Accurate pre-operative localization of pathological parathyroid glands using 11C-methionine PET/CT

The pre-operative technique most routinely used to localize pathological parathyroid glands (PPG), prior to minimal access surgery (MAS), relies on 99mTc-sestamibi (MIBI) scintigraphy. Positron emission tomography (PET) using the radiolabelled amino acid 11C-methionine as the tracer agent offers a technological alternative to localize PPG. In this study we evaluated the sensitivity of 11C-methionine PET/CT (MET-PET/CT) for PPG detection and the extent to which MET-PET/CT images may contribute to the planning of surgical procedures.

Thirty patients were included, 22 with primary hyperparathyroidism and eight with secondary hyperparathyroidism. Patients suspected of suffering from parathyroid hyperplasia underwent a complete surgical exploration of the neck region. In those suspected of parathyroid adenoma, surgery was limited to the presumed localization described by MET-PET/CT. To specifically address the additional benefit of the MET-PET/CT in terms of surgical planning and procedure, the surgeon classified the patients into two categories depending on the type of benefit, or the reason for the absence of benefit, occurring in each case. We also compared the sensitivity of MET-PET/CT and MIBI scintigraphy.

The total number of lesions removed was 46 (24 adenomatous and 22 hyperplastic). Globally, MET-PET/CT provided additional benefit to surgery in 15 out of 30 cases (50%). The sensitivity of 11C-methionine PET/CT and MIBI scintigraphy was respectively 92% and 95% for adenoma, and 68% and 59% for hyperplasia, on the basis of available resected lesions.

MET-PET/CT appears a reliable technique to guide MAS of parathyroid glands.