Correction of spatial distortion in magnetic resonance imaging

Dissertation to Obtain the Degree of Master in Biomedical Engineering

Characterization of Pinus spp. needles by gas chromatography and mass spectrometry: Application to plant-insect interactions

Dissertação apresentada para obtenção do Grau de Doutor em Ciências do Ambiente pela Universidade Nova de Lisboa, Faculdade de Ciências e Tecn

Airborne fungi in the city of Porto Alegre, Rio Grande do Sul, Brazil

Knowledge of anemophilous fungi in a given city or region is important for the ecological diagnosis and specific treatment of allergic manifestations induced by inhaled allergens. In order to diagnose the presence of anemophilous fungi, several qualitative and quantitative techniques are used depending on the study place. This study of fungal air spores was performed with a Rotorod Sampler®, an equipment which samples the air through a plastic rod attached to an electric engine that makes it spin fast enough to collect the particles in the air. The samples were collected once a week during 24 hours using the standard cycle of the manufacturers. A total of 52 samples were obtained from April 2000 through March 2001. The results revealed prevalence of ascosporos (50.49%), Cladosporium (17.86%), Aspergillus/Penicillium (15.03%), basidiosporos (3.84%), rusts (3.82%), and Helminthosporium (2.49%), and a lesser frequency of Botrytis (1.22%), Alternaria (1.19%), smuts (0.90%), Curvularia (0.87%), Nigrospora (0.61%), and Fusarium (0.08%). Also, 1.59% of the spores detected here could not be identified by the systematic key used. More fungal spores were observed during the summer than during the autumn.

Chromatin dynamics in Arbidopsis development: a live cell imaging approach

Dissertation presented to obtain the Ph.D degree in Biology

Airborne fungi isolated from Fortaleza city, State of Ceará, Brazil

Airbone fungi are considered important causes of allergic rhinitis and allergic asthma. The knowledge of these fungi in a city or region is important for the ecological diagnosis and specific treatment of allergic manifestations induced by inhalation of fungal allergens. The airborne fungi of Fortaleza, State of Ceará, Brazil, were studied during a one year period. Five hundred and twenty Petri dishes with Sabouraud dextrose agar medium were exposed at ten different locations in the city. The dishes exposed yielded one thousand and five hundred and twenty one colonies of twenty four genera. The most predominants were: Aspergillus (44.7%), Penicillium (13.3%), Curvularia (9.8%), Cladosporium (6.8%), Mycelia sterilia (6.0%), Fusarium (3.5%), Rhizopus (3.1%), Drechslera (2.6%), Alternaria (2.4%) and Absidia (2.2%). The results shown that Aspergillus, Penicillium, Mycelia sterilia, Fusarium and Alternaria were found during all months in the year. Absidia was more frequent during the dry season. Anemophilous fungi and the high concentration of spores in the air are important because may result in an increased number of people with allergic respiratory disease.

Magnetic Resonance Imaging and Gynecological Devices

Background: Performing magnetic resonance imaging (MRI) on women with gynecological devices is a completely accepted practice. The goal of our review is to assess how safe it is to perform MRI on women using contraceptive implants or devices. Study Design: Literature review, searching in PubMed-Medline/Ovid for the following keywords: magnetic resonance imaging, intrauterine devices, Implanon® and Essure®. Results: Though plastic devices do not represent a contraindication to the use of the technique, those including metallic components have been submitted to several tests, after which they were classified as MR Conditional (devices presenting no risks in MR-specific environments) by the Food and Drug Administration. Thus, the use of MRI can be safely advised to women with this type of device as long as the magnetic resonance equipment is ≤3.0 T. Conclusions: Presently, there is no scientific evidence that contraindicates performing MRI on women with any kind of gynecological device. Therefore, this procedure is safe as long as it is performed under previously tested conditions.

