Esta pesquisa foi realizada com o objetivo de identificar as inclinações dentárias vestíbulo-linguais dos dentes superiores e inferiores e as espessuras ósseas alveolares maxilo-mandibulares em indivíduos com deformidade dentofacial de classe III e comparar com indivíduos com oclusão normal para verificar, a partir da correlação entre estas duas variáveis, se o processo natural de remodelação óssea provê uniformidade da espessura óssea, ou se a mesma varia em torno das raízes em função da inclinação dentária. A amostra constituiu-se de 70 indivíduos adultos, 35 com face equilibrada e oclusão normal, e 35 com deformidade dentofacial de classe III, não tratados ortodonticamente e com saúde periodontal. A partir de imagens tridimensionais geradas por exames de tomografia computadorizada de feixe cônico, foram mensuradas as inclinações vestíbulo-linguais de todos elementos dentários e as espessuras ósseas alveolares maxilo-mandibulares em três alturas diferentes (3, 6 e 8 milímetros) a partir da junção amelocementária por meio do programa Dolphin 3D®. O erro do método foi avaliado por meio das correlações intraclasses e pela fórmula de Dahlberg. O teste de Correlação de Pearson foi utilizado para verificar a relação entre inclinação dentária e espessura óssea. As espessuras médias nas alturas de 3 e 8 milímetros e as inclinações foram comparadas entre os dois grupos com uso de testes t-Student. As medidas apresentaram alta reprodutibilidade. A região alveolar correspondente ao canino superior apresentou-se mais delgada e a palatina dos incisivos centrais superiores mais espessa. Na mandíbula, as maiores medidas de espessura óssea alveolar foram observadas na região disto-vestibular do segundo molar inferior. Os dados observados mostram valores menores das medidas avaliadas na altura de 3 mm da junção amelocementária, para ambos grupos estudados. Nos indivíduos com oclusão normal, as maiores inclinações foram observadas nos incisivos e estes valores foram diminuindo progressivamente em direção posterior. Nos indivíduos com deformidades dentofaciais de classe III, as maiores inclinações foram observadas nos incisivos superiores e nos caninos inferiores e as menores inclinações foram observadas nas raízes vestibulares dos segundos molares inferiores. Em relação à comparação entre os grupos estudados, os segundos prémolares, incisivos laterais e os incisivos centrais superiores apresentaram maiores inclinações e os segundos molares, primeiros pré-molares e incisivos laterais e centrais inferiores apresentaram-se menos inclinados nos indivíduos classe III. Todas as espessuras médias em 3 mm foram estatisticamente menores nos indivíduos classe III em relação aos indivíduos com oclusão normal, e a maioria das espessuras avaliadas em 8 mm apresentou menor valor nos indivíduos classe III. Além disso, nos indivíduos classe III, foram encontradas mais correlações estatisticamente significativas positivas entre inclinação e espessura nos dentes inferiores, enquanto que nos indivíduos com oclusão normal, foram encontradas poucas correlações estatisticamente significativas entre estas duas variáveis. / This research was conducted with the purposes of identifying the buccolingual inclinations of the upper and lower teeth and the maxillo-mandibular alveolar bone thickness in patients with Class III dentofacial deformities and of comparing these measurements with those from individuals with normal occlusions to verify, based on the correlation between these two variables, whether the natural process of bone remodeling provides uniformity of bone thickness or whether it varies around the roots due to tooth inclination. The sample consisted of 70 periodontally healthy adults, 35 with balanced faces and normal occlusions and 35 with Class III dentofacial deformities, with no history of previous orthodontic treatment. The buccolingual inclinations of all of the teeth and the maxillo-mandibular alveolar bone thickness were measured at three different heights (3, 6 and 8 mm) from the cementoenamel junction, using Dolphin® 3D software, from three-dimensional images generated by cone beam computed tomography. The error of the method was evaluated by means of intraclass correlations and Dahlberg\'s formula. Pearsons correlation test was used to verify the relationship between tooth inclination and bone thickness. The average thickness at 3 and 8 millimeters apical from cementoenamel junction, and the tooth inclinations were compared between the two groups using Student\'s t-test. The measures showed high reproducibility. The alveolar region corresponding to the upper cuspids appeared thinner, and the palatal area of the maxillary central incisors appeared thicker. In the mandible, the greatest measures of alveolar bone thickness were observed in the distobuccal region of the second molar. The data clearly showed lower values of the measurements evaluated at 3 mm from the cementoenamel junction for both groups. In individuals with normal occlusions, greater tooth inclinations were observed on the incisors, and these values decreased gradually toward the posterior region. In subjects with Class III dentofacial deformities, greater tooth inclinations were observed in the upper incisors and lower cuspids, and smaller tooth inclinations were observed on the buccal roots of the lower second molars. Regarding comparison between the groups, the second premolars, maxillary lateral and central incisors showed greater inclinations, and the second molars, first premolars and lower lateral and central incisors were less inclined in individuals with Class III deformities. All of the average values regarding alveolar bone thickness at 3 mm from cementoenamel junction were statistically lower in Class III subjects, compared to subjects with normal occlusions, and the majority of the evaluated values at 8 mm showed smaller values in individuals with Class III deformities. In addition, in individuals with Class III deformities, more positive statistically significant correlations were found between inclination and thickness in the lower teeth, whereas in subjects with normal occlusions, few statistically significant correlations were found between these two variables.

