PT - JOURNAL ARTICLE AU - Frank W. Floeth AU - Dirk Pauleit AU - Michael Sabel AU - Gabriele Stoffels AU - Guido Reifenberger AU - Markus J. Riemenschneider AU - Paul Jansen AU - Heinz H. Coenen AU - Hans-Jakob Steiger AU - Karl-Josef Langen TI - Prognostic Value of <em>O-</em>(2-<sup>18</sup>F-Fluoroethyl)-<span class="sc">l</span>-Tyrosine PET and MRI in Low-Grade Glioma AID - 10.2967/jnumed.106.037895 DP - 2007 Apr 01 TA - Journal of Nuclear Medicine PG - 519--527 VI - 48 IP - 4 4099 - http://jnm.snmjournals.org/content/48/4/519.short 4100 - http://jnm.snmjournals.org/content/48/4/519.full SO - J Nucl Med2007 Apr 01; 48 AB - In glioma of World Health Organization (WHO) grade II (low-grade glioma), the natural course of a particular patient is not predictable and the treatment strategy is controversial. We determined prognostic factors in adult patients with untreated, nonenhancing, supratentorial low-grade glioma with special regard to PET using the amino acid O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) and MRI. Methods: In a prospective study, baseline 18F-FET PET and MRI analyses were performed on 33 consecutive patients with histologically confirmed low-grade glioma. None of the patients had radiation or chemotherapy. Clinical, histologic, therapeutic (initial cytoreduction vs. biopsy), 18F-FET uptake, and MRI morphologic parameters were analyzed for their prognostic significance. Statistical endpoints were clinical or radiologic tumor progression, malignant transformation to glioma of WHO grade III or IV (high-grade glioma), and death. Results: Baseline 18F-FET uptake and a diffuse versus circumscribed tumor pattern on MRI were highly significant predictors of prognosis (P &lt; 0.01). By the combination of these prognostically significant variables, 3 major prognostic subgroups of low-grade glioma patients could be identified. The first of these subgroups was patients with circumscribed low-grade glioma on MRI without 18F-FET uptake (n = 11 patients, progression in 18%, no malignant transformation and no death). The second subgroup was patients with circumscribed low-grade glioma with 18F-FET uptake (n = 13 patients, progression in 46%, malignant transformation to a high-grade glioma in 15%, and death in 8%). The third subgroup was patients with diffuse low-grade glioma with 18F-FET uptake (n = 9 patients, progression in 100%, malignant transformation to a high-grade glioma in 78%, and death in 56%). Conclusion: We conclude that baseline amino acid uptake on 18F-FET PET and a diffuse versus circumscribed tumor pattern on MRI are strong predictors for the outcome of patients with low-grade glioma.