Localization of Parathyroid Adenoma by 11C-Choline PET/CT

Purpose: This prospective pilot study was aimed to evaluate C-11-choline PET/CT (choline) as a tool for localization of parathyroid adenoma (PTA). Methods: Forty patients with biochemical hyperparathyroidism underwent choline and Tc-99m-MIBI imaging within a median interval of 56 days. Choline and MIBI images were analyzed and correlated with each other, with additional modalities such as ultrasound, CT, MRI, and with surgical findings, when available. Results: Thirty-seven of forty cases were choline-positive, and 3 were cholinenegative. Choline uptake on PET was identified with corresponding nodules on CT of the PET/CT, yielding precise localization. Twenty of thirty-seven foci were located in typical sites in the neck, and 17 were ectopic. Clear visualization of PTA was achieved in 33 of 37, whereas findings in 4 cases were suspicious for PTA. MIBI was positive in 33 of 40 cases (22 clearly positive, 11 suspicious). In 29 of 40 cases, choline and MIBI were concordant, but choline findings were clearer in 9 of these 29 studies. At the time of writing, 27 patients had undergone surgery. In 24 cases, there was complete matching of choline with surgical findings of PTA. Overall in 23 cases, both choline and MIBI matched surgical findings of PTA. In 1 case, PTA was correctly localized on choline but not on MIBI, and in 2 cases, neither choline nor MIBI corresponded to the surgical findings. Conclusions: These preliminary results indicate that the combined functional and anatomical modality of choline PET/CT is a promising tool for PTA localization, providing clearer images than MIBI, equal or better accuracy, and quicker and easier acquisition.