Breast cancer is a major disease in women worldwide with a high rate of mortality, second only to lung cancer. Hence, there is considerable interest in developing non-invasive breast cancer detection methods with the aim of identifying breast cancer at an early stage, when it is most treatable. Electrical impedance mammography (EIM) is a relatively new medical imaging method for breast cancer detection. It is a safe, painless, non-invasive, non-ionizing imaging modality, which visualizes the internal conductivity distribution of the breast under investigation. Currently some EIM systems are in clinical trials but not commercialized, as there are still many challenges with sensitivity, spatial resolution and detectability. The research in this thesis aims to enhance and optimize EIM systems in order to address the current challenges. An enhanced image reconstruction algorithm using the duo-mesh method is developed. Both in simulations and real cases of phantoms and patients, the enhanced algorithm has proven more accurate and sensitive than the former algorithm and effective in improving vertical resolution for the EIM system with a planar electrode array. To evaluate the performance of the EIM system and the image reconstruction algorithms, an image processing based error analysis method is developed, which can provide an intuitive and accurate method to evaluate the reconstructed image and outline the shape of the object of interest. Two novel EIM systems are studied, which aim to improve the spatial resolution and the detectability of a tumour deep in the breast volume. These are: rotary planar-electrode-array EIM (RPEIM) system and combined electrode array EIM (CEIM) system. The RPEIM system permits the planar electrode array to rotate in the horizontal plane, which can dramatically increase the number of independent measurements, hence improving the spatial resolution. To support the rotation of the planner electrode array, a synchronous mesh method is developed. The CEIM system has a planar electrode array and a ring electrode array operated independently or together. It has three operational modes. This design provides enhanced detectability of a tumour deep within the tissue, as required for a large volume breast. The studies of the RPEIM system and the CEIM system are based on close-to-realistic digital breast phantoms, which comprise of skin, nipple, ducts, acini, fat and tumour. This approach makes simulations very close to a clinical trial of the technology.

In the medical field, the detection and diagnosis of diseases continue to improve. Developments in diagnostic techniques have helped to improve treatment in the early stages and avoid many risks to patients. One relatively new diagnostic technique is optical coherence tomography (OCT), which is used in many medical applications to perform internal microstructure imaging of the human body at high resolution (typically 10 micro metre), at high speed and in real time. OCT is non-invasive and can be used as a contact or non-contact technique to obtain an image. In medicine, there are many applications that involve OCT, such as in ophthalmology, gastroenterology, cardiology and oncology. This work demonstrates the design, development and implementation of a high resolution swept laser OCT system for the imaging and diagnosis of tissues in laboratory and clinical experiments. It reports an investigation to measure the thickness of the peritoneal membrane and the use of optical imaging contrast agents such as gold nanorods. There is also an account of the design of an endoscope-catheter fast scanning OCT system for biomedical studies of the gastrointestinal tract and gynaecological areas. These results were achieved by using a swept tuneable laser source with a very high tuning speed of 16 kHz over a wide range of wavelengths: 1260 nm to 1390 nm. The laser sweeps across 110 nm at a 16 kHz repetition rate. The real axial line speed is limited by the source that is used in the OCT system. The axial resolution of the system is 7 µm and its transverse resolution is 15 µm. The bandwidth of the source is up to DeltaGamma = 110 nm, centred at Gamma0 = 1325 nm, and the coherent length is 7 µm. On the sample arm of the interferometer, the swept laser OCT technique is combined with an optical probe and endoscope in order to develop a novel diagnostic imaging device to visualize tissue in vivo for animal and human experimental trials.

