Prospective evaluation of planar bone scintigraphy, SPECT, SPECT/CT, 18F-NaF PET/CT and whole body 1.5T MRI, including DWI, for the detection of bone metastases in high risk breast and prostate cancer patients: SKELETA clinical trial

Purpose. Detection of bone metastases in breast and prostate cancer patients remains a major clinical challenge. The aim of the current trial was to compare the diagnostic accuracy of Tc-99m-hydroxymethane diphosphonate (Tc-99m-HDP) planar bone scintigraphy (BS), Tc-99m-HDP SPECT, Tc-99m-HDP SPECT/CT, F-18-NaF PET/CT and whole body 1.5 Tesla magnetic resonance imaging (MRI), including diffusion weighted imaging, (wbMRI+DWI) for the detection of bone metastases in high risk breast and prostate cancer patients.Material and methods. Twenty-six breast and 27 prostate cancer patients at high risk of bone metastases underwent Tc-99m-HDP BS, Tc-99m-HDP SPECT, Tc-99m-HDP SPECT/CT, F-18-NaF PET/CT and wbMRI+DWI. Five independent reviewers interpreted each individual modality without the knowledge of other imaging findings. The final metastatic status was based on the consensus reading, clinical and imaging follow-up (minimal and maximal follow-up time was 6, and 32 months, respectively). The bone findings were compared on patient-, region-, and lesion-level.Results. Tc-99m-HDP BS was false negative in four patients. In the region-based analysis, sensitivity values for Tc-99m-HDP BS, Tc-99m-HDP SPECT, Tc-99m-HDP SPECT/CT, F-18-NaF PET/CT, and wbMRI+DWI were 62%, 74%, 85%, 93%, and 91%, respectively. The number of equivocal findings for Tc-99m-HDP BS, Tc-99m-HDP SPECT, Tc-99m-HDP SPECT/CT, F-18-NaF PET/CT and wbMRI+DWI was 50, 44, 5, 6, and 4, respectively.Conclusion. wbMRI+DWI showed similar diagnostic accuracy to F-18-NaF PET/CT and outperformed Tc-99m-HDP SPECT/CT, and Tc-99m-HDP BS.