DRD2 expression based on 18F-fallypride PET/MR predicts the dopamine agonist resistance of prolactinomas: a pilot study

Abstract

The dopamine agonists (DA) have been used widely to treat prolactinomas. However, it is di cult to predict whether the patient will be responsive to DA treatment. MethodsWe aimed to investigate whether the in vivo expression of DRD2 based on 18 F-fallypride PET/MR could predict the therapeutic effect of DA on prolactinomas.Seven patients with prolactinomas who underwent surgery and further tumor immunohistochemistry completed 18 F-fallypride PET/MR preoperatively. Imaging ndings and immunohistochemical staining were compared with treatment outcomes. Results18 F-fallypride PET/MR was visually positive in 7 of 7 patients, and DRD2 target speci city could be con rmed by immunohistochemical staining. A signi cantly lower tracer standard uptake value (SUV) could be detected in the resistant patients (n = 3) than in the sensitive patients (n = 4; SUV mean , 4.67 ± 1.32 vs. 13.57 ± 2.42, p < 0.05). DRD2 expression determined by 18 F-fallypride PET/MR corresponded with the DA treatment response. Conclusion18 F-fallypride PET/MR represents an effective diagnostic tool to predict DA response in patients with prolactinoma.