Acquisition of human multislice MR images at 8 Tesla.

PURPOSE The purpose of this work was to acquire high quality multislice MR images from the human brain at 8 Tesla (T). METHOD Initial images were acquired with an 8 T/80 cm magnet designed and manufactured by Magnex Scientific (Abingdon, England). Images were acquired using volume RF coils operating at 340 MHz. A torque-free head gradient insert was utilized to spatially encode the spins. Images were acquired from the human head using gradient-recalled echo pulse sequences. RESULTS Ultra high frequency (UHF) MR images have been obtained from the human head that display both excellent signal/noise ratio and image quality. The power required to obtain the 8 T images was much less than expected based on the trend obtained at lower fields. CONCLUSION In this work, we have demonstrated that it is possible to obtain high quality multislice images from the human brain at 8 T. These images display the phenomenal potential for imaging at UHF and reveal that none of the stumbling blocks advanced by the MR community for an 8 T project (RF penetration, dielectric effects, specific absorption rate problems, RF power requirements) proved to be a limitation.

[1]  P. Lauterbur,et al.  Image Formation by Induced Local Interactions: Examples Employing Nuclear Magnetic Resonance , 1973, Nature.

[2]  R S Balaban,et al.  The design and test of a new volume coil for high field imaging , 1994, Magnetic resonance in medicine.

[3]  J Vetter,et al.  Whole-body MR imaging and spectroscopy with a 4-T system. , 1988, Radiology.

[4]  D. Leibfritz,et al.  Pre-operative localized in vivo proton spectroscopy in cerebral tumors at 4.0 Tesla--first results. , 1989, Magnetic resonance imaging.

[5]  D A Ortendahl.  Whole-body MR imaging and spectroscopy at 4 T: where do we go from here? , 1988, Radiology.

[6]  G. Ries,et al.  A 4-tesla superconducting whole-body magnet for MR imaging and spectroscopy , 1988 .

[7]  S. Ogawa,et al.  BOLD Based Functional MRI at 4 Tesla Includes a Capillary Bed Contribution: Echo‐Planar Imaging Correlates with Previous Optical Imaging Using Intrinsic Signals , 1995, Magnetic resonance in medicine.

[8]  Jullie W Pan,et al.  High frequency volume coils for clinical NMR imaging and spectroscopy , 1994, Magnetic resonance in medicine.

[9]  A. Kangarlu,et al.  Human magnetic resonance imaging at 8 T , 1998, NMR in biomedicine.

[10]  Jullie W Pan,et al.  3D 31P Spectroscopic Imaging of the Human Heart at 4.1 T , 1995, Magnetic resonance in medicine.

[11]  C N Chen,et al.  The field dependence of NMR imaging. II. Arguments concerning an optimal field strength , 1986, Magnetic resonance in medicine.

[12]  P. Röschmann,et al.  Spectroscopy and imaging with a 4 tesla whole‐body mr system , 1988, NMR in biomedicine.

[13]  R. Ladebeck,et al.  In vivo magnetic resonance imaging and spectroscopy of humans with a 4 t whole‐body magnet , 1990, NMR in biomedicine.

[14]  C J Hardy,et al.  Rapid 31P spectroscopy on a 4‐T whole‐body system , 1988, Magnetic resonance in medicine.

[15]  A M Abduljalil,et al.  Torque free asymmetric gradient coils for echo planar imaging , 1994, Magnetic resonance in medicine.

[16]  R. Turner,et al.  Functional mapping of the human visual cortex at 4 and 1.5 tesla using deoxygenation contrast EPI , 1993, Magnetic resonance in medicine.

[17]  Peter Andersen,et al.  Mental Rotation Studied by Functional Magnetic Resonance Imaging at High Field (4 Tesla): Performance and Cortical Activation , 1997, Journal of Cognitive Neuroscience.

[18]  R S Balaban,et al.  MR relaxation times in human brain: measurement at 4 T. , 1996, Radiology.

[19]  R S Balaban,et al.  MR imaging contrast in human brain tissue: assessment and optimization at 4 T. , 1996, Radiology.

[20]  P A Bottomley,et al.  Power deposition in whole-body NMR imaging. , 1981, Medical physics.

[21]  D. Hoult,et al.  The field dependence of NMR imaging. I. Laboratory assessment of signal‐to‐noise ratio and power deposition , 1986, Magnetic resonance in medicine.