Abstract
This review by Pham Thi Ngoc Linh and Vo Hong Khoi describes the MRI and MR venography (MRV) findings in cerebral venous thrombosis (CVT), a rare stroke subtype accounting for 0.5-1% of all strokes, with an annual incidence of 5 per 1,000,000 population and predominantly affecting young adults (78% under age 50). Parenchymal changes in CVT include vasogenic edema (distinct from cytotoxic edema seen in arterial ischemic stroke, distinguishable via DWI/ADC patterns), venous infarction (characterized by multifocal, non-arterial territory lesions with subcortical involvement and unclear margins corresponding to venous drainage territories), and parenchymal hemorrhage (occurring in up to one-third of cases, best detected with T2* sequences). Deep cerebral venous thrombosis (16% of cases) typically produces bilateral thalamic edema, while isolated cortical vein thrombosis (2-5% of cases) is best identified via GRE T2* sequences showing exaggerated susceptibility signal loss. Thrombus signal characteristics evolve through distinct temporal stages: hyperacute (1-5 days, isointense on T1W, hypointense on T2W due to oxyhemoglobin), subacute (days 6-21, progressively hyperintense on T1W then T2W due to methemoglobin conversion), and chronic (beyond 21-35 days, heterogeneous signal, potentially mimicking recurrent thrombosis). For venous sinus imaging, two MRV techniques are employed: 2D time-of-flight (TOF) MRV, which is fast and flow-sensitive but cannot reliably distinguish thrombosis from sinus hypoplasia/aplasia and is less sensitive for isolated cortical vein thrombosis; and contrast-enhanced 3D T1-weighted MRV, considered comparable to digital subtraction angiography (DSA) and superior to TOF for evaluating normal venous anatomy, though susceptible to false-negative results during chronic thrombosis with recanalization.