An Update on Airborne Contact Dermatitis: 2001-2006

Reports on airborne dermatoses are mainly published in the context of occupational settings. Hence, in recent years, dermatologists and also occupational physicians have become increasingly aware of the airborne source of contact dermatitis, resulting mainly from exposure to irritants or allergens. However, their occurrence is still underestimated, because reports often omit the term 'airborne' in relation to dust or volatile allergens. For the present update, we screened the journals 'Contact Dermatitis' (July 2000 to December 2006); 'Dermatitis', formerly named 'American Journal of Contact Dermatitis'; 'La Lettre du Gerda' (January 2000 to December 2006); and also included relevant articles from other journals published during the same period. This resulted in an updated list of airborne dermatitis causes.

Prostatic Arterial Supply: Anatomic and Imaging Findings Relevant for Selective Arterial Embolization

PURPOSE: To describe the anatomy and imaging findings of the prostatic arteries (PAs) on multirow-detector pelvic computed tomographic (CT) angiography and digital subtraction angiography (DSA) before embolization for symptomatic benign prostatic hyperplasia (BPH). MATERIALS AND METHODS: In a retrospective study from May 2010 to June 2011, 75 men (150 pelvic sides) underwent pelvic CT angiography and selective pelvic DSA before PA embolization for BPH. Each pelvic side was evaluated regarding the number of independent PAs and their origin, trajectory, termination, and anastomoses with adjacent arteries. RESULTS: A total of 57% of pelvic sides (n = 86) had only one PA, and 43% (n = 64) had two independent PAs identified (mean PA diameter, 1.6 mm ± 0.3). PAs originated from the internal pudendal artery in 34.1% of pelvic sides (n = 73), from a common trunk with the superior vesical artery in 20.1% (n = 43), from the anterior common gluteal-pudendal trunk in 17.8% (n = 38), from the obturator artery in 12.6% (n = 27), and from a common trunk with rectal branches in 8.4% (n = 18). In 57% of pelvic sides (n = 86), anastomoses to adjacent arteries were documented. There were 30 pelvic sides (20%) with accessory pudendal arteries in close relationship with the PAs. No correlations were found between PA diameter and patient age, prostate volume, or prostate-specific antigen values on multivariate analysis with logistic regression. CONCLUSIONS: PAs have highly variable origins between the left and right sides and between patients, and most frequently arise from the internal pudendal artery.

Susceptibility-Weighted Imaging - Aplicações em Neuropediatria

de imagem em RM, caracterizada pela sua alta resolução espacial e grande sensibilidade a diferenças de susceptibilidade magnética dos tecidos, acentuando as propriedades paramagnéticas de produtos como a desoxihemoglobina, hemossiderina, ferro e cálcio e sendo particularmente útil na avaliação das estruturas venosas. Objectivos: O objectivo deste trabalho é fazer uma breve revisão das aplicações clínicas da sequência SWI em neuropediatria e demonstrar a sua grande utilidade, nomeadamente em comparação as a sequência T2*. Material e Métodos: Os exames foram realizados a crianças com idades compreendidas entre o período neonatal e os 16 anos, internadas ou seguidas em consulta no Hospital Pediátrico D. Estefânia; as imagens SWI foram efectuadas em equipamento Siemens 1.5 T, Avanto, com os seguintes parâmetros: TR 49, TE 40, flip angle 15, espessura 1,6mm. Resultados: Apresentamos vários casos ilustrativos de patologias em que o SWI demonstra a sua utilidade e mais-valia, nomeadamente na detecção de lesões hemorrágicas recentes ou antigas em diferentes contextos particulares em neuropediatria (patologia hipoxico-isquémica, vascular, trauma não acidental), detecção de cavernomas e anomalias venosas de desenvolvimento, avaliação de tumores e doenças neurodegenerativas. Conclusão: A sequência SWI é bastante útil na avaliação imagiológica de várias patologias e variantes venosas em neuropediatria, fornecendo uma informação adicional com implicações diagnósticas e prognósticas comparativamente com o T2*, obviando também a administração de contraste para avaliação de estruturas venosas.

