Low-Grade Versus High-Grade Glioma That Is the Question. 18F-Fluorocholine PET in the Detection of Anaplastic Focus.

Gliomas are characterized by intratumoral histological heterogeneity, coexisting foci of low and high grade. First, in low-grade gliomas, neoangiogenesis has not yet developed and cellularity is low, so alterations on perfusion MRI may not be present. Second, a non-negligible number of high-grade gliomas show none, patchy, or weak contrast enhancement on MRI, so they can be misdiagnosed as low-grade glioma, preventing their correct management. We present 4 cases of patients in which F-fluorocholine PET defined the anaplastic tumor component and therefore the tumor aggressiveness, solving the limitations of MRI.

Metabolic targeting can improve the efficiency of brain tumor biopsies.

Brain tumors comprise a heterogeneous group of diseases, featuring different biology, prognosis, and treatment. The most known forms are malignant gliomas and metastases. Brain biopsy is a recognized technique in the management of intracranial space-occupying lesions and tumors in particular. Tumor heterogeneity of malignant brain lesions has been described and can lead to significant sampling errors in stereotactic biopsy. Different methods have been used to perform biopsies, including biopsy guided by CT or RMI, echoguided or stereotactic. The choice of the target with the help of PET and MRI with spectroscopy allows one to identify metabolically more active areas of the tumor, and in this way reduce the rate of negative results.

18F-Fluorocholine PET/CT in the Prediction of Molecular Subtypes and Prognosis for Gliomas.

AIM: To study the association of metabolic features of F-fluorocholine in gliomas with histopathological and molecular parameters, progression-free survival (PFS) and overall survival (OS). METHODS: Prospective multicenter and nonrandomized study (Functional and Metabolic Glioma Analysis). Patients underwent a basal F-fluorocholine PET/CT and were included after histological confirmation of glioma. Histological and molecular profile was assessed: grade, Ki-67, isocitrate dehydrogenase status and 1p/19q codeletion. Patients underwent standard treatment after surgery or biopsy, depending on their clinical situation. Overall survival and PFS were obtained after follow-up. After tumor segmentation of PET images, SUV and volume-based variables, sphericity, surface, coefficient of variation, and multilesionality were obtained. Relations of metabolic variables with histological, molecular profile and prognosis were evaluated using Pearson χ and t test. Receiver operator caracteristic curves were used to obtain the cutoff of PET variables. Survival analysis was performed using Kaplan-Meier and Cox regression analysis. RESULTS: Forty-five patients were assessed; 38 were diagnosed as having high-grade gliomas. Significant differences of SUV-based variables with isocitrate dehydrogenase status, tumor grade, and Ki-67 were found. Tumor grade, Ki-67, SUVmax, and SUVmean were related to progression. Kaplan-Meier analysis revealed significant associations of SUVmax, SUVmean, and multilesionaly with OS and PFS. SUVmean, sphericity, and multilesionality were independent predictors of OS and PFS in Cox regression analysis. CONCLUSIONS: Metabolic information obtained from F-fluorocholine PET of patients with glioma may be useful in the prediction of tumor biology and patient prognosis.

18F-Fluorocholine PET/CT, Brain MRI, and 5-Aminolevulinic Acid for the Assessment of Tumor Resection in High-Grade Glioma.

High-grade glioma is a very aggressive and infiltrative tumor in which complete resection is a chance for a better outcome. We present the case of a 57-year-old man with a brain lesion suggestive of high-grade glioma. Brain MRI and F-fluorocholine PET/CT were performed previously to plan the surgery. Surgery was microscope assisted after the administration of 5-aminolevulinic acid. Postsurgery brain MRI and PET were blind evaluated to the surgery results and reported as probably gross total resection.