Preoperative evaluation of venous systems with computed tomography venography in parasagittal meningiomas.

OBJECTIVE: Parasagittal meningiomas (PSM) may pose a difficult surgical challenge because venous patency and collateral anastomoses have to be clearly defined for correct surgical planning. The aim of this study was to study the diagnostic accuracy of computed tomography venography (CTV) in assessing the superior sagittal sinus (SSS) obstruction and venous collaterals.

METHODS: Twenty-four patients undergoing surgery for meningiomas located adjacent to the SSS were prospectively evaluated. All the patients underwent both conventional computed tomography examination and CTV. Computed tomography venography was evaluated by 2 expert neuroradiologists to assess (1) patency of the sinus (patent/occluded), (2) the extent of occlusion (in centimeters), and (3) the number of collateral anastomoses close to the insertion of the meningioma. Computed tomography venography assessment was compared with surgery. All patients were operated on, and intraoperative findings were taken as the criterion standard.

RESULTS: Computed tomography venography showed the sinus to be occluded in 6 cases. Computed tomography venography data were confirmed by surgery, showing 6 patients to have have an occlusion of the SSS. The CTV sensitivity was thus 100%. Computed tomography venography depicted 83% of collateral venous anastomoses close to the meningioma as subsequently confirmed by surgery.

CONCLUSIONS: In the preoperative planning for patients with meningiomas located close to the SSS, CTV can provide additional and more reliable information concerning venous infiltration and the presence of collateral anastomoses compared with noncontrast computed tomography.