Progress in the diagnosis and treatment of patients with meningiomas. Part I: diagnostic imaging, preoperative embolization.

BACKGROUND: The clinical management of patients with meningiomas has changed over the past decade. Change has occurred because of a variety of factors including improved diagnostic imaging, better results with surgery and interventional neuroradiology, and the advent of radiosurgery. Recent clinical studies from several disciplines have provided new information on topics germane to the management of patients with meningiomas. Collecting this information into a series of review articles would have significant value, primarily for neurosurgeons.
OBJECTIVE: The purpose of this first paper is to bring together and evaluate the available data on: 1) noninvasive diagnostic imaging of meningiomas, including magnetic resonance imaging (MRI), computed tomography (CT) scanning, and MR angiography, venography and spectroscopy; 2) the present role of cerebral angiography in patients with meningiomas; and 3) the current status of preoperative embolization for these tumors.
RESULTS: With the advent of MR technology, the quality of diagnostic imaging for meningiomas has improved dramatically, and this is reflected in more sophisticated preoperative planning. MR imaging provides improved delineation of dura and sinus involvement, and even information about a tumor's consistency. Meningiomas have characteristic neuroimaging features, yet other lesions can still mimic a meningioma. MR venography can be used to demonstrate sinus patency, but intra-arterial cerebral angiography gives the most precise information concerning the degree of tumor involvement of critical vascular structures, and the anatomy of arterial feeders. In trained hands, superselective catheterization for preoperative embolization of meningiomas is feasible, and seems to be reasonably safe.
CONCLUSIONS: MR imaging, CT scans, and cerebral angiography can currently be used in a complementary fashion to diagnose, evaluate, and treat patients with meningiomas, with a high degree of clinical certainty. Angiography is used to determine the sites of blood supply to the tumor, which can then be attacked first intraoperatively, making tumor removal easier. Preoperative embolization continues to have value in selected patients, including those in whom the blood supply to the tumor is difficult to access at the time of surgery.