29 September 1995
Vol 269, Issue 5232

About The Cover

Propagating acoustic strain waves depicted by magnetic resonance imaging (MRI). The dual-source interference pattern arose from 500-hertz mechanical shear waves applied to a tissue-simulating gel at two points (54 millimeters apart, at left). The MRI technique used can quantitatively depict mechanical waves with amplitudes on the order of hundreds of nanometers and could lead to the development of a medical imaging modality that emulates the clinical technique of palpation. See page 1854. [Image: Richard L. Ehman]