123I-Metaiodobenzylguanidine Imaging in the Era of Implantable Cardioverter Defibrillators: Beyond Ejection Fraction

Abstract

1171 Objectives To evaluate the effect of patient respiration on lesion detection and SUV in patients with lung or abdominal malignancy using 4D RG PET/CT. Methods 74 pts with 120 CT detected neoplastic lesions (82 lung, 32 liver, 4 LNs, 2 adrenal glands, mean diam.= 13.1 mm, range 4-70 mm) candidate for clinical evaluation to FDG-PET/CT were studied in three italian PET centres using the same protocol. A standard whole-body PET/CT was performed including a 4D RG PET/CT list mode 10 min acquisition, synchronised to the respiratory cycle, on 2 bed positions centred on the regions presenting with the lesions. 4D RG PET/CT data were unlisted, sorted and reconstructed as follows: a) 4D RG PET/CT phases (BIN1 to BIN4, 2.5 min each, 4D CT attenuation correction), b) “High Statistics” PET image (HS, 10 min, average 4D CT attenuation correction), c) whole body image (WB, 2.5 min, whole-body CT attenuation correction). Images were analysed by visual inspection (contrast score:1 to 3) and by SUVmax (SUV). %SUV differences were calculated between HS, 4D RG BIN [mean and max among the 4 BINs], with respect to WB. Results 81 of the 120 lesions were all detected on HS, RG BIN 1-4 and WB images, whereas the remaining lesions did not show FDG uptake. Visual score increased by 4.2%, 4.7% and 7.5% for HS, mean 4D RG BIN and max RG BIN, with respect to WB. A mean %SUV increase of 7.2%, 20.3% and 38.7% for HS, mean 4D RG BIN and max 4D RG BIN, respectively was found. Conclusions 4D RG PET/CT provides more accurate visual and semi-quantitative characterization of lesions located in the thorax and abdominal regions. Marked SUV underestimation has to be expected when PET emission data are not corrected for motion artefacts. Although lesion detectability does not change, confidence of physicians in lesion characterization improves