Neuroimaging of cerebral venous thrombosis
Early and accurate diagnosis of cerebral venous thrombosis (CVT) is possible with the help of computed tomography (CT) scan and magnetic resonance imaging (MRI). Empty Δ sign on postcontrast CT is present in only up to 30% of the cases. The role of CT venography is not yet established, but it is emerging as an effective modality for diagnosis of CVT. T2* MRI sequence is superior to spin echo in detecting CVT and small hemor rhages. MR venography is considered the technique of choice for diagnosis and follow-up of CVT, but in certain cases, MRI could be superior as it shows the thrombus itself and not just the absence of signal as seen on MR venography. Diffusion-weighted imaging is a relatively new MRI technique that is extremely sensitive in detecting acute arterial strokes and can distinguish cytotoxic and vasogenic edema. The presence of hyperintense signal on diffusion-weighted imaging in the occluded veins or sinuses at the time of diagnosis may predict a low rate of vessel recanalization. Contrast angiography should be strongly considered if isolated cortical vein thrombosis is suspected.