Cerebral veno-occlusive disease: CT and MRI findings

ABSTRACT

Cerebral venous thrombosis [CVT] is an elusive diagnosis because of its nonspecific presentation and its numerous predisposing causes. Veno-occlusive disease of the brain most commonly affects the superior sagittal sinus followed by the transverse, sigmoid and straight sinuses. Cerebral venous thrombosis often presents with hemorrhagic infarction in areas atypical for arterial vascular distribution. It is more common than previously thought. Imaging plays a key role in the diagnosis. Magnetic resonance venography [MRV] in conjunction with t conventional MRI can accurately diagnose cerebral venous thrombosis. The aim of the study is to illustrate the spectrum of CT and MRI findings in cerebral veno-occlusive disease. In a retrospective study, twenty patients with a final diagnosis of cerebral veno-occlusive disease constituted the subjects of the study. The mode of onset was acute [first neurological symptoms or signs < 48 hours] in 8 patients and sub-acute [48 hours to one month] in 12 patients. Each patient was subjected to history taking, clinical evaluation, pre and past contrast enhanced CT scans, T1 SE, T2 SE, and FLAIR conventional MRI and together with MRV. MRI was performed immediately after CT scan in only 4/8 acute patients and delayed in mean duration of 11.3 days in the other four acute patients while it followed CT scans in all subacute twelve patients [mean duration of 1.5 days].. CT scan was unremarkable in 8/8 patients and abnormal in 12/12 patients. Abnormal findings included cerebral [8/12] or cerebellar [4/12] and the infarctions which was hemorrhagic in 5/12 patients. An empty delta sign was the only direct CT finding of CVT in only one patient MRV examination showed absent flow signals in 39 sites of thrombosis in all patients notably the superior sagittal sinus which was thrombosed in 17/20 patients followed by the transverse sinus in 13/20 patients, the sigmoid sinus in 7/20 patients and the straight sinus in 2/20 patients. Conventional MRI revealed 36 sites of dural venous sinuses thrombosis while failed to directly diagnosis two sites of superior sagittal sinus thrombosis and one site of transverse sinus thrombosis in 3/4 acute patients. CT examination in patients with suspected CVT serves mainly to depict secondary changes in the brain parenchyma, such as venous infarcts or edema and serves to exclude other abnormalities in the initial workup. The diagnosis of cerebro-vascular thrombosis occasionally can be made by CT scan with careful attention to the findings, which may be subtle. MRI combined with MRV is reliable as the sole examination for this condition