Artikel
Can intraoperative MRI replace 5-ALA in brain tumor surgery?
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Veröffentlicht: | 4. Juni 2012 |
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Gliederung
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Objective: Recent evidence suggests that the extent of resection (EOR) is a prognosticator for patients harboring gliomas. The use of both, intraoperative MRI- (iMRI) and 5-aminolevulinic acid (5-ALA) has been proven to improve the extent of resection in glioma surgery. Our aim was to compare iMRI with 5-ALA fluorescence-guidance in order to maximize EOR.
Methods: 25 patients with known or suspected high-grade gliomas undergoing intended gross total resection (GTR) were included in a prospective study. All patients received 20 mg / kg 5-ALA prior to surgery. When GTR was thought to be achieved, an iMRI scan was performed, and blue light turned on, to search for unintentionally remaining tumor tissue. IMRI findings were directly compared with intraoperative fluorescence findings in every patient. Histological examinations of the bulk of the tumor as well as any additionally resected tissue were performed and classified as normal tissue, infiltration zone, or solid tumor. All patients underwent early postoperative high-field MRI to determine EOR.
Results: Postoperative MRI showed GTR in all patients. In 10 patients (40%), iMRI and fluorescence unequivocally had not shown residual tumor intraoperatively. In 15 patients (60%) resection was continued due to iMRI and/or fluorescence findings. In 10 out of these (66.7%), iMRI and 5-ALA findings were inconsistent regarding residual tumor. Histological examination ruled out false positive findings in all additionally resected specimens. Sensitivity and specificity to detect residual tumor tissue were 66.7% and 100%, respectively, for both iMRI and 5-ALA. The accuracy of these surgical tools to detect residual tumor was 80.0% each. The majority of additionally resected specimens due to iMRI findings were classified as solid tumor, while they represented infiltration zone more often than solid tumor in specimens additionally resected due to 5-ALA findings. Complications occurred in 3 patients (12%) and were not attributable to continued resection (P = 0.25).
Conclusions: IMRI and 5-ALA are complementary techniques in brain tumor surgery. Although iMRI detected residual solid tumor more frequently than 5-ALA, optimum results can only be achieved through combined use of these surgical tools.