The thesis discusses various electrode models and finite element analysis methods for Electrical Impedance Tomography (EIT) systems. EIT is a technique for determining the distribution of the conductivity or admittivity in a volume by injecting electrical currents into the volume and measuring the corresponding potentials on the surface of the volume. Various electrode models were investigated for operating EIT systems at higher frequencies in the beta-dispersion band. Research has shown that EIT is potentially capable to distinguish malignant and benign tumours in this frequency band. My study concludes that instrumental effects of the electrodes and full Maxwell effects of EIT systems are the major issues, and they have to be addressed when the operating frequency increases. In the thesis, I proposed 1) an Instrumental Electrode Model (IEM) for the quasi-static EIT formula, based on the analysis of the hardware structures attached to electrodes; 2) a Complete Electrode Model based on Impedance Boundary Conditions (CEM-IBC) that introduces the contact impedances into the full Maxwell EIT formula; 3) a Transmission line Port Model (TPM) for electrode pairs with the instrumental effects, the contact impedance, and the full Maxwell effects considered for EIT systems. Circuit analysis, Partial Differential Equations (PDE) analysis, numerical analysis and finite element methods were used to develop the models. The results obtained by the proposed models are compared with widely used Commercial PDE solvers. This thesis addresses the two major problems (instrumental effects of the electrodes and full Maxwell effects of EIT systems) with the proposed advanced electrode models. Numerical experiments show that the proposed models are more accurate in the high frequency range of EIT systems. The proposed electrode models can be also applicable to inverse problems, and the results show promising. Simple hardware circuits for verifying the results experimentally have been also designed.

The research concentrates on the design, development and calibration of a high performance Electrical Impedance Mammography (EIM) system for early detection of breast cancer at the macro and micro scale (at an early stage applicable for different breast sizes and shapes). The enhancement of the Electrical Impedance Tomography (EIT) system focuses on developing electrical and electronic instrumentations and improving the current source topologies to make them operate at multiple frequencies for the purpose of measuring permittivity and conductivity of different breast tissues. The calibration, assessment systems have employed current calibration in the EIT to evaluate the impedance distribution. This facilitates the acquisition of accurate impedance images to enable images of the internal structure of the breast to be constructed. A constraint on EIT systems is that the current injection system suffers from the effects of stray capacitance having a major impact on the hardware subsystem as the EIT is an ill-posed inverse problem which depends on the noise level in EIT measured data and regularization parameter in the reconstruction algorithm. This research aims are to prevent this problem by using a capacitance cancellation method based on a General Impedance Converter (GIC) implemented by operation of a second generation of current conveyor called OCCII-GIC and calibration methods to facilitate operation in the high frequency range. An EIT system based on a planar 85-electrode channel and using a Microcontroller unit (MCU) for addressing control between 85 electrodes and implementing calibration methods has been constructed. In EIT systems, assessment, validation of the performance and calibration of systematic errors in the electrical field generated inside of the interrogated volume is important. Evaluation of the EIT system will be assessed using a realistic electronic phantom (E-phantom). This enables the evaluation of the different conductivity values of the tissue, which has been created and evaluated based on the RSC circuit model for the different electrical conductivities and electrical impedivities in breast tissue.

A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in partial fulfilment of the requirements for the degree of Master of Medicine in Diagnostic Radiology Johannesburg, 2014 / INTRODUCTION South Africa presents a complex scenario with regard to patients consenting for medical procedures, because of the differing profiles of the population and the health care workers who perform the consenting procedures. AIM To evaluate consenting practice for CT scanning, within the South African tertiary referral setting and to determine if there are any associations between patient demographic profile and the level of understanding with the adequacy of consent. METHOD A prospective survey regarding consenting practices for CT scanning was performed in a form of an interview questionnaire in patients presenting to Chris Hani Baragwanath Academic and Charlotte Maxeke Johannesburg Academic hospitals. Determination of any associations between patient age, racial group, language and education was made with the level of understanding and adequacy of consent. RESULTS The survey was conducted on 117 patients; 86 from Charlotte Maxeke Johannesburg Academic Hospital and 31 from Chris Hani Baragwanath Academic Hospital. We found no significant association between gender and age category (p=0.11), racial group (p=0.17), education (p=0.26), home language (p=0.21) or residential area type (p=0.70). vi There was a significant, weak, association between age category and education (p=0.043; Cramer’s V=0.29). There was a significant, moderate association between the understanding of the language of consent and the home language of the patients (p=0.0013; phi coefficient=0.43). There was also some association between education and age. Just over 50% of patients felt that they had been given enough information and had had an opportunity to ask questions and only 33% had been offered an alternative to the CT scan. There was a significant difference in the mean adequacy of consent score with regards to racial group (p<0.0001), home language (p=0.0073), residential area type (p<0.0001) and level of education (p<0.0001). CONCLUSION Language differences between patients and personnel performing the consent procedure proved to be a major barrier in offering adequate consenting for CT Scans.

