Added diagnostic value of respiratory-gated 4D 18F–FDG PET/CT in the detection of liver lesions: a multicenter study
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The aim of the present study was to evaluate the added diagnostic value of respiratory-gated 4D18F–FDG PET/CT in liver lesion detection and characterization in a European multicenter retrospective study.
Fifty-six oncological patients (29 males and 27 females, mean age, 61.2 ± 11.2 years) from five European centers, submitted to standard 3D–PET/CT and liver 4D–PET/CT were retrospectively evaluated. Based on visual analysis, liver PET/CT findings were scored as positive, negative, or equivocal both in 3D and 4D PET/CT. The impact of 4D–PET/CT on the confidence in classifying liver lesions was assessed. PET/CT findings were compared to histology and clinical follow-up as standard reference and diagnostic accuracy was calculated for both techniques. At semi-quantitative analysis, SUVmax was calculated for each detected lesion in 3D and 4D–PET/CT.
Overall, 72 liver lesions were considered for the analysis. Based on visual analysis in 3D–PET/CT, 32/72 (44.4%) lesions were considered positive, 21/72 (29.2%) negative, and 19/72 (26.4%) equivocal, while in 4D–PET/CT 48/72 (66.7%) lesions were defined positive, 23/72 (31.9%) negative, and 1/72 (1.4%) equivocal. 4D–PET/CT findings increased the confidence in lesion definition in 37/72 lesions (51.4%). Considering 3D equivocal lesions as positive, sensitivity, specificity, and accuracy were 88.9, 70.0, and 83.1%, respectively, while the same figures were 67.7, 90.0, and 73.8% if 3D equivocal findings were included as negative. 4D–PET/CT sensitivity, specificity, and accuracy were 97.8, 90.0, and 95.4%, respectively, considering equivocal lesions as positive and 95.6, 90.0, and 93.8% considering equivocal lesions as negative. The SUVmax of the liver lesions in 4D–PET (mean ± SD, 6.9 ± 3.2) was significantly higher (p < 0.001) than SUVmax in 3D–PET (mean ± SD, 5.2 ± 2.3).
Respiratory-gated PET/CT technique is a valuable clinical tool in diagnosing liver lesions, reducing 3D undetermined findings, improving diagnostic accuracy, and confidence in reporting. 4D–PET/CT also improved the quantification of SUVmax of liver lesions.
KeywordsRespiratory gating Positron emission tomography Computed tomography Liver lesion detection/characterization SUV
Compliance with ethical standards
The authors disclose that they did not receive any personal or financial support for this multicenter study.
Conflict of interest
Luca Guerra has had honorarium from GE Healthcare for speaking at symposia. All other authors declare that they have no conflicts of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Informed consent was obtained from all participants included in the study.
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