Brain tumour imaging with carbon-11 choline: comparison with FDG PET and gadolinium-enhanced MR imaging

The purpose of this study was to assess the clinical potential of methyl-¹¹C-choline (¹¹C-choline) in the diagnosis of brain tumours. To this end, the results of ¹¹C-choline positron emission tomography (PET) in 22 patients suspected of having brain tumours were compared with the findings of contrast-enhanced magnetic resonance (MR) imaging and fluorine-18 fluorodeoxyglucose PET. A histopathological diagnosis was made for each patient during open surgery. The standardised uptake values of brain tumours and the tumour-to-white matter count (T/W) ratios were determined. The degree of ¹¹C-choline accumulation noted in PET images was compared with the gadolinium-enhanced areas of MR images. The mean T/W ratio of ¹¹C-choline in high-grade gliomas was found to be higher than that in low-grade gliomas. This difference was statistically significant (mean-SD: 8.7Lj.2, n=9 versus 1.5ǂ.7, n=5, P<0.03) when data pertaining to the prominent uptake of ¹¹C-choline in a patient with a pilocytic astrocytoma were excluded. ¹¹C-choline PET failed to detect non-neoplastic lesions in two patients. Areas of ¹¹C-choline accumulation in PET scans were larger than areas enhanced on MR images in five cases involving high-grade gliomas. ¹¹C-choline PET differentiated between low-grade gliomas and high-grade gliomas, but did not differentiate between low-grade gliomas and non-neoplastic lesions. The combination of ¹¹C-choline PET and MR imaging may provide investigators with an accurate means by which to identify high-grade gliomas.