PERFUSION IMAGING BY UN-INVERTED FLOW-SENSITIVE ALTERNATING INVERSION-RECOVERY (UNFAIR)

A new pulse sequence for estimating cerebral blood flow called UNFAIR, which uses a combination of sequential hyperbolic secant preparatory pulses, is introduced. This sequence is based on the same generalized conditions as previously introduced inversion recovery techniques exce pt that the spins in the image slice of interest always have +z magnet ization and the in-flowing spins are alternately inverted and uninvert ed. CBF-weighted images of rat brain under conditions of normocpnia an d hypercapnia are presented and demonstrate the expected CBF response. A model describing the signal response to this pulse sequence is also presented and compared with in-vivo data acquired from gray and white matter. (C) 1997 Elsevier Science Inc.