Correlation of Fat Signal from Dixon Imaging with 18F-FDG Accumulation Using an Integrated PET/MR System

Steffen Renisch¹, Susanne Heinzer², Holger Eggers¹, Osman Ratib³, Peter Brnert¹

The combination of PET and MR can increase the diagnostic value of both modalities due to the additional information becoming available. PET measures the spatial distribution of an appropriate tracer while MR offers a huge variety of soft tissue contrasts, like T1, T2 , diffusion and water and fat. For the latter Dixon imaging has been developed yielding excellent fat suppression and also clinically useful information about the fat distribution and its content in specific tissues [1]. Current literature shows [2] that there generally is limited 18F- Deoxyglucose (FDG) and 18F-Choline (FCH) [4] uptake in tissue with a high fat content. Therefore, the information about the fat content might be very useful in PET image interpretation. Integrated PET/MR platforms, now becoming available, enable the combination of anatomical information and information about the fat content from the Dixon images with the functional information stemming from the 18F-FDG- and 18FCH PET due to the intrinsic registration of PET and MR data. In this patient study, we demonstrate a correlation between fat void regions and FDG/FCH uptake. This information may serve for partial volume correction in PET reconstruction and permits further characterization of disease.