Abstract
1296
Purpose: To identify the role of 11C-methionine (11C-MET) PET and proton MR spectroscopy (1H-MRS) in diagnosing clinically suspected gliomas and to assess the combined diagnostic value of 11C-MET PET and 1H-MRS in gliomas.
Methods: A total of 48 patients (female 17, male 31, mean age ± SD, 43 ± 15 y) with clinically suspected glioma were enrolled in this retrospective study. The participants underwent 11C-MET PET/CT and 1H-MRS within a month. 11C-MET PET/CT Semiquantitative-parameters of the maximum lesion-to-normal ratio (LNRmax) and 1H-MRS data of ratio of choline to N-acetyl-aspartate (Cho/NAA) were applied in differentiating gliomas from non-neoplastic lesions (NNLs) and glioma WHO grade. 1H-MRS was considered as tumor if the Cho/NAA ratio was greater than 1.
Results: There were 21 low-grade gliomas (LGGs), 14 high-grade gliomas (HGGs) among gliomas. And NNLs included 7 cases of demyelination, 2 cases of hemorrhagic necrosis, 1 cases of parasitic infections, 1 case of viral encephalitis, 1 case of epidermoid cyst. Glioma showed significant higher LNRmax than NNLs (3.5 ± 1.4 vs 1.7 ± 0.5, p < 0.05). The optimal thresholds of LNRmax for differentiating glioma from NNLs was 2.5. Sensitivity and specificity in the discrimination were 74.3%, 92.3% for LNRmax of 11C-MET PET and 57.1%, 46.2% for Cho/NAA of MRS. While sensitivity and specificity were 88.6%, 100% for combined evaluation of 11C-MET PET and MRS. There were no significant differences between LGGs and HGGs for LNRmaxand Cho/NAA (p = 0.159 and p = 0.099, respectively).
Conclusions: 1H-MRS can provide a complementary information for glioma diagnostic of 11C-MET PET.