Multiple‐spin‐echo imaging with a 2D Fourier method

In 2D Fourier imaging the normal Carr‐Purcell multiple‐echo sequence generally leads to center line and mirror artifacts caused by imperfect rotations by the rf pulses. We describe a method to avoid these distortions using a phase alternating‐ p hase shift (PHAPS) sequence which also allows multiple‐slice and multiple‐echo imaging at the same time. Measuring phantoms with calibrated T 2 values, we have shown that the PHAPS imaging sequence leads to an accuracy of quantitative T 2 determinations of better than 10%. Contrast‐enhanced images are presented which we calculated from multiple‐echo images and extrapolated to arbitrary echotimes, including negative ones. We believe that these improvements in T 2 imaging will result in a significant reduction of patient investigation time in magnetic resonance imaging. © 1986 Academic Press, Inc.