Augusto Silva

Detection and 3D representation of pulmonary air bubbles in HRCT volumes

Bubble emphysema is a disease characterized by the presence of air bubbles within the lungs. With the purpose of identifying pulmonary air bubbles, two alternative methods were developed, using High Resolution Computer Tomography (HRCT) exams. The search volume is confined to the pulmonary volume through a previously developed pulmonary contour detection algorithm. The first detection method follows a slice by slice approach and uses selection criteria based on the Hounsfield levels, dimensions, shape and localization of the bubbles. Candidate regions that do not exhibit axial coherence along at least two sections are excluded. Intermediate sections are interpolated for a more realistic representation of lungs and bubbles. The second detection method, after the pulmonary volume delimitation, follows a fully 3D approach. A global threshold is applied to the entire lung volume returning candidate regions. 3D morphologic operators are used to remove spurious structures and to circumscribe the bubbles. Bubble representation is accomplished by two alternative methods. The first generates bubble surfaces based on the voxel volumes previously detected; the second method assumes that bubbles are approximately spherical. In order to obtain better 3D representations, fits super-quadrics to bubble volume. The fitting process is based on non-linear least squares optimization method, where a super-quadric is adapted to a regular grid of points defined on each bubble. All methods were applied to real and semi-synthetical data where artificial and randomly deformed bubbles were embedded in the interior of healthy lungs. Quantitative results regarding bubble geometric features are either similar to a priori known values used in simulation tests, or indicate clinically acceptable dimensions and locations when dealing with real data.

Fast pulmonary contour extraction in x-ray CT images: a methodology and quality assessment

Segmentation of thoracic X-Ray Computed Tomography images is a mandatory pre-processing step in many automated or semi- automated analysis tasks such us region identification, densitometric analysis, or even for 3D visualization purposes when a stack of slices has to be prepared for surface or volume rendering. In this work, we present a fully automated and fast method for pulmonary contour extraction and region identification. Our method combines adaptive intensity discrimination, geometrical feature estimation and morphological processing resulting into a fast and flexible algorithm. A complementary but not less important objective of this work consisted on a quality assessment study of the developed contour detection technique. The automatically extracted contours were statistically compared to manually drawn pulmonary outlines provided by two radiologists. Exploratory data analysis and non-parametric statistical tests were performed on the results obtained using several figures of merit. Results indicate that, besides a strong consistence among all the quality indexes, there is a wider inter-observer variability concerning both radiologists than the variability of our algorithm when compared to each one of the radiologists. As an overall conclusion we claim that the consistence and accuracy of our detection method is more than acceptable for most of the quantitative requirements mentioned by the radiologists.

Nanoradioliposomes molecularly modulated to study the lung deep lymphatic drainage

Abstract Lung deep lymphatic drainage (LDLD) plays an important role in the removal of foreign materials from lungs being alveolar macrophages the first line of phagocytic defence with high affinity for pathogenic microorganisms. Bacillus subtilis is a well-known genome- decoded saprophyte of the human respiratory tract used in research and in the biotechnology industry. Lung deep lymphatic chains (LDLC) constitute one of the first sites of lung tumours’ dissemination. In this work we intended to develop and validate a non-invasive method for assessing LDLC by nanoradioliposomes aerosolised modulated on the Bacillus subtilis spore wall. The final goal was to produce a nanoradioliposome formulation that can mimics the dynamics of preferential removal of spores by LDLD and present the ideal properties as a tracer for molecular imaging studies. Seven different liposomal formulations were tested, and the formulation-F demonstrated physicochemical and radiopharmaceutical properties that make it an ideal candidate as an in vivo probe for molecular imaging studies of the LDLC. Nanoradioliposomes of the formulation-F after labelling with 99mTc-HMPAO were administered as aerosols to 20 Sus scrofa. Hilar and interpulmonary communications were visualized in first 5 minutes post-inhalation, infradiaphragmatic chains between 10 and 20 minutes, the ganglia of the aortic chain at 20 minutes and those of the renal hilar region at 30 minutes. Conclusion the proposed method enables visualization of deep lymphatic lung network and lymph nodes. Besides, this technique involving the modulation of nanoradioliposomes targeting specific organs or tissues may be an important tool for diagnostic or even for therapeutic purposes.

Cardiology-oriented PACS

This paper describes an integrated system designed to provide efficient means for DICOM compliant cardiac imaging archival, transmission and visualization based on a communications backbone matching recent enabling telematic technologies like Asynchronous Transfer Mode (ATM) and switched Local Area Networks (LANs). Within a distributed client-server framework, the system was conceived on a modality based bottom-up approach, aiming ultrafast access to short term archives and seamless retrieval of cardiac video sequences throughout review stations located at the outpatient referral rooms, intensive and intermediate care units and operating theaters.

