[Imaging for the management of cavernous sinus meningiomas]

Cavernous sinus meningiomas: imaging and surgical strategy

Cavernous sinus (CS) meningiomas which are by definition those meningiomas which originate from the parasellar region are difficult skull base tumors to deal with. For deciding the most appropriate surgical strategy, surgeons need detailed preoperative neuroimaging. The vicinity of the tumor with the vital and highly functional neurovascular structures, tumor extensions into the basal cisterns and skull base structures, and the arterial vascularization and venous drainage pathways, as they shape operative strategy, are important preoperative data to take into account. Thin section CT scan with bone windows, 3D spiral CT reconstruction, MRI, MR angiography, and DSA performed with selective arteriography including late venous phases give those required detailed informations about the tumor and its relation with neurovascular and bony structures. The type of craniotomy and complementary osteotomy and the usefulness of an extradural anterior clinoidectomy with unroofing the optic canal can be decided from preoperative neuroimaging. Data collected also help in determining whether extensive exposure of the middle cranial fossa is necessary to ensure substantial devascularization of the tumor and whether proximal control of the internal carotid artery (ICA) at its intrapetrosal portion might be useful. Study of the capacity of blood supply of the Willis circle is wise for deciding the need and way of performing an extra-intracranial bypass together with tumor removal. Currently the concept of operating only the tumors with extracavernous extensions and to limit resection to only their extracavernous portions is the most accepted way of treating these tumors. It was that strategy that was adopted in the senior author's 220-patient series.Radiosurgery or stereotactic fractionated radiotherapy may complement surgery or can be only reserved for growing remnants.

No more fear of the cavernous sinuses!

After a review of the anatomy of the cavernous sinuses (CS), this work presents the clinical picture and imaging protocol of lesions which occur in this area. It outlines extension and imaging features of these lesions. It emphasises MRI appearance, such as T1, T2 and diffusion signal, type of contrast medium uptake. A complementary CT scan is performed if an associated abnormality of the base of the skull is suspected on MRI (lysis, condensation). This paper proposes a straightforward classification system depending on imaging and sets out the principal symptoms of the main aetiologies of CS lesions which are represented by various diseases such as tumours, inflammations, vascular abnormalities. Complementary to imaging, their diagnosis is based on clinical data i.e. known cancer, signs suggesting inflammation. Its rich iconography allows this article to be used as a reference in current clinical practice.