Comparison of 18F-FET PET and Perfusion-Weighted MR Imaging: A PET/MR Imaging Hybrid Study in Patients with Brain Tumors

Journal of Nuclear Medicine

Hans Herzog¹  Heinz H. Coenen¹  Hans J. Wittsack¹  Bernd Turowski¹  Christian P. Filss¹  Gereon R. Fink¹  Gerald Antoch¹  Ke Zhang¹  Michael Sabel¹  Norbert Galldiks¹  Karl-Josef Langen¹  Gabriele Stoffels¹  Nadim J. Shah¹ 

关键词: PET/MR imaging;    glioma;    O-(2-¹⁸F-fluoroethyl)-l-tyrosine;    PWI;    rCBV;    histogram;   

DOI  :  10.2967/jnumed.113.129007

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

PET using O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) provides important diagnostic information in addition to that from conventional MR imaging on tumor extent and activity of cerebral gliomas. Recent studies suggest that perfusion-weighted MR imaging (PWI), especially maps of regional cerebral blood volume (rCBV), may provide similar diagnostic information. In this study, we directly compared 18F-FET PET and PWI in patients with brain tumors. Methods: Fifty-six patients with gliomas were investigated using static 18F-FET PET and PWI. For comparison, 8 patients with meningiomas were included. We generated a set of tumor and reference volumes of interest (VOIs) based on morphologic MR imaging and transferred these VOIs to the corresponding 18F-FET PET scans and PWI maps. From these VOIs, tumor-to-brain ratios (TBR) were calculated, and normalized histograms were generated for 18F-FET PET and rCBV maps. Furthermore, in rCBV maps and in 18F-FET PET scans, tumor volumes, their spatial congruence, and the distance between the local hot spots were assessed. Results: For patients with glioma, TBR was significantly higher in 18F-FET PET than in rCBV maps (TBR, 2.28 ± 0.99 vs. 1.62 ± 1.13; P < 0.001). Histogram analysis of the VOIs revealed that 18F-FET scans could clearly separate tumor from background. In contrast, deriving this information from rCBV maps was difficult. Tumor volumes were significantly larger in 18F-FET PET than in rCBV maps (tumor volume, 24.3 ± 26.5 cm3 vs. 8.9 ± 13.9 cm3; P < 0.001). Accordingly, spatial overlap of both imaging parameters was poor (congruence, 11.0%), and mean distance between the local hot spots was 25.4 ± 16.1 mm. In meningioma patients, TBR was higher in rCBV maps than in 18F-FET PET (TBR, 5.33 ± 2.63 vs. 2.37 ± 0.32; P < 0.001) whereas tumor volumes were comparable. Conclusion: In patients with cerebral glioma, tumor imaging with 18F-FET PET and rCBV yields different information. 18F-FET PET shows considerably higher TBRs and larger tumor volumes than rCBV maps. The spatial congruence of both parameters is poor. The locations of the local hot spots differ considerably. Taken together, our data show that metabolically active tumor tissue of gliomas as depicted by amino acid PET is not reflected by rCBV as measured with PWI.

【 授权许可】

Unknown