A new transducer technology--the annular phased array: comparison with a conventional mechanically rotating sector transducer: the upper abdomen.

During a 3-month period, 285 patients underwent ultrasonographic examination of the upper abdomen. Scanning was done with a new annular phased array transducer, and a conventional rotating sector transducer. Our study indicates that the annular phased array is more effective for outlining boundaries of the liver, spleen and pancreas in the near and far field. Owing to improved lateral resolution, the new technology permits US imaging of parenchymal organs, even in cases of severe bowel gas obscuration.