Nanorradiolipossomas modulados molecularmente para estudar a drenagem linfática pulmonar profunda

Resumo A drenagem linfatica pulmonar profunda (DLPP) desempenha um papel importante na remocao de materiais estranhos, constituindo os macrofagos alveolares a primeira linha de defesa fagocitaria, dada a grande afinidade para microrganismos patogenicos. Os Bacillus subtilis sao saprofitas do tracto respiratorio humano com ampla utilizacao em investigacao e em biotecnologia. As cadeias linfaticas pulmonares profundas (CLPP) constituem um dos primeiros locais de disseminacao de tumores pulmonares. Neste trabalho pretendeu-se desenvolver e validar um metodo nao invasivo para avaliar as CLPP atraves de nanorradiolipossomas aerosolisados e modulados pela parede do esporo do Bacillus subtilis . O objectivo final foi produzir uma formulacao de nanorradiolipossomas capaz de imitar a dinâmica da remocao de esporos pelas CLPP e simultaneamente ter propriedades ideais como tracador para imagiologia molecular. Testamos sete diferentes formulacoes lipossomicas, tendo a formulacao F demonstrado possuir propriedades fisicoquimicas e radiofarmaceuticas que a tornam o tracador ideal para imagiologia molecular in vivo das CLPP. Os nanorradiolipossomas da formulacao F apos marcacao com 99m Tc-HMPAO foram administrados sob a forma de aerossois a 20 Sus scrofa . Visualizaram-se comunicacoes hilares e interpulmonares nos primeiros 5 minutos apos a inalacao, as cadeias infradiafragmaticas entre os 10 e os 20 minutos, os gânglios da cadeia aortica aos 20 minutos e os da regiao hilar renal aos 30 minutos. Em conclusao, o metodo proposto visualiza os gânglios linfaticos e a rede linfatica pulmonar profunda. A modulacao dos nanorradiolipossomas permite que eles atinjam orgaos ou tecidos especificos, conferindo-lhes importantes potencialidades no âmbito do diagnostico e/ou da terapeutica. Rev Port Pneumol 2009; XV (2): 261-293

Brokerage mechanism proposal for teleradiology studies distribution

The asymmetric distribution of PACS equipment and service providers across countries leads typically to the need to hire third party service professionals outside the institutions where the exams were made. In this paper we present a brokerage mechanism that puts customers and remote providers together in a seamless way. The proposed solution, asserted with a case study for the Portuguese national health system, addresses the problems that now impair the optimal provision of those services, enabling a more agile relationship between buyers and sellers, optimizing administrative work and complying with clinical and legal requirements under discussion in the European Union for the free movement of patients and professional health workers. In this document, the detailed process and technical description of the broker functioning is made, and the main benefits for the participants are also evaluated from a technical and economical point of view. Finally, in the discussion chapter, an assessment of the creation of a spot market for imaging studies is made and the integration with other similar markets is discussed.

NeuronRead, an open source semi-automated tool for morphometric analysis of phase contrast and fluorescence neuronal images

ABSTRACT Neurons are specialized cells of the Central Nervous System whose function is intricately related to the neuritic network they develop to transmit information. Morphological evaluation of this network and other neuronal structures is required to establish relationships between neuronal morphology and function, and may allow monitoring physiological and pathophysiologic alterations. Fluorescence‐based microphotographs are the most widely used in cellular bioimaging, but phase contrast (PhC) microphotographs are easier to obtain, more affordable, and do not require invasive, complicated and disruptive techniques. Despite the various freeware tools available for fluorescence‐based images analysis, few exist that can tackle the more elusive and harder‐to‐analyze PhC images. To surpass this, an interactive semi‐automated image processing workflow was developed to easily extract relevant information (e.g. total neuritic length, average cell body area) from both PhC and fluorescence neuronal images. This workflow, named ‘NeuronRead’, was developed in the form of an ImageJ macro. Its robustness and adaptability were tested and validated on rat cortical primary neurons under control and differentiation inhibitory conditions. Validation included a comparison to manual determinations and to a golden standard freeware tool for fluorescence image analysis. NeuronRead was subsequently applied to PhC images of neurons at distinct differentiation days and exposed or not to DAPT, a pharmacological inhibitor of the &ggr;‐secretase enzyme, which cleaves the well‐known Alzheimers amyloid precursor protein (APP) and the Notch receptor. Data obtained confirms a neuritogenic regulatory role for &ggr;‐secretase products and validates NeuronRead as a time‐ and cost‐effective useful monitoring tool. HighlightsNovel semi‐automatic easy‐to‐use macro for morphological analysis of neuronal cells.The NeuronRead macro can analyze both Phase Contrast and Fluorescence 2D images.NeuronRead extracts morphometric data from neuronal differentiation cell models.NeuronRead is able to detect morphological changes induced by drugs such as DAPT.

Integrated package for interactive analysis and interpretation of nuclear medicine images

This paper describes a software package based on a set of integrated tools intended to be used in nuclear medicine imaging environments. These tools, following a functionally consistent and open architecture, aim to provide an efficient and user-friendly way for handling the analysis and interpretation of nuclear medicine images in a broad range of applications. The Image, Graphics, and Colors tools are the basic building blocks. Besides basic image handling facilities, the Image tool was designed to accomplish both conventional and special purposed processing tasks. Among these, the interactive definition of organ shaped regions of interest, functional imaging (e.g., mean transit time images in ventilatory lung studies) and activity quantitation should be pointed out as the most intensively used facilities. The Graphics tool is used mainly to display and analyze the activity/time curves resulting from parametric related studies. As intensity color coding has gained wide acceptance in nuclear medicine it was thought convenient to implement a Colors tool intended to provide interactive intensity manipulation. The X Window graphics interface system is the basis for the implementation of this set of independent but intercommunicating tools which are intended to run on all UNIX workstations provided with, at least, an 8 bit depth frame buffer.