A medical imaging apparatus and a device to detect the position of a moving part of the body of a patient. The detection device includes a management module including electronic and electric components including a differential pressure sensor linked to a measuring device that generates a differential pressure representative of the respiration flow rate of the patient, the management module being organized so as to perform at least: one acquisition and processing of the data produced by the differential pressure sensor for the generation of data representative of the respiratory volume and for the generation of an outgoing digital synchronization signal the reception of an incoming digital synchronization signal the generation of an outgoing digital signal of data representative of the respiratory volume in line with one of the two synchronization signals.
