Jan Sedlacik1, Jrgen R. Reichenbach2, Ferdinand Schweser2
1Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 2Medical Physics Group, Institute of Diagnostic and Interventional Radiology I, University Hospital-Friedrich Schiller University Jena, Jena, Germany
Due to diffusion effects, the transverse relaxivity caused by small iron particles depends on the particles size. Consequently, the same amount of iron can cause very different relaxation rates for particles of different size compromising relaxation-based iron quantification measurements. However, the bulk frequency shift is supposed to be determined by the average magnetic susceptibility of the solution and, therefore, independent of particle size, aggregation or distribution. The purpose of this work was to investigate this theoretical behavior in a phantom experiment and to discuss implications for future in vivo studies.