engleski

F-18-FET and F-18-choline PET/CT imaging in primary diagnosis of low-grade gliomas with impact on therapy

The aim of this prospective pilot study was to evaluate diagnostic accuracy and impact on therapy of F-18-FET and F-18-FCH in patients with brain lesions suggestive of low-grade gliomas (LGG). Materials and Methods: Eleven patients, 21 to 80 years of age, six of them women, have been included in this pilot study. Initial suspected LGG was reported with 3T magnetic resonance brain imaging. All patients underwent both F-18- FET and F-18-FCH PET/CT brain scan within one week. Brain imaging was performed according to standard protocol 20 minutes after intravenous injection 185 MBq of F-18- FET (O-(2-[F-18]-fluoroethyl)-L- tyrosine) and 185 MBq F-18-FCH (fluoromethyl-(F- 18)-dimethyl-2- hydroxyethylammonium chloride). Biopsy or surgical lesion ablation with the pathohistological diagnosis have been performed in the following month in nine patients, and a year- long clinical follow-up was reported in all patients. Results: Nine patients had a F-18-FET positive lesion, with SUVmax values ranging from 1, 3 to 3, 1. Four patients had F-18- FCH uptake in lesions that were also F-18-FET positive, SUVmax ranging from 0, 5 to 3, 9. Two patients were F-18-FET and F- 18-FCH negative, conventional imaging was suggested in followup. Six patients had surgery and maximal tumour reduction. Histologically, grade IV glioblastoma was reported in two patients, who were both F-18-FET and F-18- FCH positive, with higher SUVmax values of metabolically active brain lesions. Diffuse astrocytoma was reported in four patients, anaplastic astrocytoma in one and two patients had gangliogliomas. Lesions histologically reported as lower grade, also had lower values of SUVmax F-18- FET uptake and were either F-18-FCH negative or had only faint F-18-FCH uptake (SUVmax 0, 5 - 0, 8).In a year-long clinical follow-up period, one patient, negative on both F- 18-FET and F-18-FCH, has no morphological evidence of disease progression, any new therapy, or clinical signs of any brain disorder. One of the patients with aggressive grade IV glioblastoma and the highest SUVmax values of both F-18-FET and F-18-FCH has clinical and morphological progression of the disease. Chemoradiotherapy was included after surgery in five patients, with astrocytoma and glioblastoma histological diagnosis. Conclusion: Preliminary results of this pilot study on a small patient sample suggest functional imaging provides valuable additional information, necessary for individual patient management and further treatment. Amino acid and protein synthesis imaging gives important data on lesion volume and spread, while increased lipid synthesis seems to correlate with higher grade and more aggressive gliomas.

F-18-choline ; glioma ; F-18-FET ; therapy ; histology

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