Dynamic O-(2-[18F]fluoroethyl)-L-tyrosine (F-18 FET) PET for Glioma Grading: Assessment of Individual Probability of Malignancy

• Published in: Clinical nuclear medicine 2011-10, Vol.36 (10), p.841-847
• Main Authors: Calcagni, Maria Lucia, Galli, Guido, Giordano, Alessandro, Taralli, Silvia, Anile, Carmelo, Niesen, Andreas, Baum, Richard Paul
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Brain Neoplasms - diagnostic imaging; Brain Neoplasms - pathology; Female; Glioma - diagnostic imaging; Glioma - pathology; Humans; Male; Middle Aged; Neoplasm Grading; Positron-Emission Tomography; Time Factors; Tyrosine - analogs & derivatives; Tyrosine - pharmacokinetics; Young Adult
• ISSN: 0363-9762; 1536-0229
• DOI: 10.1097/RLU.0b013e3182291b40

PURPOSE:(1) To investigate the diagnostic value of some O-(2-[F]fluoroethyl)-L-tyrosine (F-18 FET) indices derived from the dynamic acquisition to differentiate low-grade gliomas from high-grade; (2) to analyze the course of tumor time-activity curves (TACs); and (3) to calculate the individual probability of a high-grade glioma using the logistic regression. METHODS:Seventeen low-grade (WHO I–II) and 15 high-grade (WHO III–IV) gliomas were studied with dynamic F-18 FET PET. Regions of interests were drawn over the tumor and contralateral brain, and TACs were analyzed. We considered early standardized uptake value (SUV), middle SUV, late SUV, early-to-middle SUV tumor ratio, early-to-late SUV tumor ratio; time to peak (Tpeak), in minutes, from the beginning of the dynamic acquisition up to the maximum SUV of the tumor; and SoD (sum of the frame-to-frame differences). To assess the individual probability of high-grade, logistic regression was also used. RESULTS:High-grade gliomas showed significantly (P < 0.0001) higher values when compared with low-grade gliomas in early SUV, early-to-middle ratio, early-to-late ratio, Tpeak, and SoD. For the grading of gliomas, the best indices were early-to-middle ratio and Tpeak providing a diagnostic accuracy of 94%. TACs analysis provided an 87% diagnostic accuracy. For individual high-grade diagnosis, the logistic regression provided 93% sensitivity, 100% specificity, and 97% accuracy. CONCLUSION:Early-to-middle SUV tumor ratio and Tpeak were the best indices for assessing the grading of gliomas. Since early-to-middle ratio derives from the first 35 minutes of the dynamic acquisition, the PET study could last half an hour instead of 1 hour. By logistic regression, it is possible to assess the individual probability of high-grade, useful for prognosis and treatment.