Two New Pulse Sequences for Efficient Determination of Tissue Parameters in MRI

Abstract

In clinical magnetic resonance (MR) imaging, results at several different repetition times (TR) are often desired. Short-TR short-TE pulse sequences are used to generate “T1-weighted” images, while long-TR long-TE sequences are generally used to derive “T2-weighted” images. Often it is necessary to have both sets, as the multiple images acquired of a given slice are used together to delineate morphology, detect pathology, and differentiate materials. In addition to acquiring both T1- and T2-related information, another consideration is the need to acquire image data quickly. In particular it is useful to generate images which can be used for T1 estimation with reduced scanning times. We have addressed these two issues of multiple-TR images and short scan time T1-weighted images with the development of two pulse sequences. The first we call an asymmetric-TR (ATR) multislice pulse sequence (Farzaneh et al. 1988), and the second is a spoiled FLASH pulse sequence (Wang and Riederer, in press). We discuss some of the details of these two sequences in this paper.