Abstract: Methods and systems are provided for three dimensional imaging with a portable diagnostic ultrasound system. Real time or four dimensional imaging with a handheld system may also be provided. A transducer array steerable in an elevation dimension is used on the portable diagnostic ultrasound system. For more rapid or simpler scanning of a volume, the transducer array is a physically steerable wobbler transducer or a transducer with a varying thickness in the elevation dimension for electronically steerable frequency dependent elevation scanning. Using a transducer array other than a fully sampled two-dimensional array may be more cost effective and may require fewer electronics within the handheld system (i.e. allow more effective miniaturization) while still providing handheld three-dimensional imaging.