Title :
Quantitative magnetic resonance imaging of ultrasound fields
Author :
Plewes, DB ; Walker, CL ; Foster, FS
Author_Institution :
Dept. of Med. Biophys., Toronto Univ., Ont., Canada
Abstract :
A Magnetic Resonance Imaging (MRI) technique is proposed that can be used to directly image an ultrasound (US) field in tissue in a non-invasive manner. Through the use of an oscillating magnetic field gradient, spin phase is modulated in proportion to the displacement amplitude arising from the ultrasound field. Based on MR measurements of spin displacement, pressure and intensity can also be obtained. A 5 cm diameter, focused US transducer (515 kHz) was used to direct an US field into a small MR imaging cavity surrounded by a resonant field gradient coil (0.4 Tesla/meter) while imaging with a spin-echo sequence. This allowed the clear visualization of US induced motions of less than 10 nm. Based on MR measures of these motions, measurements of US pressure, intensity and speed-of-sound can also be obtained in tissue
Keywords :
biomedical MRI; biomedical ultrasonics; 5 cm; 515 kHz; US induced motions; displacement amplitude; medical diagnostic imaging; oscillating magnetic field gradient; quantitative magnetic resonance imaging; resonant field gradient coil; spin displacement; spin phase modulation; spin-echo sequence; tissue; ultrasound fields; Amplitude modulation; Displacement measurement; Magnetic field measurement; Magnetic modulators; Magnetic resonance imaging; Phase modulation; Pressure measurement; Ultrasonic imaging; Ultrasonic variables measurement; Velocity measurement;
Conference_Titel :
Ultrasonics Symposium, 1997. Proceedings., 1997 IEEE
Conference_Location :
Toronto, Ont.
Print_ISBN :
0-7803-4153-8
DOI :
10.1109/ULTSYM.1997.661815
