Real time imaging means continua monitoring of image. 

This is a broad definition, in medical device real Time Imaging has a deeper meaning of: vast data being processed, grabbed and framed, each frame is processed with filters and all this with very low latency (usually less than a frame). The output is an isolated HDMI with isolated HI-RES touch screen, and all is recorded to internal storage (real time).

Typical structure of medical device real time imaging block diagram: