Ultra-high field MRI (3 teslas and more)

  • Antoine Micheau, MD , Denis Hoa, MD
    • Antoine Micheau, MD : IMAIOS, 2 All Charles R. Darwin, Island Hall 2 34170 Castelnau Le Lez
    • Denis Hoa, MD : IMAIOS, 2 All Charles R. Darwin, Island Hall 2 34170 Castelnau Le Lez
  • Friday, December 2, 2022
  • ISBN 978-1847537768

Learning objectives

After reading this chapter, you should be able to:

  • State the consequences of increasing the magnetic field on signal-to-noise ratio, relaxation times, SAR, artifacts, acoustic noise
  • Describe the necessary adaptations in sequence parameters and equipment
  • Set out the advantages and disadvantages of increasing magnetic field
  • List the potential fields of application of ultra high field MRI

Key points

 3,0 T vs 1,5 TAdvantages & ApplicationsDisadvantages & Solutions
SNR↑ image quality
↑ speed
↑ spatial resolution
T1↑ ~↑ blood/tissue contrast
TOF MRA
↓ Gadolinium doses
↑ TR or ↓ signal
Modification of tissue contrasts
Magnetization preparation (inversion, MP…)
T2?Drop in signal
↓ TE
SAR↑↑RF energy deposited (SAR limit)
Parallel acquisition
↓ flip angle, echo train, number of slices
↑ TR
Chemical shift↑ differences in resonance frequency
Better fat suppression
Spectroscopy
Chemical shift artifacts
↑ bandwidth
Fat signal suppression
Adaptation of in-phase / out-of-phase TE
Magnetic susceptibility↑↑Greater sensitivity to magnetic susceptibility
Better detection of hemorrhages
Perfusion MRI (DSC MRI)
Functional MRI (BOLD)
Magnetic susceptibility artifacts
Parallel acquisition
↓ TE
Dielectric effectsRF heterogeneities, variable signal loss in the image
Optimization of coils,
Parallel RF transmission
Acoustic noiseVacuum magnet housing
Headphones, gradient downgrade

 

References

  1. Willinek and Kuhl. 3.0 T neuroimaging: technical considerations and clinical applications. Neuroimaging clinics of North America. 2006 May;16(2):217-28, ix.
  2. Tanenbaum. Clinical 3T MR imaging: mastering the challenges. Magnetic resonance imaging clinics of North America. 2006 Feb;14(1):1-15.
  3. Heidemann, Seiberlich. Perspectives and limitations of parallel MR imaging at high field strengths. Neuroimaging clinics of North America. 2006 May;16(2):311-20, xi.
  4. Voss, Zevin. Functional MR imaging at 3.0 T versus 1.5 T: a practical review. Neuroimaging clinics of North America. 2006 May;16(2):285-97, x.
  5. Merkle and Dale. Abdominal MRI at 3.0 T: the basics revisited. Ajr. 2006 Jun;186(6):1524-32.
  6. Mosher. Musculoskeletal imaging at 3T: current techniques and future applications. Magnetic resonance imaging clinics of North America. 2006 Feb;14(1):63-76.
  7. Gutberlet, Noeske. Comprehensive cardiac magnetic resonance imaging at 3.0 Tesla: feasibility and implications for clinical applications. Investigative radiology. 2006 Feb;41(2):154-67.