Introduction: Increasing the imaging demand in the dental field has lead to a dramatic increase in the number of CBCT machines in the U.S. market with a variety of new models and features, as well as different radiation exposures. These differences in exposure among the different CBCT machines and the potential for radiation accumulation over a life time are major concerns for aiming for a reduction in patients’ radiation exposure. Most of the studies have aimed to measure the radiation dose in different CBCT units with different field of views. Up to date, few studies have aimed to measure the radiation dose in different CBCT devices with similar fields of view. The aim of the study was to compare the dosimetry levels with relatively small FOV in different scan protocols in two CBCT units. Materials and methods: A 16-cm diameter PMMA phantom with 10-cm pencil ionization chamber were used to measure the radiation exposure from two CBCT devices: i-CAT FLX and CS9000. A smallest FOV in both CBCT (8 x 8 cm in the i-CAT FLX and 5 x 3.7 cm in the CS9000) was selected at different scan protocols. The scan settings included in the i-CAT FLX HD (120 kVp; 5 mA; 7.4 sec; 0.125, 0.250, 0.200 mm voxel sizes; 360° rotation) Quick HD (120 kVp; 5 mA; 4.1 sec; 0.200, 0.250 mm voxel sizes; 180° rotation), Quick+ (90 kVp; 3 mA; 2 sec; 0.300, 0.400 mm voxel sizes; 180° rotation) , Quick (120 kVp; 5 mA; 2 sec; 0.300, 0.400 mm voxel sizes; 180° rotation), and standard scans (120 kVp; 5 mA; 3.7 sec; 0.300, 0.400 mm voxel sizes; 360° rotation). In the CS9000 scan settings included voxel sizes (CS9000: 0.076 mm, 0.100 mm, and 0.200 mm), 80 kVp, 10 mA, 10.8 sec, and 360° rotation. The phantom was exposed three times at the same position to calculate the average measurement of dose by the ionization chamber. All the radiation exposure doses were read by one examiner. Results: The radiation exposure of the phantom slots in different resolutions and scan protocols in the both CBCT units ranged from 4.31 to 60.73 mR. There were statistically significant differences in radiation value between i-CAT FLX and CS9000 due to voxel size (P < 0.001). Each voxel size was significantly different from the other in both scanners, except between CS9000 0.076 and HD 0.125; CS9000 0.200 and HD 0.125; and CS9000 0.100 and HD 0.200. Also, there were no statistically significant differences between the voxel size within the same scan protocols in the i-CAT FLX, especially the Quick HD, Quick+, Quick, and Standard scans. Conclusion: The selection of x-ray parameters (mainly scan time), voxel size, and rotation angle have a significant radiation expsoure reduction in both the i-CAT FLX and CS9000 units and hence should be appropriately selected to minimize the radiation dose.

