Improving the temporal resolution of functional MR imaging using keyhole techniques

Jia Hong Gao, Jinhu Xiong, Song Lai, E. Mark Haacke, Marty G. Woldorff, Jinqi Li, Peter T. Fox

Research output: Contribution to journalArticlepeer-review

44 Scopus citations


Using a keyhole technique, it is shown that the data acquisition rate of gradient-echo imaging for functional MRI (fMRI) studies can be increased substantially. The resulting enhancement of the temporal resolution of fMRIs was accomplished without modifying the hardware of a conventional MRI system. High spatial resolution fMRI images were first collected with conventional full k-space acquisition and image reconstruction. Using the same data set, simulation reconstruction using the keyhole principle and zero-padding were performed for comparison with the full k-space reconstruction. No significant changes were found for fMRI images generated from the keyhole technique with a data sharing profile of 50% of the k-space. As k-space data sharing profiles increased to 75 and 87.5%, the keyhole fMRI images began to show only modest changes in activation intensity and area compared with the standard images. In contrast, zero-padding fMRI images produced a significant disparity both in activation intensity and area relative to the truly high- resolution fMRI images. The keyhole technique's ability to retain the intensity and area of fMRI information, while substantially reducing acquisition time, makes it a promising method for fMRI studies.

Original languageEnglish (US)
Pages (from-to)854-860
Number of pages7
JournalMagnetic Resonance in Medicine
Issue number6
StatePublished - Jun 1996


  • Functional MRI
  • keyhole
  • motor
  • temporal resolution

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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