This study has four objectives:~Determine the robustness of the placement and measurement algorithms with ultrasound images, obtained with different ultrasound system settings and probe movements.~Verificate and optimize the arterial blood flow model.~Determine the variation in location and size of the arteries and veins in the area around the common carotid artery.~Determine the influence of probe orientation on parameters obtained from ultrasound measurements of the common carotid artery.~Sample size and missing data Due to limited time in the operating room, the measurement protocol is divided into four parts. Per protocol part data of 25 patients is deemed sufficient to be able to answer the above-mentioned objectives, which would result in a total of 100 inclusions. However, the investigators expect to perform more than one measurement protocol per patient, due to which a total of 75 inclusions is needed. Patients of whom the data is qualitatively too low to be used for analysis will be replaced. As such, the investigators make sure to have qualitatively good data of 25 patients per protocol part.
This study is set up to test the robustness of algorithms and models and to optimize them. Furthermore, data are used to investigate the influence of probe orientation on parameters of the common carotid artery.