With increasing miniaturization in industry and medical technology, non-destructive testing techniques are an area of everincreasing importance. In this framework, X-ray microscopy offers an efficient tool for the analysis, understanding and quality assurance of microscopic species, in particular as it allows reconstructing three-dimensional data sets of the whole sample’s volumevia computed tomography (CT). The following thesis describes the conceptualization, design, construction and characterization of a compact laboratory-based X-ray microscope in the hard X-ray regime around 9 keV, corresponding to a wavelength of 0.134 nm. Hereby, the main focus is on the optimization of resolution and contrast at relatively short exposure times. For this, a novel liquid-metal-jet anode source is the basis. Such only recently commercially available X-ray source reaches a higher brightness than other conventional laboratory sources, i.e. the number of emitted photons (X-ray quanta) per area and solid angle is exceptionally high. This is important in order to reach low exposure times. The reason for such high brightness is the usage of the rapidly renewing anode out of liquid metal which enables an effective dissipation of heat, normally limiting the creation of high intensities on a small area. In order to cover a broad range of different samples, the microscope can be operated in two modes. In the “micro-CT mode”, small pixels are realized with a crystal-scintillator and an optical microscope via shadow projection geometry. Therefore, the resolution is limited by the emitted wavelength of the scintillator, as well as the blurring of the screen. However, samples in the millimeter range can be scanned routinely with low exposure times. Additionally, this mode is optimized with respect to in-line phase contrast, where edges of an object are enhanced and thus better visible. In the second “nano-CT mode”, a higher resolution can be reached via X-ray lenses. However, their production process is due to the physical properties of the hard X-ray range - namely high absorption and low diffraction - extremely difficult, leading typically to low performances. In combination with a low brightness, this leads to long exposure times and high requirements in terms of stability, which is one of the key problems of laboratory-based X-ray microscopy. With the here-developed setup and the high brightness of its source, structures down to 150 nm are resolved at moderate exposure times (several minutes per image) and nano-CTs can be obtained. / Mit zunehmender Miniaturisierung in Industrie und Medizintechnik werden zerstörungsfreie Prüfverfahren immer wichtiger. In diesem Umfeld bietet Röntgenmikroskopie ein effizientes Instrument zu Analyse, Verständnis und Qualitätssicherung mikroskopischer Proben, insbesondere da sie im Rahmen der Computer-Tomografie (CT) die Aufnahme dreidimensionaler Datensätze des gesamten Probenvolumens ermöglicht. Die vorliegende Arbeit befasst sich mit Konzeption, Design, Aufbau und Charakterisierung eines kompakten Labor-Röntgenmikroskops im harten Röntgenbereich bei 9 keV, bzw. einer Wellenlänge von 0.134 nm. Im Fokus liegt dabei die Optimierung von Auflösung und Kontrast bei möglichst kurzen Belichtungszeiten. Hier für bildet die Basis eine neuartige Flüssig-Metall- Anoden Röntgenquelle. Solche erst seit kurzem kommerziell verfügbare Quellen erreichen eine höhere Brillianz als konventionelle Laborquellen, d.h. dass die Anzahl der emittierten Photonen (Röntgenquanten) pro Fläche und Raumwinkel außergewöhnlich hoch ist. Dies ist ein entscheidender Faktor, um nötige Belichtungszeiten zu verringern. Der Grund für die hohe Brillianz ist die Verwendung einer sich sehr schnell erneuernden Anode aus flüssigem Metall. Diese ermöglicht die effektive Abfuhr von Wärme, welche normalerweise die Erzeugung von höheren Intensitäten auf kleinerer Fläche limitiert. Um ein möglichst großes Spektrum an Proben abzubilden, kann das Mikroskop in zwei Modi betrieben werden. Im ”Mikro-CT Modus“ werden kleine Pixel mit Hilfe eines Kristall-Leuchtschirms und einem Lichtmikroskop über das Schattenwurfprinzip erreicht, weswegen dessen Auflösung durch die Wellenlänge des emittierten Lichts und die Unschärfe des Schirms beschränkt ist. Dafür können Proben im Millimeterbereich bei geringen Belichtungszeiten standardmäßig aufgenommen werden. Zudem wurde dieser Modus auf inline Phasen-Kontrast optimiert, bei welchem die Kanten eines Objekts durch Interferenz überhöht dargestellt werden und somit besser sichtbar sind. Im zweiten ”Nano-CT Modus“ kann eine erhöhte Auflösung mit Hilfe von Röntgenlinsen erreicht werden. Deren Herstellung ist aber aufgrund der physikalische Eigenschaften im harten Röntgenbereichs - nämlich starke Absorption und schwache Brechung - technisch extrem schwierig und meist mit einer sehr geringe optischen “Leistung” verbunden. Dies führt in Kombination mit einer geringen Brillianz zu sehr langen Belichtungszeiten und hohen Anforderungen an die Stabilität, was ein Kernproblem der auf Laborquellen basierenden Röntgenmikroskope darstellt. Mit der hier entwickelten Anlage können durch die hohe Brillianz der verwendeten Quelle bei moderaten Belichtungszeiten (wenige Minuten pro Bild) Strukturen der Größe 150 nm voneinander getrennt, sowie Nano-CTs aufgenommen werden.

