Advances in two dimensional arrays for real time volumetric imaging

The authors have previously described prototype two-dimensional arrays used for real time volumetric imaging (1991, 1992, 1995). However, these arrays primarily operated at frequencies below 3.0 MHz, have been unwieldy to the operator due to the interconnect schemes used, and have taken up to 6 weeks to construct. The authors have recently constructed transducers operating at higher frequencies, and having a smaller interconnect geometry. These transducers include a 40/spl times/40=1600 element array operating at 3.5 MHz and a 60/spl times/60=3600 element array operating at 5.0 MHz for cardiac applications. Each transducer includes 256 transmit and 256 receive elements. The authors also constructed an 80/spl times/80=6400 element array operating at 2.5 MHz on a muti-layer polyimide connector for obstetric applications. This transducer has 256 transmit and 208 receive elements. Using a flex circuit interconnect, the authors reduced the size in the transducer assembly by a factor of four compared to their previous method of pin and socket interconnects. The transducer/handle assembly is integrated with the Duke University real time volumetric imaging system capable of generating multiple planes at any desired angle and depth within the pyramidal volume.