[CT Scan Angiography In The Pulmonary Embolism's Diagosis At Radiology And Nuclear Medicine Department In Hôpital Du Point "G"]. / Apport De L'Angioscanner Thoracique Dans Le Diagnostic De L'Embolie Pulmonaire Dans Le Service De Radiologie Et De Medecine Nucleaire Du Chu Du Point «G¼.

OBJECTIVE: The aim of this study was to precise the role of thoracic CT angiography in the diagnosis of pulmonary embolism in our practice. PATIENTS AND METHODS: We conduct a prospective eight (8) month study in the radiology department of the Teaching Hospital of Point "G" Seventy seven patients suspected of pulmonary embolism were included. A thoracic CT angiography was performed in emergency after chest X ray for each patient. Pulmonary embolisms were classified according to the Qanadli index. RESULTS: The average age of our patients was 52 years old (23 - 85 years). The age group 55-64 was predominant. The clinical probability was low, medium and high respectively in 8,9%, 28,9% and 62,33%. Chest X ray was suspect of embolism in 92,2% (71/77%), thoracic CT angiography was positive in 58,44% (45/77). Embolism was located in a lobar pulmonary artery in 57,78% and the right side was the most concerned. Among the cardiopulmonary consequences, dilatation of the trunk of the pulmonary artery predominated in 42,22% of cases. According to Qanadli index, the severity of pulmonary embolism was moderate (53;33%), severe (35,56%), and massive (11,11%). CONCLUSION: CT angiography is in our practice, the best choice in the diagnosis of pulmonary embolism. It allows to confirm the diagnosis, and to precise the topography of pulmonary embolism. In addition, this examination makes it possible the severity specification of the affection.

OBJECTIF: Le but de ce travail était de préciser l'apport de l'angioscanner thoracique dans le diagnostic de l'embolie pulmonaire. MATÉRIEL ET MÉTHODES: il s'agissait d'une étude prospective de huit (8) mois dans le service de radiologie et de médecine nucléaire du CHU du point «G¼. Elle a porté sur 77 patients suspects d'embolie pulmonaire et a consisté en la réalisation d'un angioscanner thoracique en urgence précédée par celle d'un cliché du thorax de face. Les embolies pulmonaires ont été classées selon l'index de Qanadli. RÉSULTATS: L'âge moyen de nos patients était de 52 ans avec des extrêmes de 23 ans et 85ans. La tranche d'âge de 55-64 ans était prédominante. Selon le score révisé de Genève, la probabilité clinique était faible dans 8,9% des cas, modérée dans 28,9% des cas et forte dans 62,33% des cas. Une anomalie était notée sur la radiographie du thorax de face dans 92,2% (71/77) des cas. L'angioscanner thoracique a mis en évidence un embole intravasculaire dans 58,44% (45/77). L'embole siégeait dans le tronc d'une artère lobaire dans 57,78% et le côté droit était le plus touché. Parmi les conséquences cardiovasculaires, la dilatation du tronc de l'artère pulmonaire prédominait dans 42,22% des cas. Selon l'index de Qanadli, la gravité de l'embolie pulmonaire était modérée (53,33%), sévère (35,56%) et massive (11,11%). CONCLUSION: l'angioscanner est dans notre contexte le meilleur examen pour le diagnostic de l'embolie pulmonaire. Il nous a permis de faire le diagnostic positif, topographique et de préciser la gravité de l'embolie pulmonaire.

Elimination of ghosting artifacts from wavelength-shifting fiber neutron detectors.

Misassignment of neutron position (ghosting) produces artifacts which have been observed in wavelength-shifting (WLS) fiber detectors developed for time-of-flight (TOF) neutron powder diffraction. In position-sensitive detectors (PSDs) with WLS fiber encoding, thermal and cold neutrons interact with a monolithic (6)LiF/ZnS:Ag scintillator screen, and scintillation photons are generated and transported through the crossed fibers to photomultipliers (PMTs). The neutron position is determined by photon counts in the PMTs within a preset time window. Ghosting occurs when neutrons hit the group boundaries of two neighboring PMTs for x-position multiplexing, which is modeled as resulting from a long travel length (about 3-5 mm) of a small number of scintillation photons. This model is supported by the change observed in aperture images when the threshold number for photon-pulses was adjusted for neutron event determination. When the threshold number of photon-pulses was set above 10 for each PMT, the ghost peaks in the aperture images and TOF spectra of powder diffraction were strongly suppressed or completely eliminated, and the intrinsic background levels of the WLS detectors were significantly reduced. Our result indicates that WLS fiber detector is a promising alternative for (3)He PSDs for neutron scattering.