Ultrasound transducer for transesophageal imaging

Abstract

Transesophageal echocardiography is implemented using a miniature transversely oriented transducer that is preferably small enough to fit in a 7.5 mm diameter probe, and most preferably small enough to fit in a 5 mm diameter probe. Signal processing techniques improve the depth of penetration to the point where the complete trans-gastric short axis view of the left ventricle can be obtained, despite the fact that the transducer is so small. The reduced diameter of the probe (as compared to prior art probes) reduces risks to patients, reduces or eliminates the need for anesthesia, and permits long term direct-visualization monitoring of patients' cardiac function.

1 . An ultrasound transducer comprising:
 a plurality of piezoelectric elements, each of the elements having a height in the elevation direction and a thickness in the azimuthal direction,   wherein the elements are stacked in the azimuthal direction in a linear array to form a phased array ultrasound transducer, such that the resulting linear array has a height in the elevation direction and a width in the azimuthal direction, and   wherein the height-to-width ratio of the linear array is at least about 1:1.   
     
     
         2 . The ultrasound transducer of  claim 1 , wherein the size of the transducer in the elevation direction is at least about 4 mm. 
     
     
         3 . The ultrasound transducer of  claim 1 , wherein the size of the transducer in the elevation direction is at least about 6 mm. 
     
     
         4 . The ultrasound transducer of  claim 1 , wherein the size of the transducer in the elevation direction is at least about 8 mm. 
     
     
         5 . The ultrasound transducer of  claim 1 , wherein the size of the transducer in the elevation direction is about 10 mm. 
     
     
         6 . The ultrasound transducer of  claim 1 , wherein the height-to-width ratio of the linear array is at least about 1.5:1 
     
     
         7 . The ultrasound transducer of  claim 1 , wherein the height-to-width ratio of the linear array is about 2:1 
     
     
         8 . The ultrasound transducer of  claim 7 , wherein the transducer is a phased-array transducer. 
     
     
         9 . The ultrasound transducer of  claim 7 , wherein the size of the transducer in the elevation direction is about 10 mm. 
     
     
         10 . The ultrasound transducer of  claim 1 , wherein the transducer is a phased-array transducer. 
     
     
         11 . The ultrasound transducer of  claim 1 , wherein the transducer has between about 32 and 40 active elements. 
     
     
         12 . The ultrasound transducer of  claim 1 , wherein the transducer has between about 32 and 40 active elements, and the elements are spaced at a pitch of about 125-128 microns. 
     
     
         13 . The ultrasound transducer of  claim 1 , wherein the transducer has between about 24 and 48 active elements, and the elements are spaced at a pitch of about 100-150 microns.