Aberration measurement and correction with a high resolution 1.75D array

Accurate measurement of tissue induced aberrations is necessary for effective adaptive ultrasound imaging. We acquired single channel RF data on a 6.7 MHz, 8/spl times/128 array (Tetrad Co.) operating at F/1.0 in azimuth and F/2.89 in elevation. This array was interfaced to a Siemens Elegra scanner, allowing for data acquisition during routine clinical scanning. Breast images in three patients and four volunteers (for a total of 16 scans), and thyroid and liver images in six volunteers (10 scans each) were taken. A least squares algorithm was employed to estimate the arrival time error induced by the tissue and to generate corrected images. In general, mild (20-40 nsec r.m.s.) and spatially stable aberration profiles were measured.