Evaluation of F-Fluoride PET/MR and PET/CT in patients with unclear foot pain

To evaluate the quality and diagnostic performance of F-Fluoride positron-emission tomography/magnetic resonance imaging (F-Fluoride PET/MR) compared to F-Fluoride positron-emission tomography/computed tomography (F-Fluoride PET/CT) imaging in patients with unclear foot pain. Methods: Twenty-two patients (9 men, 13 women; mean age 48±18 years, range: 20–78 years) were prospectively included in this study and underwent a single injection dual imaging protocol with F-Fluoride PET/CT (Siemens Biograph mCT) and PET/MR (Siemens Biograph mMR). PET/MR protocol included at least T1w SE and PD fs sequences in two planes each with simultaneous acquisition of PET over 20min. PET/CT included a native isotropic (0.6mm) diagnostic CT (120kV, 90mAs) and a subsequent PET (2min per bed position (BP)). Two blinded readers assessed in consensus randomly both PET datasets for image quality (three-point scale) and for the presence of focal lesions with increased F-Fluoride uptake (maximum of 4 lesions). For each dataset (PET/CT vs. PET/MR) the diagnoses were defined by using both PET and morphological dataset. SUV values from the two devices were compared using linear correlation and Bland-Altman plots. Moreover we estimated the potential for dose reduction for PET/MR compared to PET/CT considering the longer acquisition time of PET/MR analyzing count rate statistics. Results: Image quality was rated diagnostic for both PET datasets. However, with a mean rating of 3.0/3 for PET/MR and 2.3/3 for PET/CT, image quality was significantly superior for PET/MR (p<0.0001). Sensitivity of the PET datasets in PET/MR and PET/CT were equivalent with the same 42 lesions with focal F-Fluoride uptake. In PET/MR mean SUVmean was 10.4 [range 2.067.7] and mean SUVmax 15.6 [range 2.9-94.1], corresponding mean SUVmean of PET/CT was 10.2 [range 1.8-55.6] and mean SUVmax 16.3 [range 2.5-117.5], resulting in a high linear correlation by on September 30, 2017. For personal use only. jnm.snmjournals.org Downloaded from