Polycythemia mimicking venous sinus thrombosis

Abstract

Venous sinus thrombosis is a relatively uncommon disorder that frequently is associated with confusing clinical findings and delayed diagnosis. Patients are often screened with unenhanced CT, and CT findings may be subtle and may include hyperattenuation of cerebral veins or venous sinuses secondary to intracranial thrombosis. This hyperattenuation may be mimicked by polycythemia, as shown in this case.

Fig 1.

Unenhanced CT scans of the brain. A, Hyperattenuation in midline of the posterior fossa (arrow) was initially misinterpreted as cerebellar hemorrhage and later misinterpreted as sinus thrombosis. B and C, Higher sections reveal abnormally increased attenuation of straight sinus and superior sagittal sinus (arrows) caused by polycythemia.

Fig 2.

MR images and time-of-flight MR venogram of the brain. A, Axial proton density-weighted (6200/105/1 [TR/TE/NEX]) MR image reveals normal flow voids in the straight sinus and sagittal sinus. B, Contrast-enhanced T1-weighted (414/17/1) image reveals normal flow in the venous sinuses. C, Time-of-flight MR venogram (30/6) shows normal flow in the straight sinus and superior sagittal sinus.