Neonates with suspected sinovenous thrombosis were examined by magnetic resonance venography, diffusion-weighted imaging, and T2-weighted imaging, in a study at the Massachusetts General Hospital, Boston, MA. Of 200 CT scans performed in neonates 2004-2005, 15 neonates had intracranial hemorrhage or sinovenous signal suggesting sinovenous thrombosis. The mean birth weight was 3240g and gestational age was 40 weeks. Presenting signs were seizures (60%), apnea, hypotonia, and lethargy. Twelve patients had obstetric and perinatal complications; only 1 had sepsis. MRI showed a definite intraluminal clot in the deep venous system in 2 cases, and the remainder showed decreased flow-related enhancement within the dural venous sinuses. The sinus in all these cases was compressed by subdural hematoma or sutural diastasis. Parenchymal abnormalities were present in 5, classified as hemorrhage and cytotoxic edema in 3, or vasogenic edema in 1. Four of these 5 patients showed improvements, but one died. Intraluminal clot was rare in the superficial venous system. 
COMMENT. MRI with MR venography is recommended to assess for intraluminal clot and parenchymal injury when an initial CT scan shows a suspected sinus venous thrombosis. The characteristic MR appearance in venous thrombosis is loss of the normal flow enhancement on MR venography and corresponding filling defect on T2 weighted image. Clinical signs are not specific, and MRI is essential in diagnosis of neonatal sinovenous thrombosis. Deep venous thrombosis is often associated with intraventricular or thalamic hemorrhage. One third of term neonates with intraventricular hemorrhage have cerebral sinovenous thrombosis . Obstetric complications were frequent in the above patients, and occipital bone molding may be associated with subdural or epidural hematoma leading to displacement of venous sinuses, venous hypertension and thrombosis.