L. Bakker*a (Dr), M. Verstegena (Mr), E. Ghariqa (Mr), B. Verbista (Dr), P. Schuttea (Mr), W. Basharib (Mr), M. Kruita (Dr), A. Pereria Ariasa (Prof), M. Gurnellb (Prof), N. Biermasza (Prof), W. Van Furtha (Dr), L. Pereira Arias - Boudaa (Dr)

a Leiden University Medical Center, Leiden, NETHERLANDS ; b Wellcome–MRC Institute of Metabolic Science, University of Cambridge and National Institute for Health Research Cambridge Biomedical Research Centre, Addenbrooke's Hospital, Cambridge Biomedical Campus, Cambridge, UNITED KINGDOM

* l.e.h.bakker@lumc.nl

Purpose: To report the first experience of our multidisciplinary team with functional imaging using 11C-methionine positron emission tomography-computed tomography (11C-methionine PET-CT) co-registered with MRI (Met-PET/MRICR) in clinical decision making and surgical planning of patients with difficult to treat prolactinoma.

Methods: In eighteen patients with prolactinoma, referred to our tertiary referral centre because of intolerance or resistance for dopamine agonists (DA), Met-PET/MRICR was used to aid decision-making regarding therapy.

Results: Met-PET/MRICR was positive in 94% of the patients. MRI and Met-PET/MRICR findings were completely concordant in five patients, partially concordant in nine patients, and non-concordant in four patients. In five patients Met-PET/MRICR identified lesion(s) that were retrospectively also visible on MRI. Met-PET/MRICR was false negative in one patient, with a cystic adenoma on conventional MRI. Thirteen patients underwent transsphenoidal surgery, with nine achieving full biochemical remission, two clinical improvement and near normalized prolactin levels, and one patient clinical improvement with significant tumour reduction. Hence, nearly all patients (94%) were considered to have a positive outcome. Permanent complication rate was low. Three patients continued DA, two patients have a wait and scan policy.

Conclusion: Met-PET/MRICR can provide additional information to guide multidisciplinary preoperative and intraoperative decision making in selected cases of prolactinoma. This approach resulted in a high remission rate with a low rate of complications in our expert centre.

The author has declared the following conflict(s) of interest:

Very recently accepted for publication in Pituitary.