Reversible MR imaging abnormalities following cerebral venous thrombosis

Abstract

Background and purpose: Although rare, cerebral venous thrombosis (CVT) is being diagnosed more frequently owing to improved imaging techniques. The venous infarcts caused by CVT in 50% of patients are largely reversible and differ from arterial stroke. Our purpose was to study the time-dependent changes of venous infarcts on MR images and to define the variables that influence lesion volume in humans.

Methods: MR images and venous angiograms were evaluated in 15 consecutive patients with venous infarcts due to CVT of sinus, cortical, or internal veins. All patients were treated with intravenous dose-adjusted heparin followed by oral anticoagulation for 12 months. Reduction of signal intensity changes on T1- and T2-weighted images was correlated to the degree of recanalization, age, initial absolute lesion size, and hemorrhage.

Results: Within the first 30 days, we found a significant correlation between the volume of the lesion on T1-weighted images and recanalization. However, early recanalization did not influence the final lesion volume after 12 months. Eleven patients showed complete resolution of changes on T1- and T2-weighted images. Age of the patients influenced initial absolute volume of brain damage.

Conclusion: In venous stroke, even large parenchymal changes can resolve completely independent from recanalization of the thrombosed veins and sinuses. A plausible hypothesis is that venous infarcts largely consist of a persistent edema and that the lesion volume is influenced by the development of collateral veins. However, further investigations are necessary to understand the underlying abnormal mechanisms.

Fig 1.

Time course of the T2 lesion volume reduction in the individual patients.

Fig 2.

Venous cerebellar infarct due to transverse sinus thrombosis in a 56-year-old woman with partial obstruction of the superior sagittal sinus and partial thrombosis of the transverse sinuses. A and B, T2-weighted MR image (A) and 3D time-of-flight MR angiogram (B) obtained on admission show the venous cerebellar infarct and transverse sinus thrombosis, respectively. C and D, Follow-up MR images obtained after 6 months. Despite persistent partial obstruction of the transverse sinus (D), near complete resolution is noted of the volume of the T2 lesion (C).

Fig 3.

Venous temporal infarct in a 37-year-old woman. A and B, T2-weighted MR image (A) and 3D time-of-flight MR angiogram (B) obtained on admission show a venous infarct in the temporal lobe due to thrombosis of the transverse sinus. Thrombosis of the superior sagittal sinus caused no infarct. C–E, Follow-up MR images obtained after 12 months show that despite persistent occlusion of the transverse sinus (D and E) and only partial recanalization of the superior sagittal sinus, the volume of the venous infarct decreased substantially (C) at follow-up.

Fig 4.

Venous infarct in the temporo-occipital region in a 43-year-old woman. A and B, T2-weighted MR image (A) and 3D time-of-flight MR angiogram (B) obtained on admission. The MR angiogram shows a thrombosis of the transverse sinus. C and D, Follow-up MR images obtained after 3 months show total resolution of the parenchymal lesion (C) despite persistent occlusion of the transverse sinus (D).

Fig 5.

Venous infarct due to cortical vein thrombosis in a 27-year-old woman. A, T2-weighted MR image obtained on admission shows the venous infarct due to cortical vein thrombosis. B, Conventional angiography on admission shows a right parietal cortical vein thrombosis. C, Follow-up T2-weighted MR image obtained after 3 months shows total resolution of the initial lesion. In this case, no analysis regarding recanalization was performed.

Fig 6.

Hemorrhagic venous infarct due to thrombosis of the superior sagittal sinus in a 66-year-old man. A and B, T2-weighted MR image (A) and MR angiogram (B) show a parenchymal lesion due to a superior sagittal sinus thrombosis. The patient also had a second infarct (not shown). C and D, Follow-up MR images show recanalization of the superior sagittal sinus (D) and decrease of total lesion volume by 74% (C).