Introduction: In the differentiation of malignant brain tumours the apparent diffusion coefficient
(ADC) and the relative cerebral blood volume (rCBV) obtained by MRI have been evaluated1.
Aim of this study was to investigate the relation between 11C-MET and 18F-FLT as amino
acids for the assessment of proliferation in PET to rCBV respectively to the ADC.
Marterial and methods: In total 19 patients with primary glioma were included. All patients underwent 11C-MET
PET investigation, 10 patients 11C-MET and 18F-FLT PET. DW and PW images were performed
in 17 of 19 patients. The relative cerebral blood volume (rCBV), the apparent diffusion
coefficient (ADC), 11C-MET uptake and 18F-FLT uptake were determined by using a region
of interest (ROI) approach.
Results: Maximal rCBV ratios within in the tumour are strongly related to the highest 11C-MET
and 18F-FLT uptake ratios (MET: r=0.89, p<0.001; FLT: r=0.68, p=0.05). After co-registration
in the tumour with the highest rCBV also increased 11C-MET uptake/18F-FLT ratios were
found (MET: r=0.66, p=0.004; FLT: r=0.77, p=0.016). An inverse correlation was observed
between the ADC ratio and the uptake ratios of 11C-MET and 18F-FLT (11C-MET: r=–0.76,
p=0.001; 18F-FLT: r=–0.77, p=0.73).
Conclusion: The strong relation between high metabolism of 11C-MET and 18F-FLT and rCBV ratios
respectively ADC ratios indicates that high proliferating parts of the tumour as depicted
by PET are associated to a high perfusion and a high cellular density detected by
MR.
References:
1. Calli, C., O. Kitis, et al. (2006). “Perfusion and diffusion MR imaging in enhancing
malignant cerebral tumors.“ Eur J Radiol 58(3): 394–403.
„Supported in part by EC-FP6-project DiMI, LSHB-CT-2005–512146 and EMIL, LSHB-CT-2004–503569“
