Effect of low hematocrit on dural venous sinus density on noncontrast CT brain
Presentation
Anticoagulated inpatient, sustained a fall and blunt head injury. ?IC bleeding
Patient Data



Striking hypodensity of the dural venous sinuses.
Status post left frontal and right parietal prior infarcts.
Signs of brain atrophy and chronic small vessel ischemic changes.
Small lytic periapical area in the mandible, likely odontogenic.
No sign of acute trauma.
Case Discussion
The perplexing low density of the dural venous sinuses in this case was explained after consulting the electronic lab records. This patient had a hematocrit of 23% shortly before imaging, resulting in an abnormally low density of the dural venous sinuses.
We would be forgiven to call this the "false empty delta sign" as the low density of the thin blood produces a similar effect on nonctrast CT as a thrombus on CT venograms resulting in the real empty delta sign.