In the vast majority of studies that address the role of surgery in the management of high-grade gliomas, the degree of tumor removal accomplished is solely based on the intraoperative perception of the neurosurgeon. Despite its fundamental importance for a comparison of different treatment modalities, little systematic effort has been made to evaluate the residual gross tumor by neuroimaging methods immediately after surgery. We report the results of a prospective study using contrast-enhanced computed tomography and magnetic resonance imaging (MRI) to monitor 60 patients after the resection of a high-grade glioma. In each case, the first scans were obtained between Days 1 and 5 after surgery, followed by serial imaging every 2 to 3 months, usually until the condition of the patient deteriorated severely or the patient died. Gadolinium-enhanced MRI proved to be extremely valuable for assessing gross residual tumor when performed during Days 1 to 3 after the resection of a preoperatively enhancing high-grade glioma. This timing avoided surgically induced contrast enhancement and minimized interpretative difficulties. In delineating residual tumor, MRI was vastly superior to computed tomography. About 80% of tumor "recurrences" emerged from definitely enhancing remnants, as revealed by early postoperative MRI. The neurosurgeon's estimation of gross tumor burden reduction could be shown to be much less accurate (by a factor of 3) than the postoperative assessment by modern neuroimaging. In our series, residual tumor enhancement was the most predictive prognostic factor of survival in patients with glioblastoma, followed by radiotherapy. Patients with a residual tumor postoperatively had a 6.595-times higher risk of death in comparison to patients without a residual tumor. Patients undergoing radiotherapy had a 0.258-times lower risk of death in comparison to patients who were not treated with radiation. Concerning survival, the prognostic significance of both variables surpassed age and performance.

These results indicate a correlation between radiation and cavernoma, particularly in children under 10 years of age at the time of radiation therapy. In adults, cavernomas after radiation rarely occur, and then only after higher radiation dosages (3000 cGy or more).

We describe four patients with intraosseous cavernous hemangiomas of the skull which were localized supraorbitally, parietally (two cases), and occipitally. The diameter ranged from 15 mm to 25 mm. They presented with slowly growing mass, tender to pressure, with spontaneous pain, and with freely mobile skin above the cavernoma sites. Magnetic resonance imaging (hyperintensity on T2 and isointensity with brain on T1) and CT (osteolytic lesion with erosion of the tabula externa) confirmed the plain skull films showing the honeycomb or sunburst appearance pattern. Resections and postoperative course were uneventful. In three of these cases there was coexistence with tumors (meningeoma, malignant lymphoma, and malignant melanoma); none of these constellations has been described before. Generally, cavernous hemangiomas of the skull are rare. There is one extensive review published by Barnes in 1984 regarding a period of 136 years with 123 intraosseous hemangiomas of the skull and 74 of the jaws. Unfortunately, the histological confirmation is not completely clear and some capillary hemangiomas are included. In a review of the literature since 1975, we found 103 histologically proven intraosseous cavernous hemangiomas of the skull (with our four cases included) and 22 of the jaws, which are shown in an overview with respect to their localization. The most frequent site was frontal, followed by temporal.

Intraoperative MRI is safe and allows reliable updating of neuronavigational data, with compensation for brain shifting. Surgically induced imaging changes, which have been identified as a possible problem with intraoperative MRI in general, necessitated comparisons with preoperative scans and require future attention. The extent of tumor removal and survival times were increased significantly. Overall, patients seemed to benefit from the method.