18F-FET PET Differentiation of Ring-Enhancing Brain Lesions

Journal of Nuclear Medicine

Frank W. Floeth¹  Kurt Hamacher¹  Karl-Josef Langen¹  Gabriele Stoffels¹  Frank Rommel¹  Dirk Pauleit¹  Walter Stummer¹  Guido Reifenberger¹  Michael Sabel¹ 

关键词: ring enhancement;    ¹⁸F-FET PET;    abscess;    glioblastoma;   

DOI  :  

学科分类：医学（综合）

来源: Society of Nuclear Medicine

【 摘 要 】

The aim of this study was to explore the differential diagnostic value of PET using the amino acid O-(2-18F-fluoroethyl)-l-tyrosine (18F-FET) in patients with newly diagnosed solitary intracerebral lesions showing ring enhancement on contrast-enhanced MRI. Methods: 18F-FET PET analyses were performed on 14 consecutive patients with intracerebral ring-enhancing lesions. Eleven of the patients were additionally studied with 18F-FDG PET. In all patients, the main differential diagnosis after MRI was a malignant lesion, in particular glioblastoma multiforme, versus a benign lesion, in particular brain abscess. A malignant tumor was suspected for lesions showing increased 18F-FET uptake on PET images with a mean lesion-to-brain ratio of at least 1.6 (18F-FET PET positive). A nonneoplastic lesion was suspected in cases of minimal or absent 18F-FET uptake, with a mean lesion-to-brain ratio of less than 1.6 (18F-FET PET negative). Histologic diagnosis was obtained by serial biopsies in 13 of the 14 patients. One patient refused the biopsy, but follow-up indicated an abscess because his lesion regressed under antibiotic therapy. Results: Histology and clinical follow-up showed high-grade malignant gliomas in 5 patients and nonneoplastic lesions in 9 patients. The findings of 18F-FET PET were positive in all 5 glioma patients and in 3 of 9 patients with nonneoplastic lesions, including 2 patients with brain abscesses and 1 patient with a demyelinating lesion. The findings of 18F-FDG PET were positive (mean lesion-to-gray matter ratio ≥ 0.7) in 4 of 4 glioma patients and 3 of 7 patients with nonneoplastic lesions. Conclusion: Although 18F-FET PET has been shown to be valuable for the diagnostic evaluation of brain tumors, our data indicate that, like 18F-FDG PET, 18F-FET PET has limited specificity in distinguishing between neoplastic and nonneoplastic ring-enhancing intracerebral lesions. Thus, histologic investigation of biopsy specimens remains mandatory to make this important differential diagnosis.

【 授权许可】

Unknown