In vitro proton magnetic resonance spectroscopic lactate and choline measurements, 18F-FDG uptake, and prognosis in patients with lung adenocarcinoma

Abstract

It has been reported that (18)F-FDG uptake, lactate concentration, and choline concentration are good indicators of malignant grade in several different kinds of tumors. In this study, we investigated the correlation between (18)F-FDG uptake in (18)F-FDG PET imaging, lactate concentration and choline concentration measured by in vitro (1)H magnetic resonance spectroscopy (MRS), and survival probabilities in human lung adenocarcinoma.

Methods: Nineteen patients with lung adenocarcinoma underwent (18)F-FDG PET before surgery. The (1)H MRS spectra were obtained in vitro from methanol-chloroform-water extracts of lung adenocarcinomas and normal lungs. The ratios of the lactate (R(lac)) or choline (R(cho)) concentration of lung adenocarcinoma to normal lung from the same patient were correlated with the mean standardized uptake value (SUV). The Kaplan-Meier life table method was used to analyze the relationship between (18)F-FDG uptake, R(lac), R(cho), and patient survival probabilities.

Results: There was no significant correlation between mean SUV and R(lac) or R(cho) in patients with lung adenocarcinoma. An SUV > 5 means poorer survival probabilities in patients with lung adenocarcinoma (P = 0.004). A higher R(lac) probably indicates a trend for patients with lung adenocarcinoma to have poorer survival probabilities; however, R(cho) is not an indicator of survival probability. (18)F-FDG uptake significantly correlated with cell differentiation (P = 0.007), whereas R(lac) and R(cho) had no correlation with it.

Conclusion: No significant correlation was found between SUV and R(lac) or R(cho) in patients with lung adenocarcinoma. Compared with R(lac) and R(cho) measured by in vitro MRS, (18)F-FDG uptake is a better indicator of prognosis in patients with lung adenocarcinoma.