Adding 11C-acetate to 18F-FDG at PET Examination Has an Incremental Value in the Diagnosis of Hepatocellular Carcinoma.

Objective: The sensitivity of FDG at PET examination of Hepatocellular Carcinoma (HCC) is restricted. In a few studies, all done in Oriental patients, PET-examination with 11C-acetate has shown a higher accuracy than with FDG. In the current study, the uptake of 11C-acetate has been compared with the uptake of FDG in the primary HCC in a cohort of Occidental patients. Material and Methods: 44 patients underwent PET-examination with both tracers with a mean of 9 days between the examinations. 26 patients had a microscopical diagnosis and 18 were diagnosed with multimodal radiological methods. At least one relevant radiological examination was available for comparison. Results: At visual evaluation, 13 of the HCC’s were positive at PET-examination using FDG and 34 were positive using 11C-acetate (p<0.001). Median tumor SUVmean of 11C-acetate was 4.7 and of FDG was 1.9 (p<0.001). There was also a higher uptake of 11C-acetate by the surrounding liver tissue than of FDG. Median liver SUVmean of [u]11[/u]C-acetate was 3.2 and of FDG it was 1.7 (p<0.001). This corresponded to a median tumour/liver tissue ratio for 11C-acetate of 1.4 and for FDG of 1.0 (p<0.05). Previous reports of a negative correlation between the uptake of the tracers were weakly supported. In 4 large tumors some portions being hot using one of the tracers were cold using the other tracer and vice versa. Conclusion: Adding registration with 11C-acetate to registration with FDG at PET-examination has an incremental value in the diagnosis of HCC. A higher tumor uptake of 11C-acetate cannot be taken full advantage of because of a higher uptake also by the surrounding liver tissue. Conflict of interest:None declared.