gms | German Medical Science

Objective: To evaluate the integration of Positron Emission Tomography (PET) images into the image-guided resection of low-grade gliomas.

Methods: PET images using [¹⁸F]fluorodeoxyglucose and [¹¹C]methionine were combined to magnetic resonance (MR) images in the navigation planning of 103 navigation procedures for low-grade gliomas. These procedures were performed in 91 patients (57M/34F) in which ill-defined tumour boundaries could not be clearly identified for image-guided resection. Level and distribution of PET tracer uptake were analyzed to define a PET contour, projected on MR images to define a final target contour for volumetric resection (displayed in the microscope). Maximal tumour resection was accomplished in each case, with the intention to remove the entire abnormal metabolic area comprised in the surgical planning. Early postoperative MR and PET assessed the quality of tumour resection. Survival analysis compared patients with total and subtotal/partial resection of PET tracer uptake.

Results: Metabolic information on tumour heterogeneity or distribution were useful for planning the surgery. In 83/103 procedures (80%), PET improved tumor delineation and contributed to define a final target contour different from that obtained with MR alone. Total resection of the increased PET tracer uptake was achieved in 54/103 (52%) procedures and provided a longer survival (p=0,007) compared to patients with postoperative residual PET tracer uptake.

Conclusions: PET-guidance helps to increase the amount of tumor removed and to target image-guided resection to tumour portions, which present the highest evolving potential. A complete resection of the increased PET tracer uptake might increase the patient’s survival.