Low-dose CT Angiography in the Detection of Acute Pulmonary Embolism: Validation in an Obese Population

The study is monocentric, realised in University Hospital of Clermont-Ferrand, France, using the CT GE Revolution dedicated to the emergency service. For each patient with suspicion of pulmonary embolism, regarding the inclusion and exclusion criteria (explained later), investigators realise the same protocol. Patients are divided into 2 groups of weight : \<30 kg/m2, \> 30 kg/m2. There is no change in the management of patients, who benefit from an angioscan for pulmonary embolism, with an optimized protocol for patients under 100 kg and validated by the literature (Megyeri et al. , 2015) for patients over 100 kilos, with no loss of diagnostic chance and with an improvement over the irradiation compared to the usual protocols used (over-irradiation in the obese, up to 140 kV). Concerning the CT protocol, a voltage of 100 kV is applied (irradiation 40% lower than a 120 kV test), with a modulation of the intensity of the current according to the Z axis and use of different levels of iterative reconstructions on images obtained to improve diagnostic performance. Regarding the injection protocol, the same product with high concentration of iodine is injected to all patients (IOMERON 400), with a quantity relative to the weight of 1 mL / kg of patient weight, a maximum of 90 mL, a rate of 4 mL / s and rinsing with 30 mL of saline solution at 3 mL / sec The session physician first carries out diagnostic work by searching for pulmonary embolism or an alternative diagnosis to explain the symptoms. Secondly, the research work is carried out and the analyzed data with evaluation of the objective diagnostic quality, placing regions of circular interest or ROI (for regions of interest), in the pulmonary arteries, up to the sub-segmental branches. The subjective quality is evaluated by two double-blind readers by a subjective quality scale. The different elements are then compared according to two different groups of weights and BMIs. Intermediate statistical analyzes are planned for all 30 patients. The study started on March 21st, for an estimated duration of 6 months initially. 65