Dynamic image analysis of [18F]-DOPA PET in patients with hyperinsulinism

Abstract

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Objectives: Seventy-eight patients diagnosed with hyperinsulinism were imaged with [18F]fluoro-DOPA ([18F]-DOPA) PET using a dynamic image acquisition protocol. The objective of the current study was to determine whether dynamic acquisition conferred any incremental advantage in identifying focal disease.

Methods: Each patient was injected with 2.96 – 5.92 MBq/kg of [18F]-DOPA and underwent dynamic PET consisting of five 10-minute acquisitions, starting ~10 minutes after injection. Scans were acquired on a GSO-based PET scanner with 256 mm transverse and axial fields of view. 3D regional analysis was performed, using the Philips Syntegra software package, on the image set to obtain a graph of pancreatic uptake over time. Regions were drawn around the head, body and tail of the pancreas using a summed PET image, and applied to each of the individual time frames. The average and maximum counts for each region were recorded and plotted. The plots were then analyzed for systematic differences between diffuse and focal disease uptake patterns.

Results: Currently 15 cases have been analyzed using the regional analysis methods (5 pathologically confirmed focal, 5 pathologically confirmed diffuse and 5 read as diffuse from PET, but confirmed focal by pathology). Uptake in the regions varied over time; there were no apparent systematic differences between uptake patterns in focal lesions and elsewhere in the dynamic data sets.

Conclusions: Parametric analysis of dynamic [18F]-DOPA PET images may not provide incremental diagnostic utility in differentiating focal from diffuse HI in the studied population. A single acquisition approximately an hour after injection, comparable to that used for FDG PET imaging, may suffice. Further analysis continues.