Apparatus and methods are described for imaging a portion of a body of a subject that undergoes a motion cycle. A plurality of image frames of the portion are acquired. The image frames are enhanced with respect to a first given feature of the image frames, by (a) image tracking the image frames with respect to the first given feature, (b) identifying a second given feature in each of the image frames, and (c) in response to the identifying, reducing visibility of the second given feature in the image frames. The image frames that (a) have been image tracked with respect to the first given feature, and (b) have had reduced therein the visibility of the second given feature, are displayed as a stream of image frames. Other embodiments are also described.