Focal colorectal uptake in (18)FDG-PET/CT: maximum standard uptake value as a trigger in a semi-automated screening setting

BACKGROUND: Focal colorectal uptake in (18)FDG-PET/CT may be associated with a malignancy and can be quantified. This provides the basis for an automatic trigger threshold above which cases are flagged for colonoscopic evaluation and below which for individual assessment. PURPOSE: To determine the lowest maximum standard uptake (SUV(max)) in colorectal cancer that could be used as a threshold to trigger endoscopic evaluation and to evaluate whether the SUV(max) needs to be further normalised to a priori known extrinsic factors. METHODS: The SUV(max) was measured in 54 colorectal carcinomas and correlated with gender, age, blood glucose level, injected activity, body mass index and time to scan using t test or correlation coefficients (Pearson or Spearman, according to distribution). RESULTS: There was no correlation between SUV(max) and any of the extrinsic factors mentioned above. The lowest SUV(max) value was 5 [mean ± SD (range): 11.1 ± 4.8 (5.0–24.6)]. CONCLUSION: In contrast to most other screening techniques, semi-automation in colorectal screening seems possible with PET/CT. This opens the door for further study into the feasibility of automated screening. Independent from extrinsic factors, an SUV(max) ≥5.0 in a focal colorectal uptake in (18)FDG-PET/CT should automatically trigger for endoscopic evaluation, if not contraindicated. Cases with SUV(max) <5 should be assessed individually before referral for endoscopy. Thus, more interpretation time could be spent on those cases with a lower uptake and more ambiguous diagnosis. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40001-016-0195-z) contains supplementary material, which is available to authorized users.