This study aimed to evaluate the effect of intravenous (IV) contrast media on semi quantification value during fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT in cancer imaging. We reviewed whole body 18F-FDG PET/CT scans of 51 oncology cases performed with and without IV contrast administration. Non contrast-enhanced CT (NECT) images were acquired following IV injection of FDG then followed by contrast-enhanced CT (CECT) images acquisition utilizing non-ionizing iodinated contrast media without positional change. The contrast injection was acquired using an automatic intravascular injection conversion kit (U.S. Patent No. 5,792,102, 1998). PET images were reconstructed using both NECT and CECT image datasets. Region of interest (ROI) was drawn on field of view over the heart, liver, spleen, inferior vena cava, psoas major muscle, urinary bladder and site of lesion on PET/CECT images. Similar ROI was copied to the corresponding PET/NECT images. The maximum standardized uptake values (SUVmax) of both datasets were compared using paired sample t-test with p < 0.05 considered as significant. The mean ± standard deviation percentage differences of SUVmax between PET/CECT and PET/NECT for all investigated organs and lesions were not statistically significant (p > 0.05). Contrast-enhanced 18F-FDG PET/CT protocol did not cause significant effect in PET semiquantification uptake value, hence this protocol can be recommended in routine PET/CT examination, optimizing its role as a ‘one-stop’ imaging modality.
Keywords: Contrast-enhanced CT, FDG PET/CT, intravenous, OsiriX, semi quantification value, third party viewing workstation.