Enabling minimal invasive parathyroidectomy for patients with primary hyperparathyroidism using Tc-99m-sestamibi SPECT-CT, ultrasound and first results of (18)F-fluorocholine PET-CT

Objective: Assessment of the diagnostic value of ultrasound (US), single photon-emission computed tomography-computed tomography (SPECT-CT) and (18)F-fluorocholine (FCH) PET-CT for preoperative localization of hyper-functioning parathyroid(s) in order to create a more efficient diagnostic pathway and enable minimal invasive parathyroidectomy (MIP) in patients with biochemical proven non-familial primary hyperparathyroidism (pHPT).

Methods: A single-institution retrospective study of 63 consecutive patients with a biochemical diagnosis of non-familial pHPT who received a Tc-99m-sestamibi SPECT-CT and neck ultrasound. Surgical findings were used in calculating the sensitivity and the positive predictive value (PPV) of both imaging modalities. Furthermore we present 5 cases who received additional FCH PET-CT.

Results: A total of 42 (66.7%) patients underwent MIP. The PPV and sensitivity of SPECT-CT, 93.0% and 80.3%, were significantly higher than those of US with 78.3% and 63.2%, respectively. Adding US to SPECT-CT for initial pre-operative localization did not significantly increase sensitivity but did significantly decrease PPV. Performance of US was significantly better when performed after SPECT-CT. (18)F-fluorocholine PET-CT localized the hyper-functioning parathyroid gland in 4/5 cases with discordant conventional imaging, enabling MIP.

Conclusion: SPECT-CT is the imaging modality of choice for initial pre-operative localization of hyper-functioning parathyroid gland(s) in patients with biochemical pHPT. Ultrasound should be performed after SPECT-CT for confirmation of positive SPECT-CT findings and for pre-operative marking allowing MIP. In cases with negative or discordant imaging additional FCH PET-CT should be considered since this might enable the surgeon to perform MIP.