Predicting neuroendocrine neoplasm grade with dual tracer positron emission tomography/computed tomography (PET/CT) using F-fluorodeoxyglucose (F-FDG) and F-AlF-NOTA-octreotide: a lesion-based analysis.

AIM

The aim of this study was to investigate the ability of dual tracer positron emission tomography/computed tomography (PET/CT) using F-fluorodeoxyglucose (F-FDG) and F-AlF-NOTA-octreotide (F-OC) in predicting neuroendocrine neoplasm (NEN) grade. The lesions that have been histologically confirmed were accurately located using both F-FDG and F-OC PET/CT.

MATERIALS AND METHODS

For each lesion, the standardized uptake value (SUV) was measured, and tumor-to-background ratio was calculated by dividing the SUV by the SUV of background tissue at the two scans. SUVR was calculated by dividing the SUV of the lesion at F-OC PET/CT by the SUV at F-FDG PET/CT. For evaluating the correlation between continuous variables and lesion grade, the Spearman rank correlation test was used. Receiver operating characteristic (ROC) curve was used to evaluate the performance of PET/CT parameter in discriminating lesions of different grades.

RESULTS

A total of 49 patients (22 males, 27 females; mean age: 56.5 ± 14.3 years; range: 14-85 years) and 65 lesions were included in this study. A substantial correlation was observed between SUVR and lesion grade (rho = -0.655, p < 0.001), better than other PET/CT parameters. For discriminating G1/2 neuroendocrine tumor (NET) from G3 NET and neuroendocrine carcinoma (NEC), SUVR had the largest area under ROC curve (AUC) of 0.88. With the cut-off value of 2.217, we got the best Youden's index, 0.668. For discriminating G1/2/3 NET from NEC, SUVR and OC SUV had the largest AUC of 0.923. With the cut-off value of OC SUV of 4.35, we got the best Youden's index, 0.805.

CONCLUSION

This study suggests that F-FDG and F-OC PET/CT are complementary in evaluating the grade of NEN and that SUVR is a promising tool for predicting NEN grade.