Detection of superior sagittal sinus thrombosis on FDG PET

A 51-year-old woman with infiltrating ductal carcinoma of left breast, who postsurgery, chemotherapy, and external radiotherapy presented with recurrence in the right chest wall a year after completion of treatment. An excision biopsy of the right chest wall nodule showed deposits of infiltrating ductal carcinoma. She also complained of excruciating headache. A FDG PET scan was done an hour after intravenous administration of 444 MBq (12 mCi) of F-18 FDG, on a dedicated PET scanner. The scan showed multiple hypermetabolic sites in the mediastinum, liver, spleen, abdomen, right scapula, and right ilium. In addition to all this, a triangular area of uptake was seen along the falx in the region of the superior sagittal sinus. A CT scan confirmed a superior sagittal sinus thrombosis. On contrast-enhanced CT scan an "empty delta sign" was observed in the superior sagittal sinus from enhancement of the dural leaves surrounding the comparatively less dense thrombosed sinus. This sign is highly diagnostic for sagittal sinus thrombosis.