Pediatric volumetric ultrasound scanner

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Hundreds of millions of ultrasound (US) exams are performed each year worldwide. Typical limitations of conventional US imaging include operator dependence, limited field of view, limited contrast, and diffraction- limited resolution. Volumetric imaging has the potential to create an operator-independent acquisition protocol, and ultrafast US acquisition has opened new opportunities to address field-of-view and contrast issues. Our extended aperture approach applied here addresses spatial resolution limitations as well. With high resolution, real-time imaging capabilities and the lack of ionizing radiation, US has great promise for imaging pediatric patients; in particular, for children under 3 who cannot be imaged with MRI or CT without anesthesia, the development of a high-resolution volumetric US scanner would be transformative. In particular, we set out to image the pediatric liver and kidney within ~0.1 second, which requires a technological leap. New ASIC switch matrices will enable high speed acquisition and GPU-based partial beam formation enables the visualization of the 3D data. Reconstruction of the 3D vascular structure facilitates image-based recognition of the anatomical location of a lesion. Ultrafast SVD Doppler imaging allows the visualization of very small blood vessels with blood flow velocities as low as 4 mm/s. Abdominal pain is very common in children and US is frequently used to determine the cause. Accurate volumetric measurements of the kidney are problematic due to patient motion and operator-dependent scanning. Assaying the liver and abdomen, particularly in the context of trauma are similarly important. Thus, we seek to create this real-time imaging tool with resolution that exceeds CT and MR but without the need for anesthesia or radiation. Using 1024 active system channels with integrated GPU beamformers, we will create 2 transducers to span the needs of children for this technology, with spatial resolution at 5 cm (~300 (azimuth) x 600 (elevation) x 300 (depth) µm) that should exceed that offered by MRI or CT by several fold. The array will be realized using tiled modules that can be switched in a mode-dependent fashion to accomplish B-mode imaging, color Doppler and contrast imaging. Over the past four years, Stanford University and the University of Southern California have designed an adult extended-aperture abdominal- imaging system, and demonstrated the improved spatial resolution, field of view and contrast that can be achieved. We exploit these tools here to develop a dedicated pediatric volumetric scanner. Our aims to accomplish this are to 1) create and integrate acoustic/electronic transducers to implement signal buffering and multiplexing; and 2) develop volumetric software and conduct pediatric imaging studies as a proof of concept. We will develop the software and systems, test the system components on adult volunteers and phantoms, and develop 3D volumetric processing. We will image a cohort of pediatric patients spanning 3D kidney volumetric mapping, detection and mapping of previously detected liver lesions. In each case, MRI will provide the gold standard.