Neil P. Jerome1, James A. d'Arcy1, Matthew R. Orton1, Thorsten Feiweier2, Dow-Mu Koh3, Martin O. Leach1, David John Collins1
1Radiotherapy & Imaging, The Institute of Cancer Research, Sutton, Surrey, United Kingdom; 2Imaging & Therapy Division, Siemens AG, Healthcare Sector, Erlangen, Germany; 3Department of Radiology, Royal Marsden Hospital, Sutton, Surrey, United Kingdom
Diffusion-weighted MRI in the body must account for a microcirculation fraction, separate to self-diffusion, within imaging voxels. Explicit control of diffusion pulse length and delay allows reproducible application of diffusion gradients with varying echo times; calculation of mono-exponential T2 estimates with applied gradients of b=0 and b=200 s/mm2 shows significant changes observed in liver, kidney and spleen. This suggests that the microcirculation component, with its own distinct T2, is being removed, allowing the generation of flow-free T2 maps more robustly estimating tissue T2s. This approach enables appropriate b-value choices when considering diffusion models that include or exclude microcirculation contribution.