The invention provides an ultrasound processing unit. A controller (18) of the unit is adapted to receive ultrasound data of an anatomical region, for example of the heart. The controller processes the ultrasound data over a period of time to monitor and detect whether alignment of a particular anatomical feature (34) represented in the data relative to a field of view (36) of the transducer unit is changing over time. In the event that the alignment is changing, the controller generates an output signal for communicating this to a user, allowing a user to be alerted at an early stage to likelihood of misalignment and loss of imaging or measurement capability.
