Ultrasound Transducer Index Mark
©Walter Rasmussen, R.D.C.S.
All ultrasound transducers have an index mark consisting of a slight prominence, sometimes with an led light (as pictured), that marks the edge of the imaging plane. During the course of a standard echocardiography examination, the transducer is manipulated so that the index mark is kept on either the most cephalic or leftward side of the anatomy for each view.
The index mark location is shown as a small dot or symbol next to the peak of the right side of the sector image.
Since the sector image can be flipped both horizontally and vertically either by accident or intention, the index mark on the screen will follow any such change in image orientation and is useful for making certain that the scanner is set-up properly for echocardiography with the index to the right side on the monitor.
An index mark that is reversed horizontally.