety relief and pain control. Previous studies observed that it might modify local blood perfusion, but only a few addressed the physiological mechanisms involved, still poorly understoo...
Poster
Full-text available
The skin is known to be an adequate location to address a wide range of functional aspects of microcirculation and, for that reason, laser doppler flowmetry (LDF) and photoplethysmography (PPG) became well-known, non-invasive techniques to quantify flow variables in conditions as close as possible from the normal physiological state. Massage is fre...
Conference Paper
The purpose of this study was to develop a new approach for the identification of the epileptogenic focus using Blood Oxygen Level Dependent (BOLD) signals from functional magnetic resonance imaging (fMRI) data. This novel approach is based on the following hypotheses (1) the epileptogenic focus BOLD signal during the interictal state shows transie...
Conference Paper
Transcranial direct current stimulation (tDCS) has proven to be a useful tool in the scientific research community, particularly for clinical investigation purposes. Neuroimaging studies indicate that there is a connection between the prefrontal cortex (PFC) and working memory (WM), as well as between the primary motor cortex and reaction time (RT)...
Conference Paper
Media has the potential to generate attitudes and emotions and influence our state of mind, our health, happiness and sense of wellbeing, and it is becoming pervasive in our lives. This paper explores the potential of advances in neuroscience and informatics to support people in becoming more aware of and in regulating their emotional states and se...
Poster
Monte-Carlo simulations of diffusion processes have have shown to be useful in characterizing simulated histological environments at the microstructural level. Specifically we estimate breast tumour tissue diffusion parameters from histological images and Monte-Carlo simulations
Article
Purpose This paper aims to explore brain-based differences in national and own-label brands perceptions. Because price is a differentiating characteristic, able to discriminate between national and own-label brands, its influence is also studied. Design/methodology/approach The study uses the Save Holdings Or Purchase (SHOP) task with functional m...
Presentation
Full-text available
Laser Doppler flowmetry (LDF) is a reference technique to quantify in vivo microcirculation, but It provides a highly variable signal, that limits its use. Several strategies have been dedicated to simplify it, but also to look deeper into the information included in those oscillatory components. This study shows how the wavelet transform can decom...
Poster
The murine model of hind limb ischemia is one of the most popular models to study the vascular disease, including new therapies testing. However, published information regarding the murine vascular function regulation and its comparison with human is scarce and, in some cases inexistent. This study evaluates the vascular reactivity of a murine isch...
Poster
Photoplethysmography (PPG) is a well-known technique used for a long time to monitor the individual’s cardiovascular signals. In the last years laser Doppler flowmetry (LDF) and imaging (LDI) almost made us forget about PPG . However, it has the same oscillatory nature of LDF, also a very low cost and easiness to use. In this study, we compare the...
Poster
Postural changes are often employed as dynamical tests to quantify peripheral microcirculation. The leg lowering maneuver has been studied in the past in both health and disease, but many questions remain open. Our objective was to quantify the peripheral vascular response to a leg lowering maneuver on both extremities. Ten subjects (both genders,...
Article
Full-text available
The present model aims to develop and optimize an innovative technological resource. Advanced biometric solutions and innovative technologies specifically designed are implemented, combining bio-direct and bio-indirect signals. The model underpinning is aiming to explore the relationship between states and traits of consciousness, meditative practi...
Article
Full-text available
The skin provides an easy accessible vascular network to assess microcirculation by laser Doppler flowmetry (LDF), and transcutaneous (tc) gasometry, widely known techniques used for this purpose. the objective of this study was to assess and compare the microcirculation status of different age subjects, knowing that the ageing process progressivel...
Poster
Ocasionally, the diagnosis of neuropsychiatric disorders using biomedical imaging techniques is hampered by a number of factors. How to make it easier to interpret their results from a Medical Point-of-View?
Conference Paper
After stroke some people can be left with sequelae, namely hand motor impairments. Present hand motor rehabilitation strategies are limited to the availability of a technician or caregiver for providing support. Additionally, these strategies rely on exercises that are repetitive and long lasting, which could be demotivating for a patient, therefor...