title: Adding 11C-acetate to 18F-FDG at PET Examination Has an Incremental Value in the Diagnosis of Hepatocellular Carcinoma.
abstract: 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 (11)C-acetate has shown a higher accuracy than with FDG. In the current study, the uptake of (11)C-acetate has been compared with the uptake of FDG in the primary HCC in a cohort of Occidental patients.
  
  
  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 (11)C-acetate (p<0.001). Median tumor SUVmean of (11)C-acetate was 4.7 and of FDG was 1.9 (p<0.001). There was also a higher uptake of (11)C-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 (11)C-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.
  
  
  CONCLUSIONS
  Adding registration with (11)C-acetate to registration with FDG at PET-examination has an incremental value in the diagnosis of HCC. A higher tumor uptake of (11)C-acetate cannot be taken full advantage of because of a higher uptake also by the surrounding liver tissue.
  
  
  BACKGROUND
  None declared.
authors.affiliation: Karolinska University Hospital Solna, Departments of Radiology and Nuclear Medicine, Solna, Sweden.
authors.forename: Patricia
authors.initials: P
authors.lastname: Larsson
authors.forename: Dag
authors.initials: D
authors.lastname: Arvidsson
authors.forename: Mikael
authors.initials: M
authors.lastname: Björnstedt
authors.forename: Bengt
authors.initials: B
authors.lastname: Isaksson
authors.forename: Ulf
authors.initials: U
authors.lastname: Jersenius
authors.forename: Hooman
authors.initials: H
authors.lastname: Motarjemi
authors.forename: Hans
authors.initials: H
authors.lastname: Jacobsson
keywords: (11C)-acetate; 18F-FDG; Hepatocellular carcinoma; positron-emission; sensitivity; tomography