Table 3.

Summary of evidence-based suggestions for further evaluation of incidental FDG uptake in the abdomen and pelvis and bone^a

Site of focal uptake	Evidence/when to further evaluate	Recommended form of evaluation
Stomach	Insufficient evidence
Colon	Refer focal colonic uptake with SUVmax > 5.9 Urgent referral if SUVmax > 11.446 No good evidence on the significance of focal colonic uptake with SUVmax < 5.9	Colonoscopy or virtual colonoscopy
Pancreas	Investigate foci which are not most likely part of a more widespread disease process, e.g. lymphoma or metastatic cancer	MRI or CT
Liver, gallbladder, spleen and kidney	Inadequate evidence, benign and malignant causes can be avid. Take into account patient characteristics, CT appearances and publications on CT features.62–64	Ultrasound, CT or MRI
Adrenal: patients without known cancer or hormonal hypersecretionb	Evaluate nodules with a nodule:liver SUV max ratio > 1.8.67 Consider following up other patients, e.g. if the SUVmax ratio is close to 1.8 or the CT features are non diagnostic.	Adrenal CT or MRI
Adrenal: patients with cancerb	The combination of FDG uptake ≤ liver or CT criteria: HU < 10 or macroscopic fat is highly accurate in distinguishing benign nodules from metastases68 An SUVmax ratio (adrenal:liver) of > 2.5 had been shown to exclude all benign nodules.70 Nodules not characterized by the above criteria require further evaluation	Adrenal CT or MRI
Prostate	Test all males aged > 50 Test males aged 40–50 years if the focus is peripheral, they are of black ethnicity or have affected first degree relatives.	PSA testing
Ovaries	Post-menopausal females: refer increased ovarian/adnexal uptake. Pre-menopausal females: refer ovarian uptake which is not occurring around midcycleor uptake at these times which is associated with concerning CT features.	Pelvic ultrasound
Uterus	Post-menopausal: refer endometrial uptake unless it has typical appearances of fibroids with low grade uptake. Pre-menopausal: Uptake occurring outside of midcycle or menstruation or fibroid related FDG uptake significantly above liver79, 82 should be considered for further evaluation	Pelvic ultrasound
Testis	Insufficient evidence
Bone	Foci without CT abnormalities: insufficient evidence for patients without cancer. Consider focus as suspicious for a metastasis in patients with cancer	Consider MRI

^aLimitations in SUV reproducibility and individual patient characteristics, particularly other life-limiting comorbidities and patient choice, should be taken into account when using this evidence.

^bUsing PET-CT to characterize nodules < 1 cm should be done with caution.

FDG, fluorodeoxyglucose; PSA, prostate specific antigen; SUV, standardized uptake value.