Dilemma on Pancreatic Uncinate Process Uptake on Ga68-DOTA Peptide PET/CT in Pediatric Neuroblastoma: Physiologic or Metastases?

Objective: The Ga68-DOTATATE PET/CT scan is an alternative imaging modality for the follow-up of children with neuroblastoma when the I123-MIBG scan was negative or weak. Somatostatin receptors (SSR) can be expressed in neuroblastoma lesions, and when this happens, targeting these receptors may be a good alternative to treating this disease in addition to conventional treatments. Our aim is to focus on the interpretation of one of the physiological tracer uptake sites, the uncinate process of the pancreas, using DW-MRI scans.

Methods: We present and discuss 4 cases with neuroblastoma for a technical note. Imaging scans for SSR were performed using Ga68-DOTATATE PET/CT, and all showed varying degrees of increased uptake at the uncinate process of the pancreas on PET/CT images. We also performed a DW-MRI study to distinguish physiologic uptake in this region of the pancreas from metastatic involvement.

Results: Two of them showed diffusion restriction, with one of them also showing multiple masses within the liver. The other 2 children with high pancreatic uncinate process uptake did not exhibit any findings that indicated pancreatic involvement in the disease, based on DW-MRI images and clinical findings.

Conclusion: We recommend comparing DW-MRI scans and SSR-PET/CT scans to determine the true state of physiologically elevated SSR concentration and consequently indicate increased uptake on the images. The radiotracer concentration at the high uptake site did not appear to correlate with malignant involvement of the organ. The higher number of patients may allow a statistical comparison of the tracer with malignancy status.