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Human magnetic resonance imaging at 8 T
Author(s) -
Robitaille P.M. L.,
Abduljalil A. M.,
Kangarlu A.,
Zhang X.,
Yu Y.,
Burgess R.,
Bair S.,
Noa P.,
Yang L.,
Zhu Hui,
Palmer B.,
Jiang Z.,
Chakeres D. M.,
Spigos D.
Publication year - 1998
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/(sici)1099-1492(199810)11:6<263::aid-nbm549>3.0.co;2-0
Subject(s) - excitation , specific absorption rate , sinc function , nuclear magnetic resonance , adiabatic process , magnetic field , magnetic resonance imaging , spins , physics , energy (signal processing) , pulse (music) , spin (aerodynamics) , field (mathematics) , resonance (particle physics) , absorption (acoustics) , atomic physics , optics , computer science , condensed matter physics , medicine , quantum mechanics , telecommunications , mathematics , detector , antenna (radio) , pure mathematics , computer vision , radiology , thermodynamics
In this work, we present the first human magnetic resonance image (MRI) obtained at ultrahigh field strengths (8 T). We demonstrate that clinical imaging will be possible at 8 T and that reasonable quality head images can be obtained at this field strength. Most importantly, we emphasize that the power required to excite the spins at 8 T is much lower than had previously been predicted by the nuclear magnetic resonance theory. A 90° pulse in the head at 8 T requires only ∼0.085 J of energy (90 W for a 2‐lobe 4 ms sinc pulse). Based on measurements at 4 T, 1–2 J of energy should have been utilized to achieve a 90° excitation at 8 T. The fact that the energy required for spin excitation at 8 T is much lower than predicted by the NMR theory, will be extremely important to the viability of ultrahigh field imaging, since concerns related to power absorption and specific absorption rate (SAR) violations at ultrahigh field are alleviated. As such, it will be possible to utilize RF intensive pulse sequences and adiabatic spin excitation at 8 T without significant risk to the subject. © 1998 John Wiley & Sons, Ltd.