(1) Mechanically rotating intravascular echo element

The following picture is a schematic of IVUS catheter with rotating element within a catheter.  This catheter has a very flexible shaft that can rotate the attached piezoelectric transducer in 360^o, and it contains wires to carry driving signals to and receiving signals from the piezoelectric transducer.  The piezoelectric transducer is designed to have an angle with respect to the axis that no “ring-down effect” will occur caused by the acoustic dome.  This dome is designed to be acoustically transparent and thus no “dead zone” is occurred in this design (Link to Limitations of IVUS).  In this way, this IVUS can increase the quality of its image and need not perform liquid-filling technique to increase the quality of image.

 (2) Intravascular echo element with a stationary transducer and a rotating deflection mirror

        The following picture is a schematic of IVUS catheter with a stationary transducer and a rotating deflection mirror.  Its technique is similar to the Mechanically rotating intravascular echo element.  The differences are the piezoelectric transducer is fixed, and thus can avoid the need to use a rotating electric wire in the flexible shaft.  

　

　

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