Turbo (fast) spin-echo at 0.5 T: influence of echo distance and echo number on image contrast

Signal intensities, signal-to-noise ratios (S/N), and contrats-to-noise ratios (C/N) in dependence on the echo distance and echo number of the new turbo (fast) spin-echo technique are analysed by phantom, volunteer and patient measurements. With increasing echo number (3 to 15 echos), signal intensities increase (25 to 50%), S/N varies between different tissues, and C/N of fat to water decreases (70%). A high echo number, although it shortens the imaging time, is thus not always the best choice since the fat/water contrast is lost. However, a high fat/water contrast is advantageous for several MR applications. (orig.)