Thomas L. Szabo, Biomedical Engineering Department, Boston University
In the last decade, several remarkable technological developments have made new applications possible in medical ultrasound. Miniature one-dimensional phased arrays have been in use for over 30 years for real-time diagnostic ultrasound imaging of the body as well as the visualization of blood flow.
Moore’s law (reduction of size of electronics over time), application specific integrated circuits (ASICs), digital and signal processing (DSP) chips, and higher-speed computation and software have contributed to the shrinking of diagnostic ultrasound systems. Now lower cost, pocket-sized, wireless and mobile phone imaging systems are opening up new global applications and transforming the way ultrasound can be used. New inventions such as microbeamforming as well as Moore’s law have made possible two-dimensional or matrix arrays for real-time three-dimensional imaging with thousands of array elements without increasing the size of the imaging system. From 2000 to 2011, the number of procedures using ultrasound grew tenfold and was roughly 10 times the number of procedures by CT and MRI combined.
Image fusion is the combination of two-dimensional ultrasound imaging with complementary co-registered imaging modalities. Shear wave elastography is generating higher-contrast images than those using conventional longitudinal waves. New imaging methods employing plane waves are increasing frame rates by two orders of magnitude. Therapeutic ultrasound has enabled knifeless surgery. Focusing delays sent to thousands of elements in a hemispheric array are corrected for aberrations through the skull to focus high-intensity ultrasound with pinpoint accuracy on tumors and targets in the brain through intact skulls. Reconfigurable ultrasound research systems with open software are spawning new applications and startups. MATLAB® plays a key role in ultrasound research, simulation and research systems.