Application of Infrared Thermal Imaging in a Violinist with Temporomandibular Disorder

Temporomandibular disorders (TMD) consist of a group of pathologies that affect the masticatory muscles, temporomandibular joints (TMJ), and/or related structures. String instrumentalists, like many orchestra musicians, can spend hours with head postures that may influence the biomechanical behavior of the TMJ and the muscles of the craniocervicomandibular complex (CCMC). The adoption of abnormal postures acquired during performance by musicians can lead to muscular hyperactivity of the head and cervical muscles, with the possible appearance of TMD. Medical infrared thermography is a non-invasive procedure that can monitor the changes in the superficial tissue related to blood circulation and may serve as a complement to the clinical examination. The objective of this study was to use infrared thermography to evaluate, in one subject, the cutaneous thermal changes adjacent to the CCMC that occur before, during, and after playing a string instrument.

Stenosis of the Branches of the Neopulmonary Artery after the Arterial Switch Operation: a Cardiac Magnetic Resonance Imaging Study

Background : The neonatal arterial switch operation (ASO) is now the standard of care for children born with transposition of the great arteries. Stenosis of the neopulmonary artery on long‑term follow up is a known complication. Methods : We performed a retrospective analysis of eleven patients who underwent a cardiac magnetic resonance imaging (MRI) due to echocardiographic evidence suggestive of stenosis of the neopulmonary artery or its branches (mean estimated Doppler gradient 48 mmHg, min 30 mmHg, max 70 mmHg). A comprehensive evaluation of anatomy and perfusion was done by cardiac MRI. Results : The branches of the neopulmonary artery (neo PA) showed decreased caliber in three patients unilaterally and in two patients, bilaterally. Magnetic resonance (MR) perfusion studies showed concomitant decreased flow, with discrepancy between the two lungs of 35/65% or worse, only in the three patients with unilateral obstruction, by two different MR perfusion methods. Conclusions : Cardiac MR can be used as a comprehensive non‑invasive imaging technique to diagnose stenosis of the branches of the neopulmonary after the ASO, allowing evaluation of anatomy and function of the neoPA, its branches, and the differential perfusion to each lung, thus facilitating clinical decision making.

Predicting Outcome after Cardiopulmonary Arrest in Therapeutic Hypothermia Patients: Clinical, Electrophysiological and Imaging Prognosticators

INTRODUCTION: Predicting outcome in comatose survivors of cardiac arrest is based on data validated by guidelines that were established before the era of therapeutic hypothermia. We sought to evaluate the predictive value of clinical, electrophysiological and imaging data on patients submitted to therapeutic hypothermia. MATERIALS AND METHODS: A retrospective analysis of consecutive patients receiving therapeutic hypothermia during years 2010 and 2011 was made. Neurological examination, somatosensory evoked potentials, auditory evoked potentials, electroencephalography and brain magnetic resonance imaging were obtained during the first 72 hours. Glasgow Outcome Scale at 6 months, dichotomized into bad outcome (grades 1 and 2) and good outcome (grades 3, 4 and 5), was defined as the primary outcome. RESULTS: A total of 26 patients were studied. Absent pupillary light reflex, absent corneal and oculocephalic reflexes, absent N20 responses on evoked potentials and myoclonic status epilepticus showed no false-positives in predicting bad outcome. A malignant electroencephalographic pattern was also associated with a bad outcome (p = 0.05), with no false-positives. Two patients with a good outcome showed motor responses no better than extension (false-positive rate of 25%, p = 0.008) within 72 hours, both of them requiring prolonged sedation. Imaging findings of brain ischemia did not correlate with outcome. DISCUSSION: Absent pupillary, corneal and oculocephalic reflexes, absent N20 responses and a malignant electroencephalographic pattern all remain accurate predictors of poor outcome in cardiac arrest patients submitted to therapeutic hypothermia. CONCLUSION: Prolonged sedation beyond the hypothermia period may confound prediction strength of motor responses.

Technology governance in radiology: the example of magnetic resonance imaging

Based on the report for the unit “Project III” of the PhD programme on Technology Assessment in 2011. The unit was supervised by Prof. António B. Moniz (FCT-UNL).