First clinical experience with simultaneous whole body MR/PET imaging

2309 Objectives With the advent of integrated MR/PET instrumentation, simultaneous acquisition of MR and PET data has become possible. We describe our first experience with a fully integrated whole body MR/PET scanner in a series of oncologic patients. Methods Twenty-three patients with oncologic diseases underwent MR/PET (Siemens Biograph mMR) following a PET/CT investigation with F-18-FDG (21 patients 93-201 min p.i.) or C-11-Choline (2 patients 53-67 min p.i.). Depending on the diagnostic question, various imaging protocols were employed consisting of 3 to 5 bed positions (26 cm each) with a duration ranging from 5 to 10 min. Specially designed PET compatible head-neck and body matrix coils were used. Attenuation correction was based on a DIXON MR sequence three-tissue segmentation, which required 16 s/ bed position during breath hold. This acquisition was followed by coronal T2-tirm (acquisition time: 120 s; 180 s in abdominal and thoracic regions with navigator) and T1-tse (acquisition time: 90 s) weighted MR sequences. Simultaneously, PET data were acquired (5 to 10 min) and iteratively reconstructed (3 iterations; 21 subsets; base resolution 172; zoom 1; filter Gaussian 4 mm FWHM). Results Various imaging protocols ranging from 15 to 40 min were performed successfully and were well tolerated by all patients. Simultaneous whole body MR/PET imaging including multiple MR sequences was feasible within this time frame resulting in inherently co-registered MR and attenuation corrected PET images. Conclusions These first results indicate, that whole body MR/PET imaging including multiple MR sequences is possible within an acceptable time frame. Imaging protocols need to be refined based on the clinical requirements