"Ici la Suisse-Do isch t Schwyz-Switzerland calling!" : la société suisse de radiodiffusion (SSR) au service du rayonnement culturel helvetique (1932-1949)

La dialectique entre radiodiffusion et histoire des relations culturelles internationales est un domaine largement inexploré. L'objectif de cette thèse est d'analyser le rôle de la Société suisse de radiodiffusion (SSR), société privée qui exerce jusqu'en 1983 le monopole sur l'ensemble des stations de radio suisses, dans l'intensification des relations culturelles internationales de la Confédération. Pour examiner cette dimension des activités de la SSR, je me suis prioritairement penchée sur l'étude de la radio internationale helvétique, dénommée alors « Service suisse d'ondes courtes » (SOC). A l'instar de plusieurs organismes similaires à l'étranger, le SOC remplit dès ses débuts une double mission : resserrer les liens avec la diaspora et faire rayonner le pays hors des frontières nationales. Cette recherche met sur le devant de la scène un acteur médiatique aujourd'hui totalement oublié, le Service suisse d'ondes courtes. Par rapport à l'historiographie des radios internationales, elle mêle approche institutionnelle et, dans la mesure des sources disponibles, l'analyse de la programmation. Elle complète aussi l'histoire de la diplomatie culturelle suisse en rappelant la place du service public audiovisuel parmi les institutions chargées de promouvoir le pays à l'étranger. Pour finir, cette étude constitue également un apport à l'histoire des organisations internationales liées à la radiodiffusion (UIR, UIT). L'analyse du volet international des activités de la SSR a permis de dépasser la seule notion de « puissance » qui a été jusqu'à ces dernières années au coeur des ouvrages dévolus aux radios internationales. L'objectif poursuivi par la SSR ne réside pas tellement dans la diplomatie d'influence (l'exercice d'un « soft power »), qui tend à imposer ses valeurs et un mode de vie, mais plutôt dans la volonté de faire comprendre et reconnaître la culture politique de la Suisse dans le but de renforcer et pérenniser la place de celle-ci dans le concert des nations. Dans cette perspective, la culture devient un moyen utilisé pour transmettre à l'étranger une représentation valorisante du pays, une image de marque (une forme de « Nation Branding » avant l'heure) également utile au secteur touristique et à l'industrie d'exportation. Le Service suisse d'ondes courtes fait ainsi avant tout des relations publiques, un avant-goût de ce que les Américains appelleront dans les années 1960 la « public diplomacy »

Cerebral perfusion CT: Current state of the art : P44

Purpose: The aim of this educational poster is to introduce the technical principles of cerebral perfusion CT and to provide examples of its clinical applications and potential limitations in the everyday emergency practice. Methods and materials: Cerebral perfusion CT is a well established investigatory tool for many vascular and parenchymal brain dysfunctions. CT perfusion maps allow a semiquantitative assessment of cerebral perfusion. Results: Currently, cerebral perfusion CT has a pivotal role in differentiating reversible from irreversible ischemic parenchymal insult besides its integral role in grading vasospasm after subarachnoid hemorrhage. Furthermore, cerebral perfusion CT can be coupled to acetazolamide administration in order to assess the cerebrovascular reserve capacity before performing extra-/intra-cranial bypass surgery in patients with cerebral vascular insufficiency. Cerebral perfusion CT can also identify diffuse abnormalities of cerebral perfusion in children with traumatic brain injury showing a low initial GCS in order to predict the final outcome regarding the late occurrence of irreversible parenchymal damage. Cerebral Perfusion CT is also able to detect focal parenchymal perfusion abnormalities in acute epileptic seizures. Conclusion: Cerebral perfusion CT can be integrated in the management of many vascular, traumatic and functional disorders of the brain.

Is MDCT enough reliable for the evaluation of acute colitis including the underlying etiology? : correlation with colonoscopy and pathology : P2

Purpose: 1. To assess the diagnostic value of MDCT for acute colitis of various origin confirmed by colonoscopy and histology. 2. To evaluate the accuracy of MDCT of making the correct differential diagnosis. Methods and materials: The electronic hospital database from January 2006 to August 2008 revealed 351 patients with acute colitis of any origin wdetected by colonoscopy. In 85 out of these patients MDCT had been simultaneously performed (delay 3.1 days). Two radiologists jointly reviewed their corresponding CT features without knowledge of pathology and correlated them with the final histological diagnosis. Results: Eighty patients were finally included (46 women, mean age 63.4). Colitis was of ischemic (n = 35, 44%) or infectious (n = 15, 19%) origin. 18 patients (23%) had acute ulcerative colitis or Crohn's disease, in 10 patients (12%) another inflammatory cause and in two patients (2%) post radiation colitis was proven. MDCT was positive in 63 patients (78.9%). In 11 out of the 17 negative MDCT, the examination had been performed without large bowel distention. Ischemic colitis was responsible for 47.1% of the negative MDCT. Correct differential diagnosis was made in 32 (50.7%) out of the 63 positive MDCT. Among the different etiologies, the ischemic colitis was the most often misdiagnosed cause (n = 17, 58.6%). Conclusion: Large bowel distension is mandatory for reliable MDCT detection of acute colitis of any origin. Among the different aetiologies the ischemic cause is the most often associated with false negative MDCT findings and, in case of positive features, the most difficult to recognize as such.

