Can positron emission tomography with the dual tracers [11 C]acetate and [18 F]fludeoxyglucose predict microvascular invasion in hepatocellular carcinoma?

Microvascular invasion is a poor prognostic indicator of the recurrence of hepatocellular carcinoma (HCC) after surgical treatment. Positron emission tomography (PET) with [(18) F]fludeoxyglucose ([(18) F]FDG) as a tracer has been employed to predict the prognosis before surgery for various kinds of tumors, but it has not been found to be sensitive enough for HCC. Thus, [(11) C]acetate has been adopted as an additional tracer. This study was designed to evaluate the ability of dual-tracer PET ([(18) F]FDG and [(11) C]acetate) to predict microvascular invasion before liver resection or transplantation. Fifty-eight HCC patients who were preoperatively examined with whole-body dual-tracer PET were studied. Twenty-five patients were [(18) F]FDG-positive, and 56 were [(11) C]acetate-positive. The sensitivity of [(18) F]FDG in detecting primary HCC was 43%, and the sensitivity of [(11) C]acetate was 93%. Twenty-nine patients had HCC with microvascular invasion according to the final pathological examination. The sensitivity, specificity, positive predictive value, and negative predictive value of [(18) F]FDG PET in predicting microvascular invasion were 55.2%, 69%, 64%, and 60.6%, respectively; the corresponding rates for [(11) C]acetate PET were 93.1%, 0%, 48.2%, and 0%. The factors associated with HCC recurrence, which included multifocal involvement, a large tumor size, microsatellite lesions, poor HCC differentiation, and an advanced stage of disease, were analyzed and compared with positive PET results. A tumor size greater than 5 cm was significantly associated with positive [(18) F]FDG PET results; [(11) C]acetate was not associated with poor prognostic indicators. Preoperative [(18) F]FDG PET may predict microvascular invasion. The addition of [(11) C]acetate improves the overall sensitivity of PET, but it has no incremental value in predicting microvascular invasion.