Advanced intraosseous migration (Type III-b) of a supraspinatus calcification with spontaneous resolution at follow-up. A. Initial anteroposterior (AP) radiograph showing the calcific deposit. B. Coronal MRI revealing intraosseous extension of the deposit with associated bone marrow edema. C. Oblique sagittal MRI demonstrating the “hourglass sign,” indicating tendon-to-bone continuity. D. Follow-up AP radiograph two years later showing complete disappearance of the calcification. E. Coronal MRI confirming resolution of the intraosseous deposit. F. Oblique sagittal MRI showing complete resolution of both the calcification and bone marrow edema.