Investigation of Susceptibility-Induced MR Signal Dephasing in Phantom Measurements and Model Simulations for Oxygen Extraction Mapping
Bongers A, Schroeder H, Schad L
mediri GmbH, German Cancer Research Center
In view of methods currently discussed to map Oxygen-extraction in tissue, this work performed a phantom study to investigate the validity of signal-decay models used to calculate susceptibility differences from spin-echo/gradient-echo measurements. The signal-decay around a spin-echo was measured for capillary inclusions of different radii and compared to model simulations for two distinct dephasing models: One for static spin-dephasing and one with incorporation of diffusion effects. Our measurements show that a substantial diffusion effect has to be taken into account especially for small radii. This indicates that Oxygen-extraction results obtained from the static dephasing approximation might include substantial diffusion errors.