(18)F-Fluoroethyl-l-Thyrosine Positron Emission Tomography to Delineate Tumor Residuals After Glioblastoma Resection: A Comparison with Standard Postoperative Magnetic Resonance Imaging.

Complete resection of contrast-enhancing tumor is an important prognostic factor in glioblastoma therapy. The current clinical standard for control of resection is magnetic resonance imaging (MRI). (18)F-Fluoroethyl-l-thyrosine (FET) is a positron emission tomography (PET) radiopharmaceutical applicable for widespread use because of its long half-life radionuclide. We assessed the sensitivity of postoperative MRI versus FET-PET to detect residual tumor and the impact of the time interval between resection and FET-PET.MRI and FET-PET were performed preoperatively and postoperatively in 62 patients undergoing 63 operations. FET-PET was performed in 43 cases within 72 hours after resection and in 20 cases >72 hours after resection. Detection and measurement of volume of residual tumors were compared. Correlations between residual tumor detection and timing of PET after resection and recurrence were examined.Complete resection was confirmed by both imaging modalities in 44% of cases, and residual tumor was detected consistently in 37% of cases. FET-PET detected residual tumor in 14% of cases in which MRI showed no residual tumor. MRI showed residual tumors in 5% of cases that were not identified by PET. Average PET-based residual tumor volume was higher than MRI-based volume (3.99 cm(3) vs. 1.59 cm(3)). Detection of and difference in volume of residual tumor were not correlated with timing of PET after resection or recurrence status.Postoperative FET-PET revealed residual tumor with higher sensitivity than MRI and showed larger tumor volumes. In this series, performing PET >72 hours after resection did not influence the results of PET. We recommend FET-PET as a helpful adjunct in addition to MRI for postoperative assessment of residual tumor.     «

Complete resection of contrast-enhancing tumor is an important prognostic factor in glioblastoma therapy. The current clinical standard for control of resection is magnetic resonance imaging (MRI). (18)F-Fluoroethyl-l-thyrosine (FET) is a positron emission tomography (PET) radiopharmaceutical applicable for widespread use because of its long half-life radionuclide. We assessed the sensitivity of postoperative MRI versus FET-PET to detect residual tumor and the impact of the time interval between...     »