Cooperative T 1 and T 2 effects on contrast using a new driven inversion spin‐echo (DISE) MRI pulse sequence

A pulse sequence is presented for obtaining a single image with combined T 1 /T 2 weighting. T 2 relaxation is made to increase intensity, in cooperation with the effect of T 1 relaxation, by providing T 2 weighting with a 90°‐180°‐90° driven inversion pulse triplet in an inversion recovery method. Unlike the inversion spin‐echo method having a short inversion time (TI), signals in the new driven inversion spin‐echo (DISE) method need not be negative and the most T 1 ‐sensitive region of the recovery curve can be used. Selecting sensitivity to one relaxation time does not degrade the sensitivity to the other relaxation time. T 1 sensitivity is thus extended to longer echo times (TE intervals), T 2 sensitivity is extended to longer TI intervals, and the combined T l / T 2 ‐weighted technique with intermediate TE and T 1 has highly cooperative and near‐maximal T 1 and T 2 effects on contrast. Intensity is not multiplicatively degraded by T 1 and T 2 weighting so that the signal‐to‐noise of the combined T 1 / T 2 ‐weighted method is high. High intensity and T I and T 2 cooperatively occur for a much wider range of relaxation times, and especially for images heavily weighted to the pathologic intermediate and long T 1 and T 2 Rgime. © 1990 Academic Press, Inc.