Superior sagittal sinus thrombosis: neuroradiological evaluation and clinical findings.

The spectrum of clinical signs in cases of superior sagittal sinus thrombosis includes not only focal neurological deficits, seizures and mental disturbances, but also symptoms which may lead to a diagnosis of pseudotumour cerebri (PTC). In 14 cases of angiographically (or autopsy) proven thrombosis of the superior sagittal or both lateral sinuses, the "empty triangle" sign on contrast CT examination was the most reliable sign, suggesting the diagnosis in 70%. Indirect CT signs (venous infarcts) were observed in all 8 patients with focal neurological signs, but appeared rather delayed in 3 cases. In contrast, patients with "benign" intracranial hypertension or PTC (6 cases) had normal unenhanced scans (4 cases) or showed slight diffuse brain oedema (2 cases). Magnetic resonance imaging was performed in 4 patients with findings suggestive of intravascular coagulation; however, due to the complexity of flow phenomena, further studies employing this new imaging technique will first have to be performed. Thus, angiography remains the best diagnostic tool and should not be delayed if there is a clinical suspicion of thrombosis.