The conventional gradient-recalled echo technique, FLASH, has widely been used for functional MRI. FLASH results at 4 T with short TEs of 10-20 ms mimic those at 1.5 T with TEs of 25-50 ms or longer. Under these conditions, large venous vessels dominate the activated area; however, the use of longer TEs at 4 T reveals activation in gray matter areas as well as large vessels. Inflow effects of large vessels can be greatly reduced with centric-reordering of phase-encoding steps and inter-image delay. Finger and toe movement paradigms show that functional activation maps are consistent with classical somatotopic maps, and are specific to the tasks. Navigator-based motion correction generates functional maps with larger activation areas by reducing physiological noise.

It is well known that the signal polarity in inversion-recovery (IR) images changes with inversion time, complicating the determination of T1. To avoid this problem, a simple subtraction method is implemented. In this method, k-space data of the longest inversion time are subtracted from the corresponding data of each inversion time. This subtraction yields IR images of same polarity, making it straightforward to derive T1 using a standard fitting routine. Phantom T1 studies with IR Turbo-FLASH images demonstrate that this technique is robust and accurate. Four Tesla T1 values of the human brain were also determined by this method to demonstrate its in vivo utility.

A technique is presented for MRI tagging in the presence of inhomogeneous B1 fields. A rectangular tagging grid is produced with B1-insensitive adiabatic pulses in a magnetization preparation period that precedes image acquisition. Phantom results demonstrate that the method is well-suited to surface coil experiments. The technique is applied to a canine model of myocardial ischemia to track the spatially dependent wall motion of the left ventricle during the cardiac cycle. Transmural 31P spectra are acquired from the same double-tuned surface coil, with tagging and spectroscopy performed for the first time, during normal, ischemic, and recovery conditions for the same animal.