The combination of N-13-ammonia and C-11-methionine in differentiation of residual/recurrent pituitary adenoma from the pituitary gland remnant after trans-sphenoidal Adenomectomy

BackgroundThis study aimed to assess the clinical usefulness of N-13-ammonia and C-11- Methionine (MET) positron emission tomography (PET)/ computed tomography (CT) in the differentiation of residual/recurrent pituitary adenoma (RPA) from the pituitary gland remnant (PGR) after trans-sphenoidal adenomectomy.MethodsBetween June 2012 and December 2019, a total of 19 patients with a history of trans-sphenoidal adenomectomy before PET/CT scans and histological confirmation of RPA after additional surgery in our hospital were enrolled in this study. Images were interpreted by visual evaluation and semi-quantitative analysis. In semi-quantitative analysis, the maximum standard uptake value (SUVmax) of the target and gray matter was measured and the target uptake/gray matter uptake (T/G) ratio was calculated.ResultsThe T/G ratios of N-13-ammonia were significantly higher in PGR than RPA (1.580.69 vs 0.63 +/- 1.37, P