High-sensitivity single-shot perfusion-weighted fMRI

A method is presented for measurement of perfusion changes during brain act ivation using a single-shot pulsed spin labeling technique. By employing a double-inversion labeling strategy, stationary tissue (background) signal w as suppressed while minimally affecting perfusion sensitivity. This allowed omission of the otherwise required reference scan, resulting in twofold-im proved temporal resolution. The method was applied to visual and motor cort ex activation studies in humans, and compared to standard FAIR-type perfusi on labeling techniques. Experiments performed at 1.5T and 3.0T indicate a c lose to 90% suppression of background signal, at a cost of an 11% and 9%, r espectively reduction in perfusion signal. Combined with the twofold increa se in signal averaging, and a reduction in background signal fluctuations, this resulted in a 64% (1.5T, N = 3) and a 128% (3T, N = 4) overall improve ment in sensitivity for the detection of activation-related perfusion chang es. Published 2001 Wiley-Liss, Inc.(dagger)