Assessment of Distal Limbs Fractures With Cone-Beam CT Newtom 5G

ConeBeam scanner (CBCT) is a widely technique used for dental and maxillofacial imaging. Patients can be set up in a sitting or a laying position in the, Newtom 5G CBCT allowing for an analysis of the distal appendicular skeleton. The investigators' hypothesis is that the cone-beam scanner could detect and characterize fractures of the extremities similarly to a multidetector CT (MDCT). 150 patients over 18 years requiring a CT scan for a suspected distal limb fracture or a preoperative assessment will be enrolled. The primary endpointis based on the ability of cone-beam scanner to properly characterize the type of fracture using a classification derived from Maurice E. Müller (AO) classification. Secondary endpoints will concern the depiction of the fracture, the assessment of the soft tissues near the fracture, quality of images, inter and intra-operator reproducibility and tolerance of the patient for the examination. Patients will have a MDCT considered as the reference exam, then a CBCT. Exams will be anonymized and read twice by two trained radiologists with 3-6 week intervals. The inter-observer agreement for the diagnosis of fracture type between the two techniques will be evaluated by a kappa coefficient. The evaluation of diagnostic performance will be achieved by studying the sensitivity, specificity, negative predictive value and positive predictive value, and its likelihood ratio. Kappa test will be performed to evaluate the consistency of the characterization of the fracture and the evaluation of soft tissue near the fracture. A Student t test will be performed for paired data if distributions are normal, a Wilcoxon test if not. To assess patient's tolerance, the percentages of (painful, not painful) will be calculated for each technique and will be compared using the Chi2 test (or Fisher's exact test if the chi can not apply).