Functional magnetic resonance imaging using non-Fourier, spatially selective radiofrequency encoding

✍ Scribed by Seung-Schik Yoo; Charles R.G. Guttmann; Lawrence P. Panych

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 306 KB
• Volume: 41
• Category: Article
• ISSN: 0740-3194
• DOI: 10.1002/(sici)1522-2594(199904)41:4<759::aid-mrm15>3.0.co;2-k

✦ Synopsis

A new method for functional magnetic resonance imaging (fMRI) employing non-Fourier encoding using spatially selective radiofrequency (RF) excitation is presented. The method uses manipulation of spatially selective RF pulses to encode spins in the slice-select direction. The method has several advantages over standard multislice approaches. It provides a simple means for monitoring irregularly distributed sections throughout a volume without the need to encode the whole volume. It offers the potential for increased signal-to-noise ratio if an appropriate basis is used for encoding. With a unique design of excitation pulses, it also appears possible to significantly reduce in-flow effects. An interleaved echo-planar imaging (EPI) sequence was adapted for non-Fourier encoding in the slice-select direction and was implemented on a conventional 1.5-Telsa system. The method was then used for functional mapping of the visual and motor areas where significant reduction of in-flow effect was demonstrated. This approach can be adapted to other imaging sequences that are used for fMRI, such as single-shot EPI.