[18F]FDG and [18F]fluoride PET-CT and MRI images of patients 1 (a-e) and 2 (f-j). Both patients underwent an extra [18F]fluoride PET-CT scan. Coronal PET (a, c, f, h) and PET-CT (b, d, g, i) images obtained with [18F]FDG (a, b, f, g) and [18F]fluoride (c, d, h, i). Multiple hotspots are shown; two examples are indicated by the red closed arrows (c, h). (e) Sagittal MRI image (STIR) of vertebral column and (j) coronal/oblique MRI (STIR) of sacroiliac joints. Multiple lesions with increased signal (bone marrow edema) are shown; an example is indicated by the open arrow. [18F]FDG, [18F]-fluoro-2-deoxy-D-glucose; MRI, magnetic resonance imaging; PET, positron emission tomography; PET-CT, positron emission tomography-computed tomography; STIR, short-tau inversion recovery.