Maria A. Schmidt1, Gokhan Ertas1, James A. D'Arcy1, Anna M. Kirby2, Geoffrey S. Payne1, David J. Collins1, Nandita deSouza1, Martin O. Leach1
1MRI Unit/Cancer Research UK Clinical Magnetic Resonance Group, Royal Marsden NHS Foundation Trust and Institute of Cancer Research, Sutton, UK; 2Radiotherapy, Royal Marsden NHS Foundation Trust, Sutton, Surrey, UK
We investigate whether magnetic field inhomogeneity can cause spectrally-selective adiabatic inversion pulses to affect contrast-agent uptake curves in breast examinations. Field inhomogeneity and linewidth were measured for breast, and image intensity as a function of T1 was simulated and measured both on and off resonance. Sequence parameters must provide an approximately linear relationship between image intensity and concentration not only on resonance, but also off resonance. The off-resonance behaviour was found to differ from the on-resonance. In the presence of field inhomogeneity, sequences with spectrally selective inversion recovery are not suitable for quantitative analysis.