fMRI: Field Strength Issues

12/03/01


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Table of Contents

PPT Slide

Preview of Talk

Economics

So What Should the Extra Cost Buy?

Signal to Noise Considerations

Signal to Noise Considerations

Signal to Noise Considerations

Signal to Noise Considerations

Signal to Noise Considerations

Resolution and Scan Time Implications

T1 and T2 Effects

Field Dependence of T1

T1 Saturation Effects

Field Dependence of T2*

Resolution Effects on T2*

Resolution Effects on T2*

Dielectric Properties of Tissue

Frequency Dependence of Conductivity

Research Applications

BOLD Imaging

Blood Pool Origin of BOLD Response

BOLD Signal

BOLD Field Dependence

BOLD Signal Dependence with Field

1.5T and 4.0T Comparison

Effects of Physiological Noise

Effects of Physiological Noise

Effects of Respiration on B0

Effects of Respiration on B0

Effects of Physiological Noise

Effects of Physiological Noise

Correction of Physiological Noise

‘Good’ Physiological Noise

BOLD Field Comparison

ASL Perfusion Imaging at High Field

Field Dependence of PASL Sequences

Continuous ASL : Field Dependence

FAIR PWIs With Flow Crushers

Perfusion SNR Comparison

Perfusion fMRI

Perfusion and BOLD Time Courses

Special Considerations at High Field

SAR Considerations

SAR Increase with Magnetic Field

SAR Considerations

Shimming Requirements

Gradient echo Signal Loss

Within Subject Shimming

ROI Shimming

ROI Shimming

Geometric Distortion

PPT Slide

Image Unwarping

Summary Remarks

Future High Field Enhancements

Author: Peter Jezzard

Email: peterj@fmrib.ox.ac.uk

Home Page: http://www.fmrib.ox.ac.uk

Other information:
FMRIB Centre, University of Oxford, John Radcliffe Hospital, Headington, Oxford, OX3 9DU, ENGLAND