title: The Sum of Tumour-to-Brain Ratios Improves the Accuracy of Diagnosing Gliomas Using 18F-FET PET.
abstract: Gliomas are common brain tumours, but obtaining tissue for definitive diagnosis can be difficult. There is, therefore, interest in the use of non-invasive methods to diagnose and grade the disease. Although positron emission tomography (PET) with 18F-fluorethyltyrosine (18F-FET) can be used to differentiate between low-grade (LGG) and high-grade (HGG) gliomas, the optimal parameters to measure and their cut-points have yet to be established. We therefore assessed the value of single and dual time-point acquisition of 18F-FET PET parameters to differentiate between primary LGGs (n = 22) and HGGs (n = 24). PET examination was considered positive for glioma if the metabolic activity was 1.6-times higher than that of background (contralateral) brain, and maximum tissue-brain ratios (TBRmax) were calculated 10 and 60 min after isotope administration with their sums and differences calculated from individual time-point values. Using a threshold-based method, the overall sensitivity of PET was 97%. Several analysed parameters were significantly different between LGGs and HGGs. However, in a receiver operating characteristics analysis, TBR sum had the best diagnostic accuracy of 87% and sensitivity, specificity, and positive and negative predictive values of 100%, 72.7%, 80%, and 100%, respectively. 18F-FET PET is valuable for the non-invasive determination of glioma grade, especially when dual time-point metrics are used. TBR sum shows the greatest accuracy, sensitivity, and negative predictive value for tumour grade differentiation and is a simple method to implement. However, the cut-off may differ between institutions and calibration strategies would be useful.
authors.affiliation: Department of Positron Emission Tomography and Molecular Imaging, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum, Bydgoszcz, Poland; Department of Nuclear Medicine, Franciszek Lukaszczyk Oncology Centre, Bydgoszcz, Poland.
authors.forename: Bogdan
authors.initials: B
authors.lastname: Malkowski
authors.affiliation: Department of Radiotherapy, Franciszek Lukaszczyk Oncology Centre, Bydgoszcz, Poland; Department of Oncology and Brachytherapy, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum, Bydgoszcz, Poland.
authors.forename: Maciej
authors.initials: M
authors.lastname: Harat
authors.affiliation: Department of Radiotherapy, Franciszek Lukaszczyk Oncology Centre, Bydgoszcz, Poland; Department of Oncology and Brachytherapy, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum, Bydgoszcz, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Zyromska
authors.affiliation: Department of Radiotherapy, Franciszek Lukaszczyk Oncology Centre, Bydgoszcz, Poland; Department of Oncology and Brachytherapy, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum, Bydgoszcz, Poland.
authors.forename: Tomasz
authors.initials: T
authors.lastname: Wisniewski
authors.affiliation: Department of Public Health, Nicolaus Copernicus University, Ludwik Rydygier Collegium Medicum, Bydgoszcz, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Harat
authors.affiliation: Department of Nuclear Medicine, Franciszek Lukaszczyk Oncology Centre, Bydgoszcz, Poland.
authors.forename: Rita
authors.initials: R
authors.lastname: Lopatto
authors.affiliation: Department of Neurosurgery, 10th Military Research Hospital and Polyclinic, Bydgoszcz, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Furtak
mesh_terms: D000328:Adult; D000368:Aged; D001706:Biopsy; D001932:Brain Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D005910:Glioma / Q000000981:diagnostic imaging* / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D049268:Positron-Emission Tomography / Q000379:methods / Q000592:standards; D012372:ROC Curve; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D047368:Tumor Burden; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals