Uptake in sympathetic ganglia on 68 Ga-PSMA-HBED PET/CT: A potential pitfall in scan interpretation.

INTRODUCTION: The aim of this study was to assess the frequency of PSMA-HBED uptake in coeliac and stellate ganglia in patients presenting for PSMA-HBED PET/CT scan.

METHODS: Prostate-specific membrane antigen-HBED PET/CT scans of 100 consecutive patients were analysed. Coeliac and stellate ganglia were identified by their anatomical location. PSMA-HBED uptake in these ganglia was recorded as either present or absent. If present, the SUVmax value for each ganglion was measured and compared to SUVmax of mediastinal blood pool.

RESULTS: Of the 100 patients, 45 had PSMA-HBED uptake in the right coeliac ganglion and 81 had PSMA-HBED uptake in the left coeliac ganglion. The mean SUVmax for the right coeliac ganglion was 2.6 (range 1.2-4.0) and for the left, 2.7 (range 1.2-6.5). An SUVmax 1.5 times greater than that of mediastinal blood pool activity was found in 25 of right and 47 of left coeliac ganglia. Stellate ganglion uptake of PSMA-HBED was identified in 54 of right and 74 of left stellate ganglia. The mean SUVmax for the right and left stellate ganglia were 2.2 (range 1.6-3.6) and 2.4 (range 1.4-4.2) respectively. An SUVmax 1.5 times greater than that of mediastinal blood pool activity was found in 12 of right and 32 of left coeliac ganglia.

CONCLUSION: Uptake in coeliac and stellate ganglia is a frequent finding on PSMA-HBED PET/CT imaging. Often this uptake can be sufficiently high to cause potential diagnostic confusion. It is important to be aware of this physiologic uptake to avoid incorrect diagnosis of metastatic prostate carcinoma.