The invention relates to a measuring device to generate a differential pressure representative of the flow rate of gaseous flow for medical imaging, including: a central body provided with longitudinal channels communicating with an inlet and outlet for the gaseous flow, a casing surrounding the central body, and seals delimiting a first space for measuring an upstream pressure and a second space for measuring a downstream pressure, each of which communicates with at least one of the longitudinal channels, and a third space for warming the central body. The invention also relates to a device to detect the position of a moving area, analysed by medical imaging, of the body of a patient, as well as medical imaging apparatus incorporating such a detection device.