La tomographie et ses algorithmes associés sont désormais bien connus dans le domaine des rayons X. En revanche tous ces outils s’appuient sur une modélisation qui diffère de celle qui pourrait être envisagée dans le domaine des ondes Térahertz (THz). On retrouve, dans l’état de l’art, des modèles de propagation de l’onde THz au sein d’un objet. Ces modèles génèrent une onde THz qui est soit éloigné d’une vérité terrain, soit d’une complexité algorithmique trop élevée pour être utilisée au sein d’une reconstruction tomographique dans des temps de calcul acceptables. Un des objectifs de ce travail de thèse est donc d’obtenir un modèle de propagation de l’onde THz permettant une meilleure modélisation du processus d’acquisition et pouvant être calculé dans des temps relativement courts. Lors de la mesure d’une projection d’un objet, le phénomène d’absorption n’est pas le seul phénomène responsable de l’atténuation de l’onde THz. Les phénomènes de réfraction et de réflexion sont aussi responsables d’une atténuation de l’onde THz mesurée. Lors d’une reconstruction tomographique THz, si ces phénomènes ne sont pas pris en compte, l’algorithme attribue cette atténuation au phénomène d’absorption. Cela se traduit par une reconstruction des coefficients d’absorption de l’objet éloignée de leur valeur réelle. Sous l’effet de ces phénomènes, le problème de la reconstruction tomographique THz est non linéaire. Cela empêche ainsi l’utilisation directe des méthodes de reconstruction classiques puisque ces méthodes impliquent que la relation liant un objet à ses projections soit linéaire. / Tomography and its associated algorithms are now well known in the field of X-rays. On the other hand, all these tools are based on a modeling that differs from which could be envisaged in the field of Terahertz (THz) waves. We find, in the state of the art, models of propagation of the THz wave within an object. These models generate a THz wave that is either far from a ground truth, or of an algorithmic complexity that is too high to be used within a tomographic reconstruction in acceptable computing times. One of the objectives of this thesis work is therefore to obtain a propagation model of the THz wave allowing better modeling of the acquisition process and which can be calculated in relatively short times. When measuring the projection of an object, the absorption phenomenon is not the only phenomenon responsible for the attenuation of the THz wave. The phenomena of refraction and reflection are also responsible for attenuation of the measured THz wave. During a THz tomographic reconstruction, if these phenomena are not taken into account, the algorithm attributes this attenuation to the absorption phenomenon. This results in a reconstruction of the absorption coefficients of the object far from their real value. Under the effect of these phenomena, the problem of THz tomographic reconstruction is non-linear. This prevents the direct use of classical reconstruction methods since these methods imply that the relationship between an object and its projections is linear.

Pulmonary embolism (PE) is a severe frequent disease with lack of specific symptoms and represents a major diagnostic challenge. In the past few years, single-slice spiral CT angiography has gained acceptance as a minimally invasive method of evaluating patients with suspicion of PE. The main limitation of single-slice spiral CT resides in the poor detection of subsegmental or more distal PE. This limited detection is not explained by an insufficient vascular distension during spiral CT acquisition but probably by an insufficient spatial resolution. Moreover, in some situations spiral CT is penalized by pulmonary angiography which is an imperfect gold standard. Today Multislice CT can acquire 2 up to 64 slices in a single rotation with isotropic resolution. This technique can cover the entire chest in 1-mm slice thickness or less, in one short breath-hold and allows a better analysis of peripheral pulmonary arteries with a better depiction of sub-segmental and peripheral clots. It also reduces or eliminates artefacts produced by patient movement and decreases the x-ray tube heating that can constrain singleslice scanning parameters. Acquisition of the lower extremities can be performed after chest CT, allowing detection of deep vein thrombosis and one stop shopping of the venous thromboembolic disease. The diagnostic accuracy of multislice CT is probably similar or superior to pulmonary angiography with an inferior delivered radiation dose, a better detection of alternative diagnoses and a continuous decrease of contrast medium injected. Last refinements in CT technology opens new frontiers for a functional approach of PE and predict its prognosis. For all the above-mentioned reasons, it seems obvious that multislice CT will definitively replace pulmonary angiography for diagnostic purposes and will represent a superb tool to better understand the physiopathology of this frequent and potentially life-threatening disorder.