Diagnostic value of 11C-methionine PET/CT imaging for detecting the recurrence of supratentorial glioma / 中华核医学与分子影像杂志

ABSTRACT

Objective@#To assess the diagnostic values of 11C-methionine (MET) PET/CT semiquantitative parameters for detecting recurrence in patients who were diagnosed with suspicious recurrence by MRI after resection of supratentorial gliomas.@*Methods@#A total of 164 patients (107 males, 57 females, age 6-74 years; high-grade 94, low-grade 63, unclear 7) with supratentorial gliomas who underwent 11C-MET PET/CT between June 2015 and June 2017 in Beijing Tiantan Hospital were enrolled respectively. All patients were with suspicious recurrence after surgery showed by MRI and followed up for 6 months at least. The final diagnosis was determined with histopathological analysis or clinical follow-up. The maximum and mean standardized uptake value (SUVmax and SUVmean), tumor-to-background ratios (TBR) of SUVmax and SUVmean (TBRmax and TBRmean) were recorded and compared between patients with recurrence or without recurrence using independent-sample t test. Receiver operating characteristic (ROC) curves were drawn to determine the threshold, and the diagnostic sensitivity and specificity of each parameter were calculated.@*Results@#According to the clinical diagnosis, there were 139 patients with recurrence and 25 without recurrence. SUVmax, SUVmean, TBRmax and TBRmean were significantly higher for patients with recurrence than those without recurrence (4.19±1.95 vs 2.59±1.18, 2.34±1.08 vs 1.46±0.72, 2.95±1.17 vs 1.83±0.79, 2.64±1.11 vs 1.59±0.71; t values 5.126-6.183, all P<0.01), but there was no difference in the areas under the ROC curve (AUC) for diagnosis of recurrence with the 4 parameters (z values 0.265-1.674, all P>0.05), for which the optimal cut-off values were 3.05, 1.65, 1.96 and 1.79, respectively, and the corresponding sensitivities/specificities for the diagnosis of recurrence were 67.6%(94/139)/100%(25/25), 67.6%(94/139)/100%(25/25), 79.9%(111/139)/100%(25/25), 74.8%(104/139)/100%(25/25), respectively. Patients with (n=81) or without (n=13) recurrence had different semiquantitative parameters in high-grade glioma group (t values 5.137-5.871, all P<0.01), and the AUC for TBRmean was greater than that for SUVmean (0.858 vs 0.802; z=1.982, P<0.05). Patients with (n=54) or without (n=9) recurrence in low-grade glioma group showed significant difference in the 4 parameters (t values 2.730-7.009, all P<0.01), while the AUCs of the 4 parameters were not significantly different (z values 0.444-1.407, all P>0.05). Among 37 patients with recurrence confirmed by pathology, there were no significant differences in the semiquantitative parameters between the high-grade and low-grade glioma groups and AUCs were not different either (t values 1.387-1.937, z values 0.106-1.752, all P>0.05).@*Conclusions@#Semiquantitative parameters of 11C-MET PET/CT are equally accurate in the differentiation of recurrence from radiation injury in patients with gliomas, while TBRmean was superior than SUVmean in patients with the high-grade gliomas. Among the patients with recurrence confirmed by pathology, the value of the semiquantitative parameter is limited for the identification of high- and low- grade gliomas.