Dynamic study of methionine positron emission tomography in patients with glioblastoma with oligodendroglial components

Abstract

Anaplastic oligoastrocytoma (AOA) with necrosis is classified as glioblastoma (GBM) with oligodendroglioma component (GBMO), according to the 2007 World Health Organization classification. The prognosis of GBMO remains controversial because definitive diagnostic criteria regarding the percentage of the oligodendroglial components (OC) in the GBM do not exist. We previously reported dynamic methionine (MET) positron emission tomography (PET) in patients with these tumors. A significant decrease in the MET signal was seen in oligodendrocytic tumors, in contrast to a significant MET increase in GBMs. In this study, we analyzed the dynamic MET PET signal in four patients with primary (n = 2) and secondary (n = 2) GBMOs. Static PET scanning was performed in three consecutive phases. Both cases of primary GBMOs and one case of secondary GBMO presented with a gradual decrease in MET PET signal over the consecutive phases. In contrast, the remaining case of secondary GBMO presented with a pattern of slight increase. It is likely that the dynamic change of MET in patients with GBMO resemble those in patients with oligodendroglial tumor, however, further studies are needed to confirm them. We discuss the mechanisms from a viewpoint of pathological findings.

Dynamic 11C-Methionine PET-CT: Prognostic Factors for Disease Progression and Survival in Patients with Suspected Glioma Recurrence

“…Moreover, the dynamic acquisition of 11 C-MET is not so demanding for patients, nor as time-consuming, lasting about 20 min (vs. 60 min for 18 F-FET). Unlike fluorinated aminoacid radiotracers, kinetic 11 C-MET parameters in glioma grading/diagnosis have been evaluated by few authors, finding controversial results [30,32,33]. As already pointed out, no data are available on the prognostic role of dynamic 11 C-MET PET parameters in glioma recurrent patients.…”

“…Recently, Zagori et al [29] explored the usefulness of dynamic 18 F-DOPA parameters in the prognostication of patients with suspected glioma recurrence, failing to prove the definitive primacy of these indices compared to static ones. Dynamic 11 C-MET parameters have been studied in the differential diagnosis of brain tumours [30,31] to characterise glioblastoma with an oligodendroglial component [32] and to distinguish highgrade from low-grade glioma (LGG) [33], reaching conflicting results. Since differences in uptake mechanism are present among amino-acids radiotracers, the findings observed for dynamic 18 F-FET and 18 F-DOPA in the prognostic evaluation cannot directly be translated to 11 C-MET.…”

Preoperative Texture Analysis Using 11C-Methionine Positron Emission Tomography Predicts Survival after Surgery for Glioma

“…Second, while we only included patients who underwent the same PET/CT protocol at our hospital, the textural features of PET depend on the image acquisition conditions, with different acquisition modes and reconstruction parameters potentially influencing the results [23]. Third, oligodendroglial cell differentiation may influence MET uptake [4,24], although we were unable to evaluate this factor because of the limited number of patients. Further clinical studies are needed to address these issues and to confirm whether TA provides prognostic value in the clinical management of gliomas.…”

Clinical Utility of Positron Emission Tomography in Patients with Malignant Glioma

“…A significant dynamic increase of MET T/N ratios was also observed in GBM and central nervous system lymphoma, 29) which are often indistinguishable on MRI to the extent that additional clinical data and other diagnostic modalities are required. Next, we performed dynamic MET-PET studies on GBM patients with oligodendroglial components (GBMO), 30) whose prognoses remain controversial to date. This GBMO study showed that the dynamic MET signal tended to decrease over time; these changes resembled those in the above-mentioned oligodendroglial tumors.…”

“…Accordingly, GBMO may be a possible differential diagnosis when dynamic MET-PET shows a decreasing pattern. 30) …”