Variations in F-18-FDG uptake in breast cancer depending on PET/CT acquisition position

초록

AIM: To evaluate the variability of quantitative 2-[F-18]-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography (PET) combined with computed tomography (CT) parameters depending on acquisition position in a dual-position protocol for breast cancers. MATERIALS AND METHODS: For initial staging work-up, whole-body PET/CT was first acquired in a supine position, and then followed by a regional breast scan in a prone position. The maximum standardised uptake value (SUVmax), metabolic tumour volume (MTV), and total lesion glycolysis (TLG) were measured on both acquisition positions. MTV50 and TLG(50) were calculated with a threshold set to be 50% of SUVmax, and MTV2.5 and TLG(2.5) with a fixed SUV threshold of 2.5. RESULTS: The median SUVmax of breast cancers measured on the supine scans was 4.88, and 4.49 on the prone images (p<0.05). MTV and TLG also yielded significantly lower values from supine images. Regarding the tendency for the acquisition position to yield different results, a significant disagreement was observed between SUVmax and MTV50 and between SUVmax and TLG(50) (kappa = -0156 and -0.001, respectively), while MTV2.5 and TLG(2.5) showed a fair to moderate agreement with SUVmax (kappa = 0.311 and 0.416, respectively). CONCLUSIONS: SUVmax, MTV, and TLG yielded lower values when acquired in the prone position compared to in the supine position. This observation could be due to the partial volume effect. When using 50% of SUVmax as a threshold, there was a significant discordance between SUVmax and volumetric parameters. Thus, acquisition position may affect quantitative PET/CT parameters and the clinical implications. (C) 2015 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

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