Early Postoperative Magnetic Resonance Imaging after Resection of Malignant Glioma: Objective Evaluation of Residual Tumor and Its Influence on Regrowth and Prognosis

Abstract

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.

Revisiting anaplastic astrocytomas I: An expansive growth pattern is associated with a better prognosis

“…This has been shown in previous studies to be significant for anaplastic astrocytoma survival (11,16,(35)(36)(37). Our review also reflected comparable aggressive resections in 10 of 34 EAA cases vs. NEAA cases (9 of 25) and 8 of 31 mixed/infiltrative tumors vs. expansive tumors (11 of 28) ( Table 1).…”

“…MRI scans were obtained within 72 h of craniotomy to assess any residual area of contrast enhancement (16). Although NEAA preoperatively, gadolinium was routinely administered for postoperative NEAA patients as well.…”

Detection of Tumor Progression by Signal Intensity Increase on Fluid-Attenuated Inversion Recovery Magnetic Resonance Images in the Resection Cavity of High-Grade Gliomas

“…9) Also, 80% of glioma recurrences emerged from areas of enhancement at MR imaging. 1) In fact, the resection cavities in our cases had wide contact with tumor tissues, and all tumor progression occurred close to the original tumor bed in the cases with SI increase. If infiltration of the neoplastic cells in the cavity wall occurred before SI increase, this should be reflected in changes in diffusion-weighted images and apparent diffusion coefficient, but this MR sequence was not performed in the present study.…”

Motor Homunculus: Passive Mapping in Healthy Volunteers by Using Functional MR Imaging—Initial Results

“…One key to prolonged survival is cytoreductive excision of the brain tumor (23)(24)(25), generally used in conjunction with radiation and chemotherapy. Surgery alone can be associated with neurologic dysfunction in up to 25% of patients (26)(27)(28).…”