Intraobserver and interobserver variability of ascending aorta diameter measurements as assessed by ECG-gated MDCT : automatic versus manual measurements : P15

Purpose: Revolutionary endovascular treatments are on the verge of being available for management of ascending aortic diseases. Morphometric measurements of the ascending aorta have already been done with ECG-gated MDCT to help such therapeutic development. However the reliability of these measurements remains unknown. The objective of this work was to compare the intraobserver and interobserver variability of CAD (computer aided diagnosis) versus manual measurements in the ascending aorta. Methods and materials: Twenty-six consecutive patients referred for ECG-gated CT thoracic angiography (64-row CT scanner) were evaluated. Measurements of the maximum and minimum ascending aorta diameters at mid-distance between the brachiocephalic artery and the aortic valve were obtained automatically with a commercially available CAD and manually by two observers separately. Both observers repeated the measurements during a different session at least one month after the first measurements. Intraclass coefficients as well the Bland and Altman method were used for comparison between measurements. Two-paired t-test was used to determine the significance of intraobserver and interobserver differences (alpha = 0.05). Results: There is a significant difference between CAD and manual measurements in the maximum diameter (p = 0.004) for the first observer, whereas the difference was significant for minimum diameter between the second observer and the CAD (p <0.001). Interobserver variability showed a weak agreement when measurements were done manually. Intraobserver variability was lower with the CAD compared to the manual measurements (limits of variability: from -0.7 to 0.9 mm for the former and from -1.2 to 1.3 mm for the latter). Conclusion: In order to improve reproductibility of measurements whenever needed, pre- and post-therapeutic management of the ascending aorta may benefit from follow-up done by a unique observer with the help of CAD.

The different types of internal hernia after laparoscopic Roux-En-Y gastric by-bass for morbid obesity : MDCT features : P5

Purpose: 1. To provide an overview of the different types of internal hernia (IH) occurring after laparoscopic Roux-en-Y gastric bypass (LRYGBP) performed for morbid obesity. 2. To describe the correspondent MDCT features in relation with the underlying anatomical landmarks in order to differentiate their localisation and to direct the surgeon during following laparoscopic closure of mesenteric defects. Methods and materials: LRYGBP performed for morbid obesity is associated with less perioperative complications, shorter hospital stay and a more rapid recovery compared with the open surgical procedure. However, a relatively high incidence of IH is seen that may be due to the laparoscopic approach, but also caused by rapid weight loss with consecutive loosening of the mesenteric sutures. Results: After briefly reviewing the surgical procedure of LRYGBP (ante- versus retrocolic) we describe the exact anatomical landmarks of the different types of IH occurring at any time after operation: They are caused by surgical defects either at the level of the transverse colon mesentery, at the Petersen's space, which represents an opening between the mesocolon and jejunal mesentery, or at the enteroenterostomy site. Typical MDCT features of each IH type in axial and coronal plane as well as targeted vascular reconstructions are demonstrated. Conclusion: Exact knowledge about underlying pathophysiology and anatomical landmarks is essential for distinguishing the different types of IH occurring after LRYGBP on MDCT, since radiological features are difficult to recognize and may even overlap. The radiologist should be aware of the potential anatomic sites to ensure subsequent straightforward laparoscopic exploration.

High-field (3T) magnetic resonance defecography with functional assessment of the evacuation phase : a pictorial essay : P10

Purpose: Dynamic high-field magnetic resonance (MR) defecography including the evacuation phase is a promising tool for the assessment of functional pelvic disorders, nowadays seen with increasing frequency in elderly women in particular. Learning objectives: 1. To describe the adequate technique of dynamic high-field MRI (3T) in assessing pelvic floor disorders. 2. To provide an overview of the most common pathologies occurring during the evacuation phase, especially in comparison with results of conventional defecography. Methods and materials: After description of the ideal technical parameters of MR defecography performed in supine position after gel rectal filling with a 3 Tesla unit and including the evacuation phase we stress the importance of using a standardized evaluation system for the exact assessment of pelvic floor pathophysiology. Results: The typical pelvic floor disorders occurring before and/or during the evacuation phase, such as sphincter insufficiency, vaginal vault and/or uterine prolapse, cystourethrocele, peritoneo-/ entero-/ sigmoïdocele or rectal prolapse, are demonstrated. The difference between the terms "pelvic floor descent" and "pelvic floor relaxation" are pictorially outlined. MR results are compared with these of conventional defecography. Conclusion: Exact knowledge about the correct technique including the evacuation phase and the use of a standardized evaluation system in assessing pelvic floor disorders by dynamic high-field MRI is mandatory for accurate and reproducible diagnosis.