Table 2.
Clinical applications of 11C-methionine uptake measured by PET in adult low-grade gliomas (LGGs).
| Study | Study design | Tumor subtype1 no. of patients | Results and/or conclusion |
|---|---|---|---|
| Evaluation of response to chemotherapy | |||
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| |||
| Tang et al. [54] | Retrospective review Chemosensitivity to PCV Measures: activity volume index (AVI), FLAIR-MRI | 7 OII | PCV associated with drastic decrease in AVI; less pronounced decrease in tumor volume on FLAIR-MRI |
| Wyss et al. [72] | Prospective study TMZ in progressive nonenhancing tumors Measures: FET ratio, FET volume, and MRI | 11 LGGs (3 OII, 4 AII, 4 AOII) | Changes in FET preceded and more pronounced than MRI changes; decrease FET ratio < FET volume in responders |
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| Differentiating recurrent tumor from changes induced by radiotherapy | |||
|
| |||
| Van Laere et al. [73] | Retrospective review Differential diagnosis radionecrosis-recurrence Measures: MET ratio, FDG ratio, histology, and survival | 30 gliomas (15 LGGs: 8 AAII, 3 OAII, 4 OII) | FDG and MET ratio significant parameters for survival; FDG and MET strongest prognostic accuracy; MET alone strongest prognostic factor for astrocytomas |
| Terakawa et al. [74] | Retrospective review Differential diagnosis radionecrosis-recurrence Measures: MET ratio (L/N mean, L/N max, lesion/normal frontal cortex), histology | 77 patients (26 gliomas: 6 grade II, 6 grade III and 14 GB; 51 metastases) | L/N mean with cutoff 1.58 most informative for glioma (75% sensitivity, 75% specificity); L/N max not informative for glioma |
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| Long-term followup and prognosis | |||
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| |||
| Nuutinen et al. [63] | Prospective long-term followup Measures: MET ratio, MET volume, histology, and survival | 14 gliomas (13 AII and 1 AIII) | Met ratio and volume: 80% sensitivity in detecting residual postoperative tumor; baseline MET ratio of prognostic value |
| Ribom et al. [75] | Retrospective review Pretreatment MET Measures: MET ratio, MET volume (untreated versus after surgery/radio- and/or chemotherapy), time-to-progression (TPP) | 32 LGGs (11 AII, 6 OAII, 15 OII) | Untreated patients: longest TTP when stable MET ratio and small volume increase; treated patients: initial treatment effects (reduction MET ratio, volume or in both) but no prognostic value |
| Ullrich et al. [76] | Prospective long-term followup Measures: MET ratio, histology, and molecular tumor profile | 24 gliomas (10 AII, 7 OAII, 1 OII, 3 AIII, 3 OAIII) | Mean increase of MET in patients with progression 54.4% versus 3.9% in patients with stable disease; correlation increased MET and VEGF expression |
| Ribom et al. [77] | Retrospective review Preoperative MET Measures: MET ratio, and survival | 89 LGGs (33 AII, 17 OAII, 39 OII) | Preoperative MET ratio prognostic factor for survival in AII and OII |
| De Witte et al. [78] | Retrospective review Preoperative (n = 74) and postoperative (n = 11) MET Measures: MET ratio, survival | 85 gliomas (28 LGGs: 12 AII, 4 OAII, 12 OII) | MET ratio prognostic factor for survival in grade II and grade III gliomas |
| Floeth et al. [79] | Prospective followup Histologically verified LGGs Measures: FET ratio, growth pattern on MRI (diffuse versus circumscribed), survival | 33 LGGs (27 AII, 2 OAII, 4 OII) | 3 major subtypes: (1) low FET ratio and circumscribed on MRI most favorable outcome,(2) positive FET ratio and circumscribed on MRI intermediate outcome,(3) positive FET ratio and diffuse on MRI unfavorable outcome |
1Abbreviations: LGGs: low-grade gliomas; AI: pilocytic astrocytoma; AII: astrocytoma grade II; OII: oligodendroglioma grade II; OAII: oligoastrocytoma grade II; AIII: astrocytoma grade III; OAIII: oligoastrocytoma grade III; GB: glioblastoma.