Perfusion imaging by un-inverted flow-sensitive alternating inversion recovery (UNFAIR)

J. A. Helpern, C. A. Branch, M. N. Yongbi, N. C. Huang

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


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 except that the spins in the image slice of interest always have +z magnetization and the in-flowing spins are alternately inverted and uninverted. CBF-weighted images of rat brain under conditions of normocpnia and 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.

Original languageEnglish (US)
Pages (from-to)135-139
Number of pages5
JournalMagnetic Resonance Imaging
Issue number2
StatePublished - 1997
Externally publishedYes


  • Cerebral blood flow
  • Magnetic Resonance Imaging
  • Perfusion

ASJC Scopus subject areas

  • Biophysics
  • Biomedical Engineering
  • Radiology Nuclear Medicine and imaging


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