Pilot prospective evaluation of ^99mTc-MDP scintigraphy, ¹⁸F NaF PET/CT, ¹⁸F FDG PET/CT and whole-body MRI for detection of skeletal metastases

Objective: The aim of this study was to compare ^99mTc-MDP bone scanning, ¹⁸F NaF PET/CT, ¹⁸F FDG PET/CT, and whole-body MRI (WBMRI) for detection of known osseous metastases. Patients and Methods: This prospective pilot trial (September 2007-April 2009) enrolled 10 participants (5 men, 5 women, 47Y81 years old) diagnosed with cancer and known osseous metastases. ¹⁸F NaF PET/CT, ¹⁸F FDG PET/CT, and WBMRI were performed within 1 month for each participant. Results: The image quality and evaluation of extent of disease were superior by ¹⁸F NaF PET/CT compared to ^99mTc-MDP scintigraphy in all patients with skeletal lesions and compared to ¹⁸F FDG PET/CT in 3 of the patients with skeletalmetastases. ¹⁸F NaF PET/CT showed osseousmetastaseswhere ¹⁸FFDG PET/CT was negative in another 3 participants. Extraskeletal metastases were identified by ¹⁸F FDG PET/CT in 6 participants. WBMRI with the combination of iterative decomposition of water and fat with echo asymmetry and leastsquares estimation, short tau inversion recovery, and diffusion-weighted imaging pulse sequences showed fewer lesions than ¹⁸F NaF PET/CT in 5 patients, same number of lesions in 2 patients, and more lesions in 1 patient. WBMRI showed fewer lesions than ¹⁸F FDG in 3 patients and same lesions in 6 patients. Conclusions: Our pilot phase prospective trial demonstrated superior image quality and evaluation of skeletal disease extent with ¹⁸F NaF PET/CT compared to ^99mTc-MDP scintigraphy and ¹⁸F FDGPET/CT, aswell as the feasibility of multisequence WBMRI. In addition, ¹⁸F FDG PET/CT provided valuable soft-tissue information that can change disease management. Further evaluation of these findings using the recently introduced PET/MRI scanners is warranted.